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AS/400e

IBM

TCP/IP Configuration and Reference
Version 4

SC41-5420-03

AS/400e

IBM

TCP/IP Configuration and Reference
Version 4

SC41-5420-03

Note
Before using this information and the product it supports, be sure to read the information in “Notices” on page 595.

Fourth Edition (May 1999)
This edition replaces SC41-5420-02. This edition applies only to reduced instruction set computer (RISC) systems.
© Copyright International Business Machines Corporation 1997, 1999. All rights reserved.
Note to U.S. Government Users — Documentation related to restricted rights — Use, duplication or disclosure is
subject to restrictions set forth in GSA ADP Schedule Contract with IBM Corp.

Contents
About TCP/IP Configuration and Reference
TCP/IP Topics in the Information Center . .
Who should read this book . . . . . . .
AS/400 Operations Navigator . . . . . .
Installing Operations Navigator. . . . .
Prerequisite and related information . . . .
How to send your comments . . . . . .

(SC41-5420)
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Chapter 1. TCP/IP on AS/400 . . . . . . .
Linking Networks Together . . . . . . . .
Internetwork Communications . . . . . . .
Internet Addresses . . . . . . . . . . .
Accessing the Internet . . . . . . . . .
IP Security . . . . . . . . . . . . .
Classes of Networks . . . . . . . . .
IP Subnets . . . . . . . . . . . . . .
Subnetworks and Subnet Masks . . . . . .
Broadcast Addresses . . . . . . . . . .
Domain Name System (DNS) . . . . . . .
Domain and Host Name . . . . . . . .
Naming Conventions for Domain Names and
Routing . . . . . . . . . . . . . . .
Introduction to TCP/IP Protocols on AS/400 . .
Application Protocols . . . . . . . . . .
Application Protocol Standards. . . . . .
OS/400 Network File System Support . . .
Application Program Interfaces (APIs) . . .
Transport Protocol . . . . . . . . . . .
Transmission Control Protocol (TCP) . . . .
User Datagram Protocol (UDP) . . . . . .
TCP and UDP Ports . . . . . . . . .
Point-to-Point TCP/IP . . . . . . . . .
Internetwork Protocol . . . . . . . . . .
Internet Protocol . . . . . . . . . . .
Internet Control Message Protocol . . . .
Internet Group Management Protocol . . .
Address Resolution Protocol . . . . . .
AnyNet/400 . . . . . . . . . . . . .

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Chapter 2. Configuring TCP/IP . . . . . . . . . .
What you need to know before you can configure TCP/IP .
Planning for TCP/IP Installation and Configuration . . .
Gathering Information About your Network . . . . .
Installing the TCP/IP Application Programs . . . . . .
TCP/IP Addressing . . . . . . . . . . . . . . .
Using the TCP/IP Administration Menu . . . . . . . .
Using the Configure TCP/IP Menu . . . . . . . . .
Configuring TCP/IP using the Command Line Interface . .
Step 1—Configuring a Line Description . . . . . .
Step 2—Configuring a TCP/IP Interface . . . . . .
Step 3—Configuring TCP/IP Routes . . . . . . . .
Step 4—Configuring TCP/IP attributes . . . . . . .
Step 5—Configuring TCP/IP Remote System Information
© Copyright IBM Corp. 1997, 1999

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Step 6—Configuring TCP/IP Host Table Entries
Step 7—Configuring the Local Domain and Host
Step 8—Starting TCP/IP and TCP/IP Servers .
Step 9—Verifying the TCP/IP Connection . . .
Verifying Additional TCP/IP Connections . . .
Step 10—Saving Your TCP/IP Configuration . .
TCP/IP Planning Checklists . . . . . . . .
Sample Network Drawing. . . . . . . . .

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Chapter 3. TCP/IP: Operation, Management, and Advanced Topics
Network Status . . . . . . . . . . . . . . . . . . . .
Work with TCP/IP Network Status Menu . . . . . . . . . .
Work with TCP/IP Interface Status . . . . . . . . . . . .
Display TCP/IP Route Information . . . . . . . . . . . .
Work with TCP/IP Connection Status . . . . . . . . . . .
Working with Configuration Status . . . . . . . . . . . .
Displaying TCP/IP Network Status Information . . . . . . . .
TCP/IP Host Tables . . . . . . . . . . . . . . . . . . .
Managing TCP/IP Host Tables . . . . . . . . . . . . . . .
Host File Formats . . . . . . . . . . . . . . . . . .
Tips for Merging Host Tables . . . . . . . . . . . . . .
Merging TCP/IP Host Tables . . . . . . . . . . . . . .
Managing the Host Table from a Central Site . . . . . . . .
Domain Name System (DNS) Server . . . . . . . . . . . .
IP Routing and Internet Control Message Protocol (ICMP) Redirecting
Dead Gateway Processing . . . . . . . . . . . . . . . .
Negative Advice from TCP or the Data Link Layer . . . . . .
How IP Responds to Negative Advice . . . . . . . . . . .
Multihoming Function . . . . . . . . . . . . . . . . . .
Example: A Single Host on a Network over a Communications Line
Example: Multiple Hosts on the Same Network over the Same
Communications Line . . . . . . . . . . . . . . . .
Example: Multiple Hosts on the Same Network over Multiple
Communications Lines . . . . . . . . . . . . . . . .
Example: Multiple Hosts on Different Networks over the Same
Communications Line . . . . . . . . . . . . . . . .
Example: Multiple Hosts on Different Networks over Multiple
Communications Lines . . . . . . . . . . . . . . . .
Example: The Multihoming function . . . . . . . . . . . . .
Type of Service (TOS) . . . . . . . . . . . . . . . . .
Multiple Routes . . . . . . . . . . . . . . . . . . .
TCP/IP Port Restriction . . . . . . . . . . . . . . . . .
Configuring TCP/IP Port Restrictions . . . . . . . . . . .
Related Tables and the Host Table . . . . . . . . . . . . .
Using X.25 PVC instead of SVC . . . . . . . . . . . . . .
IP Multicasting. . . . . . . . . . . . . . . . . . . . .
Multicast Application Programming Information . . . . . . . .
Multicast Restrictions . . . . . . . . . . . . . . . . .

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Chapter 4. Configuring Point-to-Point TCP/IP
Networks and Point-to-Point Connections . . .
PPP versus SLIP. . . . . . . . . . . .
Requirements for AS/400 SLIP. . . . . . .
Point-to-Point Request for Comments (RFC) .
Line Pools . . . . . . . . . . . . . .
Configuring Point-to-Point Network Connections

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OS/400 TCP/IP Configuration and Reference V4R4

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Configuring PPP Connection Profiles . . . . . . . . . . .
Accessing Point-to-Point functions through Operations Navigator .
Checking for existing PPP Connection Profiles . . . . . . . .
PPP Configuration Scenarios . . . . . . . . . . . . . .
Example: Configuring Windows 95/98 to an AS/400 using a PPP
Example: Connecting to the Internet using an ISP . . . . .
Example: Connecting two AS/400s using dial-on-demand . . .
Example: AS/400 Office-to-Office Scenarios . . . . . . . .
Example: Remote LAN Access with Transparent Subnetting . .
Example: Remote LAN Access with Dynamic Routing (RIP) . .
Monitoring Activity . . . . . . . . . . . . . . . . . .
Point-to-Point Jobs . . . . . . . . . . . . . . . . .
Connection Alternatives . . . . . . . . . . . . . . . .
Analog Phone Lines . . . . . . . . . . . . . . . .
Digital Data Service . . . . . . . . . . . . . . . . .
DDS . . . . . . . . . . . . . . . . . . . . . .
Switched-56 . . . . . . . . . . . . . . . . . . .
ISDN . . . . . . . . . . . . . . . . . . . . . .
T1/E1 . . . . . . . . . . . . . . . . . . . . . .
Fractional T1 . . . . . . . . . . . . . . . . . . .
Using an Asynchronous Modem or ISDN Terminal Adapter . . .
PPP ISDN Support . . . . . . . . . . . . . . . . .
Configuring SLIP Connection Profiles . . . . . . . . . . .
Writing Connection Dialog Scripts . . . . . . . . . . . .
Connection Script Considerations for SLIP . . . . . . . .
Connection Script Considerations for PPP . . . . . . . .
NLS Considerations. . . . . . . . . . . . . . . . .
Using SLIP with an Asynchronous Line Description . . . . . .
Connection Dialog Scripts . . . . . . . . . . . . . .
Configuring AS/400 Point-to-Point for SLIP . . . . . . . .
Monitoring Point-to-Point Activity . . . . . . . . . . . .
PPP/SLIP over *PPP . . . . . . . . . . . . . . . . .

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Chapter 5. Telnet Client . . . . . . . . . . . . . . .
5250 Full-Screen Mode Considerations . . . . . . . . .
TN5250—Start TCP/IP Telnet Command . . . . . . . .
TN5250—Screen Size . . . . . . . . . . . . . . .
3270 Full-Screen Mode Considerations . . . . . . . . .
TN3270—Start TCP/IP Telnet Command . . . . . . . .
Using a Display Station during Telnet 3270 Full-Screen Mode
TN3270—Screen Size . . . . . . . . . . . . . . .
TN3270—Cursor Select Key . . . . . . . . . . . .
TN3270—Messages . . . . . . . . . . . . . . .
TN3270—Handling Null Characters . . . . . . . . . .
VTxxx Full-Screen Mode Considerations . . . . . . . . .
Operational Differences . . . . . . . . . . . . . .
Keyboard Issues . . . . . . . . . . . . . . . . .
Screen Issues . . . . . . . . . . . . . . . . . .
VTxxx—Screen Size . . . . . . . . . . . . . . .
VTxxx—Character Attributes . . . . . . . . . . . .
VTxxx—Start TCP/IP Telnet Command. . . . . . . . .
Changing the VTxxx Keyboard Map . . . . . . . . . .
VTxxx—National Language Support . . . . . . . . . .
VTxxx—Multinational Mode . . . . . . . . . . . . .
VTxxx—National Mode . . . . . . . . . . . . . .
System Functions Available during a Telnet Client Session . .

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Chapter 6. Telnet Server . . . . . . . . . . . . . . . . . .
Setting Up the Telnet Server . . . . . . . . . . . . . . . . .
Determining Which Emulation Is Negotiated . . . . . . . . . . .
5250 Full-Screen Mode . . . . . . . . . . . . . . . . . . .
Examples of 5250 Server to 5250 Full-Screen Telnet Client . . . . .
3270 Full-Screen Mode . . . . . . . . . . . . . . . . . . .
Setting up for 3270 Full-Screen Mode . . . . . . . . . . . . .
Break Messages in 3270 Full-Screen Mode . . . . . . . . . . .
Input-Inhibited Light . . . . . . . . . . . . . . . . . . . .
Defining Capabilities for 3270 Devices . . . . . . . . . . . . .
VTxxx Full-Screen Mode . . . . . . . . . . . . . . . . . . .
Setting up for VTxxx Full-Screen Mode . . . . . . . . . . . .
VTxxx Automatic Wrap. . . . . . . . . . . . . . . . . . .
System Request Processing for VTxxx Sessions . . . . . . . . .
Error Conditions on 5250 Keyboard . . . . . . . . . . . . . .
Display Screens and VTxxx Support. . . . . . . . . . . . . .
VT220 Control Characters . . . . . . . . . . . . . . . . .
Some Practical Examples . . . . . . . . . . . . . . . . .
ASCII Line Mode . . . . . . . . . . . . . . . . . . . . . .
Setting up for ASCII Line Mode . . . . . . . . . . . . . . .
Telnet Printer Pass-Through Mode . . . . . . . . . . . . . . .
Setting Up for Telnet Printer Pass-Through Mode . . . . . . . . .
Telnet Printer Pass-Through Mode Server to Client Access Win95 Telnet
Client . . . . . . . . . . . . . . . . . . . . . . . .
Ending a Telnet Server Session . . . . . . . . . . . . . . . .
Starting Cascaded Telnet or DSPT Sessions . . . . . . . . . . .
Using System Request Options . . . . . . . . . . . . . . .
Telnet Scenarios for Establishing Cascaded Sessions . . . . . . .
System Request Processing—Scenarios . . . . . . . . . . . .
Using a Group Job—Scenario . . . . . . . . . . . . . . . .
Workstation Type Negotiations and Mappings . . . . . . . . . .
System API Enhancement . . . . . . . . . . . . . . . . . .
Dynamic Application Printing with TCP/IP . . . . . . . . . . . .
Exit Point Performance . . . . . . . . . . . . . . . . . . .
Work Management . . . . . . . . . . . . . . . . . . . .

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Chapter 7. File Transfer Protocol (FTP) Client . . . . . . . . . .
Functions Supported by FTP Client . . . . . . . . . . . . . . .
Functions Not Supported by FTP Client . . . . . . . . . . . . .
FTP Client and Server-Overview . . . . . . . . . . . . . . . .
Starting the FTP Client Session . . . . . . . . . . . . . . . .
Alternative Start Commands. . . . . . . . . . . . . . . . .
Connecting to Another Server without Ending the FTP Session . . . . .
Ending the FTP Client Session. . . . . . . . . . . . . . . . .
Transferring Files with File Transfer Protocol (FTP) . . . . . . . . .
Naming Format Indicator for AS/400 Names . . . . . . . . . . . .
File Naming for the Library File System (QSYS.LIB) . . . . . . . .
Names for Document Library Services (QDLS) Folders and Documents
Names for “root,” QOpenSys, QLANSrv and QFileSvr.400 File Systems
Localfile and Remotefile Parameters for FTP Client Subcommands . . .
Default File Names for Client Transfer Subcommands . . . . . . . .
FTP Client Subcommands . . . . . . . . . . . . . . . . . .
FTP Examples. . . . . . . . . . . . . . . . . . . . . .
FTP Considerations (for Both Client and Server) . . . . . . . . .

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FTP as Batch Job . . . . . . . . . . . . . . . . . . . . . . 269
Exit Points for FTP . . . . . . . . . . . . . . . . . . . . . . 277
Chapter 8. File Transfer Protocol (FTP) Server . . .
FTP Server-What It Does and Does Not Support . . .
Functions Supported by AS/400 FTP Server . . . .
Functions Not Supported by FTP Server . . . . .
Configuring FTP Servers . . . . . . . . . . . .
Starting FTP Servers . . . . . . . . . . . . .
Available FTP Servers . . . . . . . . . . . .
Ending FTP Servers . . . . . . . . . . . . .
Ending and Restarting FTP Server Jobs . . . . .
FTP Server Subcommands . . . . . . . . . . .
FTP Server Considerations . . . . . . . . . . .
FTP Server Considerations for Non-AS/400 Clients .
FTP Server NAMEFMT . . . . . . . . . . .
Exit Points for FTP Server Security and Anonymous FTP

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Chapter 9. Post Office Protocol (POP) Mail Server . . . . . .
How the POP Server Works. . . . . . . . . . . . . . . .
The POP Server and Client Access-based Mail . . . . . . . .
How to Get the POP Server Up and Running . . . . . . . . .
Setting Up Your System and Users . . . . . . . . . . . . .
Adding POP Mail Users to the System Distribution Directory . . .
POP Mailboxes . . . . . . . . . . . . . . . . . . .
Setting Up Standard POP Mail Clients . . . . . . . . . . .
Setting Up Client Access-Based Mail Clients . . . . . . . .
Configuring the POP Server. . . . . . . . . . . . . . . .
Configuring POP for Client Access-Based Mail Users . . . . . .
Removing POP Mail Users from the System. . . . . . . . .
Setting the Number of SNA Servers . . . . . . . . . . . .
Starting the POP Server . . . . . . . . . . . . . . . . .
Ending the POP Server . . . . . . . . . . . . . . . . .
Supported POP Verbs . . . . . . . . . . . . . . . . . .
How the POP Server Uses the Mail Server Framework. . . . . .
Exchanging Mail with OfficeVision . . . . . . . . . . . . .
Configuring Both POP and SMTP . . . . . . . . . . . .
Using *ANY Support with the POP Server . . . . . . . . .
MIME Mail Sent To OfficeVision . . . . . . . . . . . . .
Long Line Conversion . . . . . . . . . . . . . . . . .
Data Area Values. . . . . . . . . . . . . . . . . . .
MIME Content Types . . . . . . . . . . . . . . . . .
Supported Content Types of the POP Server . . . . . . . .
How the File Name is Derived . . . . . . . . . . . . . .
MIME Content Types . . . . . . . . . . . . . . . . .
What Happens When You Send OfficeVision Mail to POP Clients . .
Setting Up MIME Headers to Differentiate between Recipients . .
Sending MIME (POP Server) Mail across a SNADS Network . . .
How SNADS Tunneling Works . . . . . . . . . . . . . .
How to Configure System Distribution Directory Entries for SNADS
Tunneling. . . . . . . . . . . . . . . . . . . . .
Address Types . . . . . . . . . . . . . . . . . . . .
AS/400 Address Book . . . . . . . . . . . . . . . . . .
The Address Book Cache . . . . . . . . . . . . . . .
ASCII-EBCDIC Conversion and National Language Support . . . .

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EBCDIC-to-ASCII Conversion . . . . . . . . . . . . . . . . . . 314
ASCII-to-EBCDIC Conversion . . . . . . . . . . . . . . . . . . 315
Chapter 10. Workstation Gateway Server . . . . . . . . . . .
Accessing Workstation Gateway Functions through Operations Navigator
Starting the Workstation Gateway Server . . . . . . . . . . . .
Automatically Starting the Workstation Gateway Server. . . . . . .
Ending the Workstation Gateway Server . . . . . . . . . . . .
Configuring the Workstation Gateway Server . . . . . . . . . .
Managing Virtual Devices for the Client . . . . . . . . . . . .
Changing the Workstation Gateway Configuration. . . . . . . . .
Number of Clients per Server (NBRCLT) . . . . . . . . . . .
Inactivity Timeout (INACTTIMO) . . . . . . . . . . . . . .
Data Request Timeout (DTARQSTIMO) . . . . . . . . . . .
Display Sign-on Panel (DSPSGN) . . . . . . . . . . . . .
Access Logging (ACCLOG) . . . . . . . . . . . . . . . .
Top Banner URL (TOPBNRURL) . . . . . . . . . . . . . .
Bottom Banner URL (BOTBNRURL). . . . . . . . . . . . .
Help Panel URL (HLPPNLURL) . . . . . . . . . . . . . .
Coded Character Set Identifier (CCSID) . . . . . . . . . . .
Server Mapping Tables (TBLWSGOUT) and (TBLWSGIN) . . . . .
Workstation Gateway Exit Point for Accessing a User Profile Directly .
Granting Access to the Web Browser Online Help Information . . . .
Customizing Web Browser Online Help Information . . . . . . .
Managing the Access Log . . . . . . . . . . . . . . . . .
The QATMTLOG File . . . . . . . . . . . . . . . . . .
Accessing the Workstation Gateway from a Web Browser. . . . .
Security . . . . . . . . . . . . . . . . . . . . . . .
Workstation Gateway — Requirements . . . . . . . . . . .
How the 5250 Display is Formatted for the Workstation Gateway . .
Configuration Examples . . . . . . . . . . . . . . . . .
Online Help Information . . . . . . . . . . . . . . . . .

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330
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330
332
334
335
335
337
338

Chapter 11. Line Printer Requester (LPR) . . . . . . . . . . . . .
LPR Command . . . . . . . . . . . . . . . . . . . . . . .
Client (LPR) and Server (LPD) Relationship . . . . . . . . . . . . .
Configuration Requirements for LPR . . . . . . . . . . . . . . .
Sending a Spooled File (LPR) . . . . . . . . . . . . . . . . . .
Step 1 — Locate the Spooled File that you Want to Send . . . . . . .
Step 2 — Start the Spooled File Transfer . . . . . . . . . . . . .
Sending Spooled Files to an AS/400 at V2R3 or V3R0M5. . . . . . .
How the System Sends a Spooled File from an AS/400 System to Another
AS/400 System . . . . . . . . . . . . . . . . . . . . .
How the System Sends a Spooled File from an AS/400 System to a
Non-AS/400 System . . . . . . . . . . . . . . . . . . . .
Transformation of Spooled Files . . . . . . . . . . . . . . . .
Sending Spooled File — Tips . . . . . . . . . . . . . . . . .
Sending Large Spooled Files . . . . . . . . . . . . . . . . .
Printer Pass-Through . . . . . . . . . . . . . . . . . . . . .
Setup . . . . . . . . . . . . . . . . . . . . . . . . . .
Starting Printer Pass-Through . . . . . . . . . . . . . . . . .
Configuring for a RISC System/6000 System — Scenario . . . . . . . .
Setting Up for LPD on the RISC System/6000 System — Scenario . . .
Configuring Device and Virtual Printer for AIX Printing . . . . . . . .
Verifying LPD Started on the RISC System/6000 System . . . . . . .
Verifying Your Configuration on the RISC System/6000 System. . . . .

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Print Services Facility/6000 Function . . . . . . . . . . . . . . . . 360
Configuring PSF/6000 Function . . . . . . . . . . . . . . . . . 360
Verifying Your Configuration of PSF/6000 . . . . . . . . . . . . . . 361
Chapter 12. Line Printer Daemon (LPD) . . . . . . . . . . . .
Configuring for Line Printer Daemon (LPD) . . . . . . . . . . . .
How the Destination System Receives a Spooled File . . . . . . . .
How an AS/400 System Receives a Spooled File from Another AS/400
System . . . . . . . . . . . . . . . . . . . . . . .
How an AS/400 System Receives a Spooled File from a Non-AS/400
System . . . . . . . . . . . . . . . . . . . . . . .
How Spooled Files are Named on the Destination AS/400 . . . . .
Starting an LPD Server Job . . . . . . . . . . . . . . . . .
Ending an LPD Server Job . . . . . . . . . . . . . . . . .
Attributes of the Received Spooled File . . . . . . . . . . . .
User Profile Library Lists . . . . . . . . . . . . . . . . . .
How the Ownership of Spooled Files Is Determined . . . . . . . .
How an LPD Server Selects an Output Queue for a File . . . . . .
How Authority for Putting Spooled Files on Output Queue is Determined
Using LPD to Print ASCII Files . . . . . . . . . . . . . . . .
Using LPD to Print ASCII Files Converted to EBCDIC . . . . . . .
Authority Required to Receive Spooled Files . . . . . . . . . .

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375

Chapter 13. BOOTP Server . . . . . . . . . . . . . .
Accessing BOOTP Functions through Operations Navigator . . .
Starting the BOOTP Server . . . . . . . . . . . . . . .
Automatically Starting the BOOTP Server. . . . . . . . . .
Ending the BOOTP Server . . . . . . . . . . . . . . .
Configuring the BOOTP Server . . . . . . . . . . . . .
Changing BOOTP Attributes. . . . . . . . . . . . . . .
Working with the BOOTP Table . . . . . . . . . . . . .
Adding IBM Network Stations to an Existing BOOTP Environment.
Adding Network Stations with the Command Line Interface . .
Adding Network Stations with Operations Navigator . . . . .

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Chapter 14. TFTP Server . . . . . . . . . . . . . .
Accessing TFTP Functions through Operations Navigator . . .
Starting the TFTP Server . . . . . . . . . . . . . . .
Automatically Starting the TFTP Server . . . . . . . . .
Ending the TFTP Server . . . . . . . . . . . . . . .
Changing TFTP Attributes . . . . . . . . . . . . . .
Server and Client Ports . . . . . . . . . . . . . . .
TFTP Extensions . . . . . . . . . . . . . . . . . .
TFTP Transfer Size Option . . . . . . . . . . . . .
TFTP Subnet Broadcast Option . . . . . . . . . . .
Configuring TFTP for Clients other than IBM Network Station

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Chapter 15. RouteD Server . . . . . . .
Accessing RouteD Functions through Operations
Starting the RouteD Server . . . . . . . .
Automatically Starting the RouteD Server . . .
Ending the RouteD Server . . . . . . . .
Configuring the RouteD Server . . . . . .
Working with RouteD Configuration . . . . .
RouteD Configuration Scenario . . . . . .
RIP_INTERFACE Statement . . . . . . .

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394

Contents

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Navigator
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Supply Values . . . . .
DIST_ROUTES_IN . . .
Metric . . . . . . . .
Community . . . . . .
Additional Parameters . .
Changing RouteD Attributes .

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Chapter 16. REXEC Server . . . . . . . . . . . .
Accessing REXEC Functions through Operations Navigator .
Starting the REXEC Server from the Command Line Interface
Automatically Starting the REXEC Server . . . . . . . .
Ending the REXEC Server . . . . . . . . . . . . .
Changing Attributes . . . . . . . . . . . . . . . .
REXEC Command Considerations . . . . . . . . . .
Selecting a Command Processor . . . . . . . . . . .
REXEC Connection Usage . . . . . . . . . . . . .
For AS/400 CL command processing . . . . . . . .
For Qshell and spawned path command processing . . .
Spooled Output Considerations . . . . . . . . . . .
Client Considerations . . . . . . . . . . . . . . .
REXEC Server Jobs and Job Names . . . . . . . . .
Creating REXEC Server Spooled Job Logs . . . . . . .
Exit Points for Controlling REXEC Server . . . . . . . .

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Chapter 17. DHCP Server . . . . . . . . . . . . . . . . .
DHCP Overview . . . . . . . . . . . . . . . . . . . . .
What is DHCP? . . . . . . . . . . . . . . . . . . . .
Planning for DHCP . . . . . . . . . . . . . . . . . . .
Setting Up a DHCP Network . . . . . . . . . . . . . . .
Specifying DHCP Options . . . . . . . . . . . . . . . .
Request for Comment and Internet Draft Documents . . . . . .
Accessing DHCP Functions through Operations Navigator . . . . .
Starting and Ending the DHCP Server from the Command Line Interface
Starting the DHCP Server . . . . . . . . . . . . . . . .
Automatically Starting the DHCP Server . . . . . . . . . . .
Ending the DHCP Server . . . . . . . . . . . . . . . . .
Changing DHCP Attributes . . . . . . . . . . . . . . . . .
Exit Points for a DHCP Server . . . . . . . . . . . . . . . .
Examples of DHCP Configurations . . . . . . . . . . . . . .
Configuring DHCP for a Local Area Network. . . . . . . . . .
Configuring DHCP for a Local Area Network with a Router . . . .
Using DHCP to Configure Clients Attached to a Twinax Workstation
Controller. . . . . . . . . . . . . . . . . . . . . .
Migrating an Existing BOOTP Configuration . . . . . . . . . . .
DHCP Relay Agent . . . . . . . . . . . . . . . . . . . .
Adding Network Stations . . . . . . . . . . . . . . . . . .

Chapter 18. AS/400 Domain Name System (DNS) . . . . . . . . . . . 421
How DNS works . . . . . . . . . . . . . . . . . . . . . . . . 421
Additional DNS documentation. . . . . . . . . . . . . . . . . . . 422
Chapter 19. Client SOCKS Support . . . . . . . . . . . . . . . . 423
Accessing SOCKS Functions through Operations Navigator . . . . . . . . 423
Chapter 20. TCP/IP Performance . . . . . . . . . . . . . . . . . 425
*BASE Pool Size . . . . . . . . . . . . . . . . . . . . . . . . 425

OS/400 TCP/IP Configuration and Reference V4R4

TCP/IP Jobs . . . . . . . . . . . . . .
TCP/IP Protocol Support Provided by IOP . . .
Merge Host Table Performance . . . . . . .
Running TCP/IP Only: Performance Considerations

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Chapter 21. TCP/IP Problem Analysis . . . . . . . . .
General TCP/IP Problems . . . . . . . . . . . . . .
PING Command Considerations . . . . . . . . . . .
Working with the Job Log and Message Queues . . . . .
Determining Problems for SNMP . . . . . . . . . . . .
Determining Problems for Serial Line Internet Protocol (SLIP) .
Problem: SLIP Connection Is Failing . . . . . . . . .
Problem: SLIP Job ’Hung’ with STRSSN Status . . . . .
Problem: SLIP Connection Complete but Unable to PING . .
Materials Required for Reporting SLIP Problems . . . . .
Determining Problems with TELNET. . . . . . . . . . .
Materials Needed when Reporting TELNET Problems . . .
Determining Problems with FTP . . . . . . . . . . . .
Materials Required for Reporting FTP Problems . . . . .
Tracing FTP Server . . . . . . . . . . . . . . . .
Tracing FTP Client . . . . . . . . . . . . . . . .
Getting a Copy of an FTP Server Job Log . . . . . . .
Determining Problems for SMTP . . . . . . . . . . . .
Determining Problems for SMTP When Using OfficeVision .
Determining Problems for SMTP Without Using OfficeVision .
Tracing SMTP Distributions . . . . . . . . . . . . .
Materials Required for Reporting SMTP Problems . . . .
Cleaning Up Unprocessed SMTP Distributions . . . . . .
Determining Problems with the POP Server . . . . . . . .
Problems with Mail Delivery . . . . . . . . . . . . .
Problem Determination Flows . . . . . . . . . . . .
Determining Problems with the Workstation Gateway Server. .
First Failure Data Capture (FFDC) . . . . . . . . . .
Determining Problems for DNS Server . . . . . . . . . .
Problem Determination Tools . . . . . . . . . . . .
Problem Determination Flows . . . . . . . . . . . .
Determining Problems for LPR . . . . . . . . . . . . .
LPR Command Considerations . . . . . . . . . . .
Common Error Messages . . . . . . . . . . . . .
Determining Problems for LPD . . . . . . . . . . . . .
Materials Required for Reporting LPD Problems . . . . .
Determining Problems with REXEC . . . . . . . . . . .
Materials Required for Reporting REXEC Problems . . . . .
Getting a Copy of an REXEC Server Job Log . . . . . . .
Tracing the REXEC Server . . . . . . . . . . . . . .
Tracing TCP/IP Protocol Layer Problems . . . . . . . . .
APPC Over TCP/IP Debugging Capabilities . . . . . . . .
Tracing APPC over TCP/IP Problems . . . . . . . . .
Collecting a Communications Trace . . . . . . . . . . .
Planning to Set up a Trace . . . . . . . . . . . . .
Starting a Communications Trace. . . . . . . . . . .
Stopping a Communications Trace . . . . . . . . . .
Formatting and Saving the Communications Trace . . . .
Verifying the Contents of the Communications Trace. . . .
Using the Product Activity Log for TCP/IP Problem Analysis . .

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503

Contents

Appendix A. Configuring a Physical Line for TCP/IP Communication
Configuration Steps . . . . . . . . . . . . . . . . . . . .
Creating the Line Description . . . . . . . . . . . . . . .
Setting the Maximum Transmission Unit . . . . . . . . . . .
Determining the Maximum Size of Datagrams . . . . . . . . .

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505
506
506
507
507

Appendix B. TCP/IP Security . . . . . .
TCP/IP Command Security . . . . . . .
Object Security for Network Configuration.
IBM-Written Programs Security . . . .
Customer-Written Programs Security . .
User-Supplied Mapping Tables . . . . .

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509
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513
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514
514

Appendix C. Mapping Tables Associated with TCP/IP Function
National Language Support Mapping . . . . . . . . . . .
Summary of Mapping Tables . . . . . . . . . . . . . .
Creating ASCII and EBCDIC Mapping Tables . . . . . . . .
Creating a Source Member for Incoming Data . . . . . . .
Creating a Source Member for Outgoing Data . . . . . . .
Creating a Mapping Table . . . . . . . . . . . . . .
Specifying User-Defined ASCII and EBCDIC Mapping Tables .
Creating 3270 Mapping Tables . . . . . . . . . . . . . .
Creating a Source Member for Incoming Data . . . . . . .
Creating a Source Member for Outgoing Data . . . . . . .
Creating a Mapping Table . . . . . . . . . . . . . .
Using Mapping Tables for 3270 Full-Screen Mode . . . . .
Reading a Mapping Table . . . . . . . . . . . . . . .
Changing a Mapping Table . . . . . . . . . . . . . . .
Sample Mappings . . . . . . . . . . . . . . . . . .
EBCDIC and ASCII Character Sets . . . . . . . . . . . .
USA Standard 7-Bit ASCII Character Set . . . . . . . . .
EBCDIC-to-ASCII Mapping Table . . . . . . . . . . . .
ASCII-to-EBCDIC Mapping Table . . . . . . . . . . . .
ASCII Line Drawing Character Set . . . . . . . . . . .

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530

Appendix D. TELNET 3270 Keyboard Mappings . . . . . . . . . . . 531
AS/400 CL Programs for the CHGKBDMAP Command . . . . . . . . . . 531
Appendix E. TCP/IP Application Exit Points and Programs . . . .
TCP/IP Exit Points and Exit Programs . . . . . . . . . . . . .
OS/400 Registration Facility . . . . . . . . . . . . . . . . .
TCP/IP Application Exit Points . . . . . . . . . . . . . . . .
Creating Exit Programs . . . . . . . . . . . . . . . . . .
Adding Your Exit Program to the Registration Facility . . . . . .
Removing Exit Programs . . . . . . . . . . . . . . . . .
TELNET Exit Points. . . . . . . . . . . . . . . . . . . .
Telnet Device Initialization Exit Program . . . . . . . . . . .
TELNET Device Termination Exit Program . . . . . . . . . . .
Required Parameter Group . . . . . . . . . . . . . . . .
Exit Point Interfaces for TCP/IP Application Exit Points . . . . . . .
TCP/IP Application Request Validation Exit Point Interface . . . .
TCP/IP Application Server Logon Exit Point Interface . . . . . .
Remote Execution Server Command Processing Selection Exit Point
File Transfer Protocol (FTP) Exit Points . . . . . . . . . . . .
Considerations and Recommendations for FTP Exit Programs . . .
FTP Exit Program—Scenario . . . . . . . . . . . . . . .

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554

Sample FTP Server Logon Exit Program (C Language) . . . . .
Anonymous FTP . . . . . . . . . . . . . . . . . . . . .
Sample Scenario for Anonymous FTP . . . . . . . . . . . .
Workstation Gateway Server (WSG) Exit Point . . . . . . . . . .
Workstation Gateway Server Sign-on Exit Point Interface (QAPP0100)
Required Parameters . . . . . . . . . . . . . . . . .
Descriptions of Required Parameters for the WSG Exit Point Interface
(QAPP0100) . . . . . . . . . . . . . . . . . . . .
Using a WSG exit progam to bypass the AS/400 Sign-on Display . .
Sample WSG Server Logon Exit Program . . . . . . . . . .

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Notices . . . . . . . . . . . . . . . . . . . . . . . . . . . 595
Programming Interface Information . . . . . . . . . . . . . . . . . 596
Trademarks . . . . . . . . . . . . . . . . . . . . . . . . . . 596
Bibliography . . . . . . . . .
Client Access Books . . . . . .
Communications Manuals . . . .
Integrated Netfinity Server Manuals .
Internet Connection Server Manuals.
Programming Manuals . . . . . .
Security . . . . . . . . . . .
System Manuals . . . . . . . .
Systems Network Architecture (SNA)
Request For Comments (RFC). . .
Other Information . . . . . . .

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Display
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Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . 605
Readers’ Comments — We’d Like to Hear from You. . . . . . . . . . 635

Contents

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OS/400 TCP/IP Configuration and Reference V4R4

About TCP/IP Configuration and Reference (SC41-5420)
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This book contains information about configuring and using Transmission Control
Protocol/Internet Protocol (TCP/IP) and writing programs to the TCP/IP application
interface. Some topics have moved to the Information Center. See “TCP/IP Topics
in the Information Center”.
TCP/IP Packaging:

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|
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When you purchase OS/400, the ordering system automatically places an order for
the TCP/IP Utilities Licensed Program (LP). The TCP/IP Utilities LP is shipped with
OS/400 at no additional charge. However, you must install the TCP/IP Utilities LP
separately by using normal installation support.

TCP/IP Topics in the Information Center

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These related topics are described in the AS/400e Information Center instead of in
this book:
Under the TCP/IP heading:
v Getting started with TCP/IP
v Connecting two systems with Point-to-Point Protocol (PPP)

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v Logging on to a remote computer (Telnet)
v Managing host names with Domain Name System (DNS)
v Sending and receiving e-mail
v Transferring files with File Transfer Protocol (FTP)
Under the Internet and Secure Networks heading:
v Client SOCKets
v IP packet security

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v Virtual Private Network (VPN)

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You can access the Information Center from the AS/400e Information Center
CD-ROM (English version: SK3T-2027) or from one of these Web sites:

|
|

To find out more about the Information Center, see “Prerequisite and related
information” on page xvii.

http://www.as400.ibm.com/infocenter
http://publib.boulder.ibm.com/pubs/html/as400/infocenter.htm

Who should read this book
This book is intended for the following audience:
v Users who configure TCP/IP and its associated applications
v Users who use TCP/IP functions or commands
v Programmers who write to the sockets applications programming interface, or
API. For details on the AS/400 sockets API see System API Reference,
SC41-5801-03. For additional information about sockets, including sample
programs, see the Sockets Programming, SC41-5422-03 book. For information

about firewall concepts and an IBM firewall product for the AS/400 system, see
the Getting Started with IBM Firewall for AS/400, SC41-5424-02 book or go to
http://www.as400.ibm.com/firewall.
You need to be familiar with, or have previous experience in, the following areas:
v TCP/IP. If this is your first experience with TCP/IP, consider reading some of the
material listed in the Bibliography.
v AS/400 menus and commands.
v Operations Navigator. Some of the applications require the use of this function.
v Writing applications on the AS/400 system. If you plan to write programs to the
TCP/IP application program interface, you must know how to write applications
on the AS/400 system.

AS/400 Operations Navigator
AS/400 Operations Navigator is a powerful graphical interface for Windows clients.
With AS/400 Operations Navigator, you can manage and administer your AS/400
systems from your Windows desktop.
You can use Operations Navigator to manage communications, printing, database,
security, and other system operations. Operations Navigator includes Management
Central for managing multiple AS/400 systems centrally.
Figure 1 shows an example of the Operations Navigator display:

Figure 1. AS/400 Operations Navigator Display

This new interface has been designed to make you more productive and is the only
user interface to new, advanced features of OS/400. Therefore, IBM recommends
that you use AS/400 Operations Navigator, which has online help to guide you.
While this interface is being developed, you may still need to use a traditional
emulator such as PC5250 to do some of your tasks.

Installing Operations Navigator
To use AS/400 Operations Navigator, you must have Client Access installed on your
Windows PC. For help in connecting your Windows PC to your AS/400 system,
consult Client Access Express for Windows - Setup, SC41-5507-00.

xvi

OS/400 TCP/IP Configuration and Reference V4R4

AS/400 Operations Navigator is a separately installable component of Client Access
that contains many subcomponents. If you are installing for the first time and you
use the Typical installation option, the following options are installed by default:
v Operations Navigator base support
v Basic operations (messages, printer output, and printers)
To select the subcomponents that you want to install, select the Custom installation
option. (After Operations Navigator has been installed, you can add subcomponents
by using Client Access Selective Setup.)
1. Display the list of currently installed subcomponents in the Component
Selection window of Custom installation or Selective Setup.
2. Select AS/400 Operations Navigator.
3. Select any additional subcomponents that you want to install and continue with
Custom installation or Selective Setup.
After you install Client Access, double-click the AS400 Operations Navigator icon
on your desktop to access Operations Navigator and create an AS/400 connection.

Prerequisite and related information
Use the AS/400 Information Center as your starting point for looking up AS/400
technical information. You can access the Information Center from the AS/400e
Information Center CD-ROM (English version: SK3T-2027) or from one of these
Web sites:
http://www.as400.ibm.com/infocenter
http://publib.boulder.ibm.com/pubs/html/as400/infocenter.htm

The AS/400 Information Center contains important topics such as logical
partitioning, clustering, Java, TCP/IP, Web serving, and secured networks. It also
contains Internet links to Web sites such as the AS/400 Online Library and the
AS/400 Technical Studio. Included in the Information Center is a link that describes
at a high level the differences in information between the Information Center and
the Online Library.
For a list of related publications, see the “Bibliography” on page 599.

How to send your comments
Your feedback is important in helping to provide the most accurate and high-quality
information. If you have any comments about this book or any other AS/400
documentation, fill out the readers’ comment form at the back of this book.
v If you prefer to send comments by mail, use the readers’ comment form with the
address that is printed on the back. If you are mailing a readers’ comment form
from a country other than the United States, you can give the form to the local
IBM branch office or IBM representative for postage-paid mailing.
v If you prefer to send comments by FAX, use either of the following numbers:
– United States and Canada: 1-800-937-3430
– Other countries: 1-507-253-5192
v If you prefer to send comments electronically, use one of these e-mail addresses:
– Comments on books:
About TCP/IP Configuration and Reference (SC41-5420)

xvii

RCHCLERK@us.ibm.com
IBMMAIL, to IBMMAIL(USIB56RZ)
– Comments on the AS/400 Information Center:
RCHINFOC@us.ibm.com
Be sure to include the following:
v The name of the book.
v The publication number of the book.
v The page number or topic to which your comment applies.

xviii

OS/400 TCP/IP Configuration and Reference V4R4

Chapter 1. TCP/IP on AS/400
Transmission Control Protocol/Internet Protocol (TCP/IP) refers to a specific set
of protocols that allows computers to share resources and exchange information in
a network. Because TCP and IP are two of the best-known protocols in this set, the
term TCP/IP has become the standard name for the whole family.
TCP/IP support on AS/400 contains many of the commonly used protocols in the
TCP/IP family. Some of the protocols provide low-level and high-level data delivery
functions that are needed by several applications.
Most applications require Internet Protocol (IP), Transmission Control Protocol
(TCP), and User Datagram Protocol (UDP), which are low-level functions. High-level
functions or applications provide services such as file transfer, mail, and remote
logon. File Transfer Protocol (FTP), Simple Mail Transfer Protocol (SMTP), and
TELNET are examples of high-level protocols.
TCP/IP is used to interconnect networks on a global basis across universities,
research institutions, businesses and industries, and military installations. The term
Internet applies to this entire set of interconnected networks. Because these
networks are interconnected, information is sent from one to another as security
restrictions permit. The Internet is governed by a central authority, which is
responsible for assigning network addresses to new users and subnetworks. Many
smaller private networks around the world use TCP/IP protocols, without connecting
to the Internet. TCP/IP provides a good solution for these smaller networks.

Linking Networks Together
Networks are linked together by sharing a common node system that routes
packets from one network to another. This common system is often referred to as
an IP router, or simply as a router. A router is a computer that directly attaches to
two or more IP networks and, as its name implies, routes packets from one network
to the other.
The networks connected by a router may use the same or different physical
network protocols. For example, one network could be an Ethernet LAN, and the
other might be a token ring. If necessary, the router transfers packets from one
network protocol to another. In this way, the system passes the packets from one
router to another. The system continues transfer attempts until it delivers the packet
to the final destination system directly across one physical network.
The terms gateway and router are often used interchangeably, particularly in this
publication. However, be aware that gateway often implies a more specialized
system. A gateway typically performs extra functions beyond the mere routing of
packets. For example, a gateway might provide a firewall.
You can use a bridge to connect networks. A bridge connects two or more networks
at the physical network level by forwarding data from one network to another. A
bridge differs from IP routers because a bridge uses physical addresses instead of
internet addresses. A bridge does not have an assigned internet address while an
IP router does. Therefore, a bridge is transparent in the TCP/IP network. A set of
bridged networks (or segments) appears and acts as a single physical network.

A network to which a node system is physically connected is a local network for
that system. A network that a system reaches only after passing through one or
more IP routers is called a remote network.

Internetwork Communications
An internetwork or internet is a collection of packet-switched physical networks that
are connected by routers to form a single, large virtual network. Simply, it is a
network of networks. Packets are units of data that are sent across
packet-switched networks. All nodes in the internet communicate as if they are on
the same physical network, regardless of their specific hardware or specific
software architecture. This cooperation among otherwise incompatible networks and
systems is known as interoperability.
Figure 2 shows how networks can be connected in an internet.

Figure 2. An Internetwork

The network connection of each node on an internetwork is assigned a unique
address. This internet address differs from a physical hardware address in that the
hardware address is often preset by the manufacturer, whereas you can assign or
reassign an internet address by standard conventions. Also, internet addresses are
in a standard form, while different hardware types use different address lengths and
formats.

Internet Addresses
Each node on a network is known as a host and has a unique address called an
internet address. This address is a 32-bit integer. An address is expressed in the
form nnn.nnn.nnn.nnn, where each field is the decimal representation of one byte,
or 8 bits, of the address. For example, the address whose hexadecimal
representation is X'82638001' is expressed as 130.99.128.1.

OS/400 TCP/IP Configuration and Reference V4R4

Within your own networks, you can assign your own addresses. However, if you
want to connect to the Internet, then your network addresses and domain names
that need to be visible on the Internet must be officially assigned by a central
authority. The authority at the time of this writing is Network Solutions, Inc. The
address is:
Network Solutions, Inc.
ATTN: InterNIC Registration Services
505 Huntmar Park Drive
Herndon, VA 20170
USA
1-703-742-4777
FAX: 1-703-742-9552
E-mail: hostmaster@internic.net
URL: http://rs.internic.net/
Information about how to register a new domain name through the InterNIC is found
at the URL address which is listed above. This address contains registration tools
and forms for online registering, and an overview on domain name registration.
The Internet Assigned Numbers Authority, or IANA, has allocated a block of Internet
network addresses for use only in private networks, or intranets. The addresses are
dispensed through the InterNIC registration process. IANA guarantees that the
addresses within this range are not used as valid host internet addresses on the
Internet. The reserved addresses within this block are as follows:
10.0.0.0
172.16.0.0
192.168.0.0

10.255.255.255
172.31.255.255
192.168.255.255

Accessing the Internet
To obtain Internet access you must purchase it through an Internet Service Provider
(ISP). If you need assistance, the InterNIC provides you with contact information for
ISPs in the United States and other countries. See “Internet Addresses” on page 2
for address information to contact the InterNIC Registration Services.
Once you have selected an ISP to work with, the ISP obtains an internet address
for you. If you choose not to connect to the Internet through an ISP but plan to do
so directly, you still need to apply to the InterNIC for a domain address and an IP
network ID. However, in order to apply to the InterNIC without the assistance of an
ISP, you must be either a service provider or a large global corporation.
IBM also offers ISP services as part of its Internet Connection family of service
offerings. To contact IBM within the United States, call 1-800-IBM-4YOU
(1-800-426-4698), or you may call your local IBM office.
In addition, the following IBM Redbooks offer more information about choosing an
Internet Service Provider:
v Cool Title About the AS/400 and the Internet, SC24-4815
v Accessing the Internet, SG24-2597
v Using the Information Super Highway, GG24-2499

Chapter 1. TCP/IP on AS/400

IP Security
After choosing an Internet Service Provider (ISP) and setting up your Internet
connection, you will also need to create and implement a security policy. Such a
policy can be used to incorporate the rules governing computer resources and
communications resources within your organization. The inherent security features
of AS/400, when properly configured, provide you with the ability to minimize many
risks. However, when you connect to the Internet, you should consider additional
security measures to further ensure the safety of your AS/400 system and your
network.
The first step in developing a security policy is that you understand the risks that
are imposed by each service you intend to use or provide. Once you have identified
these risks and created a security policy in response to them, you will be prepared
to take the necessary steps to enforce them. To name a few, these steps may
include employee training and the purchase of additional hardware or software.
As you create a security policy and outline security objectives for your organization,
the following resources may be helpful:
v The book, Tips and Tools for Securing Your AS/400, SC41-5300-03
v The AS/400e Information Center offers a list of current topics about using the
Internet. Look there for information about IP packet filtering and network address
translation (NAT). It is located at the following URL address:

|
|
|
|
|

http://publib.boulder.ibm.com/html/as400/infocenter.html

Classes of Networks
Each internet address is comprised of a pair of numbers that correspond to its
network address, or network ID and host address, or host ID. The network ID
represents the network within the internet, and the host ID specifies an individual
host or router within the network.
internet address =

The value of the first byte of the Internet address specifies how the Internet address
should be separated into its network and host part, as shown in Table 1. The 4-byte
address is divided between network ID and host ID in five different ways or classes.
The five classes of Internet addresses are: A, B, C, D, and E. Also shown is the
maximum number of hosts per network for each class.
Table 1. Classes of Networks

Network Class

Network ID

Host ID

Maximum Number
of Hosts per
Network Class

Class A

0 to 127

First byte

Last 3
bytes

16 777 214

Class B

128 to 191

First 2 bytes

Last 2
bytes

65 534

Class C

192 to 223

First 3 bytes

Last byte

254

Class D

224 to 239

Multicast

240 to 255

Reserved for future
use

Class E

Range of First
Byte

OS/400 TCP/IP Configuration and Reference V4R4

Table 1. Classes of Networks (continued)

Network Class

Range of First
Byte

Network ID

Host ID

Maximum Number
of Hosts per
Network Class

Notes:
1. Although 127 is a class A network ID, it is reserved for loopback addresses and cannot
be assigned.
2. Not supported by AS/400 except for the limited broadcast address of 255.255.255.255.

If the first byte of an Internet address is in the range 0 to 127, it is a Class A
network. These are very large networks. The host IDs can range from 0.0.1 to
255.255.254, which allows for a maximum of 16,777,214 hosts. An example of a
class A Internet address is 9.5.1.2. The network ID is 9 and the host ID is 5.1.2.
If the first byte of an Internet address is in the range 128 to 191, it is a Class B
network. These are medium-size networks. The host IDs can range from 0.1 to
255.254, which allows for a maximum of 65,534 hosts. An example of a class B
Internet address is 150.244.1.241. The network ID is 150.244 and the host ID is
1.241.
If the first byte of an Internet address is in the range 192 to 223, it is a Class C
network. These are relatively small networks. The host IDs can range from 1 to 254,
which allows for a maximum of 254 hosts. An example of a class C Internet
address is 221.6.1.244. The network ID is 221.6.1 and the host ID is 244.
If the first byte of an Internet address is in the range 224 to 239, it is a Class D
network. These addresses identify multicast networks. The first 4 bits in a class D
Internet address identify the Internet address as a multicast address. The rest of the
bits (28) identify a specific multicast group.
If the first byte of an Internet address is in the range 240 to 255, it is a Class E
network. These addresses are undefined and experimental at this time. AS/400
does not support class E Internet addresses except for the limited broadcast
address of 255.255.255.255.
Understanding network classes and how the Internet address is divided into
different classes is important for the discussion of subnetworks in the following
topic.

IP Subnets
An IP subnet is the division or split of a TCP/IP network. When you divide an IP
network into multiple subnets, you avoid having to request additional IP network
addresses and alleviate the waste of existing addresses. ″Subnetting″ is frequently
performed on class A and B internetworks because they are larger and contain
more available host address space.
Also worth noting is the fact that subnets can be assigned locally and the process
of subnetting can remain transparent to remote networks.

Chapter 1. TCP/IP on AS/400

Subnetworks and Subnet Masks
A class A, B, or C network can be further divided into multiple smaller networks that
are called subnetworks. These smaller networks are identified or addressed by a
subnet ID. With an Internet address of any class we can subdivide the host ID bits
to provide identification of the subnet ID. The subnetwork is identified by combining
the network ID and subnet ID. This combining of the network ID and subnet ID is
defined as a subnet mask.
A subnet mask further specifies for the host the exact number of bits that are to be
used for the subnet ID and the number to be used for the host ID. Overall, subnet
masks make it easier to divide a single network without wasting internet addresses
and as a result, increase the performance of the network.
For example, consider a class B internet address that has a network ID portion
equal to 144.22. This class B address has 16 bits allocated for the network ID and
16 bits allocated for the host ID as shown in Figure 3:

Figure 3. Standard Class B

If the high-order byte of the host ID portion of the class B internet address is used
for a subnet ID, then the host ID can be divided into an 8-bit subnet ID and an 8-bit
host ID as shown in Figure 4:

Figure 4. Subnetted Class B

The class B 144.22 network, using this identification of the subnet ID, can be
divided into 254 subnetworks ranging from 144.22.1 through 144.22.254.

Figure 5. Subnetted Class B with Subnetworks

The subnet mask that identifies the subnetwork in this example would be
255.255.255.0.
Therefore, an internet address can be shown as consisting of the following:
internet address =

OS/400 TCP/IP Configuration and Reference V4R4

Note: The subnet ID does not have to be identified by contiguous bits in the host
ID portion of the internet address. The subnet ID can be identified by using
noncontiguous bits in the host ID portion of the internet address. It is strongly
recommended to use contiguous bits to identify the subnet ID.
Assume, for example, two networks where subnetting is used: subnetwork 9.4.70
and subnetwork 9.4.73.192. The first byte of the internet address is 9, which makes
it a class A network. 9.4.70 is an example of a network where two complete bytes
of the host ID have been used for the subnet ID. 9.4.73.192 is an example where
two complete bytes and part of a third byte of the host ID have been used for the
subnet ID. For 9.4.70, the range of host IDs available is 9.4.70.1 through
9.4.70.254. For 9.4.73.192, the range of host IDs available is 9.4.73.193 through
9.4.73.254.
A subnet mask is used to distinguish between a subnet ID and a host ID. Bits in the
subnet mask are set to 1 if the network treats the corresponding bit in the internet
address as part of the network ID and subnet ID and to 0 if it treats the bit as part
of the host ID. For example, a subnet mask of:
Subnet mask

11111111

00000000

specifies that the first three bytes identify the subnetwork and the fourth byte
identifies the host. Remember that the network portion of the internet address is
based on the class of internet address (A, B, C, D or E). The subnet mask must at
a minimum mask off the network portion of the address. In this case, because we
are discussing a class A address, the first byte must be all 1s. A subnet mask would
normally be specified in the same dotted decimal notation as an internet address.
Because the second and third bytes are being used to identify the subnet ID, those
two bytes should also be all 1s. Thus, in this example, the subnet mask is
255.255.255.0. If an internet address of 9.4.70.254 is compared against the subnet
mask:
Subnet mask
= 11111111 11111111 11111111 00000000
Internet address = 00001001 00000100 01000110 11111110
(logical and)
-------- -------- -------- -------Subnetwork
= 00001001 00000100 01000110 00000000

the subnetwork is 9.4.70 and the host ID is 254.
In the second example, the subnet mask for subnetwork 9.4.70 is 255.255.255.0.
The subnet mask for subnetwork 9.4.73.192 is 255.255.255.192. This is an example
of a subnetwork where part of a host ID byte has been used for the subnet ID. In
this case, the upper 2 bits of the fourth byte are used as part of the subnet ID. In bit
form, the subnet mask is:
Subnet mask

11111111

11000000

This means that the first 3 bytes and the first 2 bits of the fourth byte identify the
subnetwork, and the last 6 bits of the fourth byte identify the host. If an internet
address of 9.4.73.212 is compared against the above subnet mask:
Subnet mask
= 11111111 11111111 11111111 11000000
Internet address = 00001001 00000100 01001001 11010100
(logical and)
-------- -------- -------- -------Subnetwork
= 00001001 00000100 01001001 11000000

The subnetwork is 9.4.73.192 and the host ID is 20.
It is also possible to have a subnet mask where the network ID part is not
contiguous. For example:
Chapter 1. TCP/IP on AS/400

Subnet mask

11111111

01100000

01000000

This method is not normally used and is not recommended.
For AS/400 business computing systems in the above network, the full route table
could be:
Work with TCP/IP Routes
Type options, press Enter.
1=Add
2=Change
4=Remove

Opt
_
_
_

Route
Destination
______________
*DFTROUTE
9.4.70.0

System:

SYSNAM01

5=Display

Subnet
Mask
______________
*NONE
255.255.255.0

Next
Hop
______________
9.4.73.193
9.4.73.194

Preferred
Interface
*NONE
*NONE

F3=Exit
F5=Refresh
F6=Print list
F10=Work with IP over SNA routes
F11=Display type of service F12=Cancel
F17=Top
F18=Bottom

Bottom

Figure 6. AS/400 TCP/IP Subnet and Subnet Mask

The default is to route all traffic to the router associated with that subnetwork. No
routing configuration is required within the same subnetwork.
All hosts in the same subnetwork must use the same subnet mask.

Broadcast Addresses
Broadcast addresses are used to address multiple recipients on a network as
opposed to addressing a single recipient, which is done through unicast addresses.
Another type of IP address used for the purpose of sending a message to multiple
nodes on a network is the muliticast address. In the paragraphs that follow,
broadcast addresses are discussed. For more information about IP multicasting,
see “IP Multicasting” on page 91.
While there are several types of broadcast addresses, they can be separated into
two categories: the limited broadcast address and the directed broadcast address.
On each physical network, a limited broadcast address is an internet address that
consists of all 1 bits (255.255.255.255.). A directed broadcast address is an
internet address with a valid network ID and a host ID of all 1 bits. There are
different types of directed broadcast addresses, including network-directed,
subnet-directed, and all-subnets-directed.

OS/400 TCP/IP Configuration and Reference V4R4

Limited broadcasts only apply to the physical network. Packets addressed to the
limited broadcast address are not forwarded beyond the physical network of origin.

Domain Name System (DNS)
An Internet address is used to establish a connection between your system and
another system in a network. Because Internet addresses can sometimes be
difficult to remember, another naming convention is used. This naming convention is
called the Domain Name System (DNS). DNS names provide an easier way to
identify systems in a network.
When DNS is configured to run as part of TCP/IP, it is referred to as a DNS server.
For more information about AS/400 DNS server configuration and functions, see
“Chapter 18. AS/400 Domain Name System (DNS)” on page 421.

Domain and Host Name
A domain name identifies where your system is located within a hierarchy of
groups of systems. Domain names consist of labels that are separated by periods
(for example, ABC.DEF.XYZ). Within a domain represented by a domain name, there
can be many systems, and each must have a unique host name. A system’s host
name can be used by remote servers to associate an Internet address with the
system. Since host names are only unique within a domain, a host name is usually
combined with a domain name in the form host.domain, which is called a
fully-qualified host name.
Note: SMTP often refers to the host or host.domain combination as a domain. For
clarity, it is refered to in this publication as a SMTP domain.
When a network is small, the host names can be a sequence of characters without
any further structure. The advantage of this kind of name is that it is convenient and
easy to remember. The disadvantage is that it is not suitable for large sets of
machines for the following reasons:
v When the number of sites increases, the potential for conflicting names
increases.
v The authority for adding new names must rest at a single site, and the
administrative work load increases as the number of sites increase.
v The name-to-address bindings change frequently, and the cost of maintaining
correct copies at each site is high.
The answer to these problems is the decentralization of the naming process by
delegating authority for parts of the network. The name area of the network is
partitioned at the top level. The top level delegates authority (where it has some
authority) for the partitions. The top level need not be bothered by changes within
the different partitions.
The syntax of hierarchically assigned names reflects the hierarchical delegation of
authority used to assign them. For example, the names of the form local.site mean
that site is the top level of the hierarchy and this name has been authorized by the
central authority; local is a host name controlled by the site. The authority can be
further subdivided at each level. In this example, the site can be divided into two
groups:
v Production
Chapter 1. TCP/IP on AS/400

v Marketing
Syntactically, adding a new level introduces another subdivision to the name. In this
example, the machine can belong to the marketing group with the name:
local.market.site. Local is the host name, and market.site is the domain name.

Naming Conventions for Domain Names and Host Names
Normally the hierarchical machine names are assigned according to the structure of
organizations that obtain authority for parts of the namespace, not according to the
structure of the physical network interconnections.
A domain name or a host name can be a text string having 2 to 255 characters.
Domain names consist of one or more labels separated by periods. Each label can
contain up to 63 characters. The following characters are allowed in domain names:
v Alphabetical characters A through Z
v Digits 0 through 9
v Underline (_)
Note: The Underline character (_) is not fully supported by all implementations
outside of AS/400.
v Minus sign (-)
v Period (.). Periods are only allowed when they separate labels of domain style
name (refer to RFC 1034, Domain Names - Concepts and Facilities.).
Other naming conventions for domain names and host names include the following:
v Uppercase characters and lowercase characters are allowed, but no significance
is attached to the case.
v The first character of each part of the name separated by periods must be an
alphabetic character (uppercase A-Z or lowercase a-z).
v The last character of each part of the name separated by periods must be an
alphabetic character (uppercase A-Z or lowercase a-z) or a numeric character
(0-9).
v Blanks cannot be embedded.
v Only the special characters period (.), minus sign (-), and underline (_) are
allowed.
v Parts of the name separated by periods (.) cannot exceed 63 characters.
v Each part of the name must be at least 1 character.
v Fully-qualified host names including all periods cannot be more than 255
characters.
v Advanced program-to-program communications (APPC), over TCP/IP (part of
AnyNet/400) uses the host name to map location names to Internet addresses.
The host name must be in the form:
location.netid.SNA.IBM.COM

Where location is the remote location the program is opening to, and netid is the
network identifier for this connection. SNA.IBM.COM is the qualifier that
designates this as the APPC over TCP/IP domain.
Location names support characters that cannot be present in host names.
Therefore, the APPC application can open only to locations that fulfill the TCP/IP
host name syntax. This limits location names used for APPC over TCP/IP to the

OS/400 TCP/IP Configuration and Reference V4R4

characters A-Z (uppercase and lowercase), 0-9, $ (dollar), @ (at sign), and #
(number sign). The location name must begin with an alphabetic character.
v Try to limit your domain name labels to 12 characters because shorter labels are
easier to remember.
v It is a common practice to use hierarchical names that allow predictable
extensions for change and growth. Domain names normally reflect the delegation
of authority or hierarchy that is used to assign them.
For example, the name SYS1.MFG.ABC.COM can be broken down into the
following:
– COM: All commercial networks.
– ABC.COM: All systems in the ABC company’s commercial network.
– MFG.ABC.COM: All manufacturing systems in the ABC company’s commercial
network.
– SYS1.MFG.ABC.COM:
A host that is named SYS1 in the manufacturing area of the ABC company’s
commercial network.
The COM designation is one of several domain names that are used when
connecting to the Internet. Some of the other domain names are as follows:
ARTS Entities with activities related to culture and entertainment
COM

Commercial organizations

Country code
Countries that may be other than US
EDU

Educational institutions

FIRM

Business or firm

GOV

Government institutions

INFO

Entities that provide information services

MIL

Military groups

NET

Major network support centers (Internet)

NOM

An individual or personal nomenclature

ORG

Organizations

REC

Entities with activities related to recreation and entertainment

STORE
Businesses offering goods to purchase
WEB

Entities with activities related to the world wide web

For example, one of the domain names used in this book
(SYSNAM01.SALES.ABC.COM) indicates the following:
- The Internet authority has assigned company “ABC” into the commercial
organizations group.
- Company ABC authority has assigned this address to the group named
SALES.
- Company ABC authority has assigned SYSNAM01 as the name for this
IBM AS/400 business computing system.

Chapter 1. TCP/IP on AS/400

Routing
Routing is the process of mapping a path to send a packet to its destination
Internet address. Routing can be direct or indirect. Direct routing is used when the
source and destination nodes are on the same physical network. When direct
routing is used, the source node sends the packet on the network with the
destination hardware address in the link layer protocol header. The destination node
hardware detects its own address in the packet header and accepts the packet.
Indirect routing is used when the source and destination nodes are not on the same
physical network. The source node uses its routing tables to determine which router
will forward packets to the destination node. The packet is put on the network with
the router’s hardware address in the network header, and the destination’s Internet
address in the IP header. Thus, the router hardware receives the packet from the
network, and the router IP software determines the packet’s destination from the IP
header.

Introduction to TCP/IP Protocols on AS/400
Network protocols are sets of rules that control the communication and transfer of
data between two or more devices in a communications system. The term TCP/IP
refers to a family of nonproprietary network protocols, of which TCP, providing
host-to-host transmission, and IP, providing data routing from source to destination,
are two important parts.
The topics that follow discuss only those protocols that are available on the AS/400
business computing system.
TCP/IP consists of a layered structure of protocols that range from low-level,
hardware-dependent programs, to high-level applications. Each TCP/IP layer
provides services to the layer above it and uses the services provided by the layer
below it.
The layers are defined as follows:
Application
Provides a way for a process to cooperate with another process on the
same or a different host.
Transport
Provides communication from one application program to another. Such
communication is often called end-to-end data transfer.
Internetwork
Makes the entire physical network seem like a single virtual network. This is
achieved by shielding the higher levels from the underlying network
architecture.
Network Interface or Data Link
Provides the interface to the actual network hardware. Examples are
token-ring and Ethernet.
Hardware
This layer is not part of the TCP/IP family and is represented by dotted
lines. This layer consists of the hardware-specific network protocols.

OS/400 TCP/IP Configuration and Reference V4R4

Application Protocols
Application protocols are the highest-level protocols within the application layer. The
application layer overall consists of several independent protocols that put into
effect commonly used applications.
These protocols are able to communicate with applications on the same host or on
different hosts. They serve as the user-visible interface to the TCP/IP protocol suite
and use UDP and TCP protocols as methods for data transmission. Some of the
most frequently used application protocols include FTP, SMTP, and TELNET.

Application Protocol Standards
The TCP/IP protocols include standards for many common applications. A
discussion of each follows.

File Transfer Protocol (FTP)
FTP is an AS/400 TCP/IP application that enables you to transfer files between
local and remote hosts. It does this through the use of the FTP subcommands, GET
and PUT. FTP transfers files by using either an ASCII or EBCDIC mode. ASCII
mode transfers data sets that contain only text characters.

Remote Printing (Line Printer Requester and Line Printer
Daemon)
AS/400 TCP/IP provides client support and server support for remote printing. The
client, line printer requester (LPR), allows the user to send spooled files to a remote
system that is running a remote printer daemon (LPD) server.

Bootstrap Protocol (BOOTP)
BOOTP is a TCP/IP protocol that allows for booting systems remotely to the
network. BOOTP is used to support the IBM Network Station for AS/400.

Trivial File Transfer Protocol (TFTP)
Trivial File Transfer Protocol (TFTP) is a simple protocol and is used solely to
provide basic file transfers to and from a remote server. TFTP is used to support
the IBM Network Station for AS/400.

Route Daemon (RouteD) Server
The Route Daemon provides support for the Routing Information Protocol (RIP) on
AS/400. RIP is the most widely used routing protocol today. RIP is an Internet
Gateway Protocol used to assist TCP/IP in the routing of IP data packets.

Remote Execution (REXEC) Server
The Remote Execution server allows a client user to submit system commands to a
remote server system.

Simple Mail Transfer Protocol (SMTP)
AS/400 TCP/IP provides for the exchange of electronic mail between host servers
running TCP/IP by using SMTP. The SMTP application is based on end-to-end
delivery, which means that an SMTP client contacts the destination host’s SMTP
Chapter 1. TCP/IP on AS/400

server directly in an effort to deliver the mail. The SMTP client will actually retain
and retry transmission until the mail item is successfully delivered to the intended
destination or recipient.

Post Office Protocol (POP) Mail Server
The POP server is the AS/400 implementation of the Post Office Protocol (POP)
Version 3 mail interface. This server is a store-and-forward mail system that
provides electronic mailboxes on AS/400 from which clients can retrieve mail. POP
allows users to exchange multimedia mail.
The POP application allows AS/400 systems to act as POP servers for any clients
that support the POP mail interface, including clients running on Windows, OS/2,
AIX and Macintosh.

TELNET Protocol (TELNET)
AS/400 TCP/IP TELNET provides client and server support that allows remote
logon to hosts within an internet.

Simple Network Management Protocol (SNMP)
AS/400 TCP/IP SNMP provides a means for managing an internet environment.
SNMP allows network management by elements, such as routers and hosts.
Network elements act as servers and contain management agents that perform the
management functions requested. Network management stations act as clients;
they run the management applications that monitor and control the network. SNMP
provides a means of communicating between these elements and stations to send
and receive information about network resources.
AS/400 can be an agent in an SNMP network. That is, the AS/400 system gathers
information about the network and performs the management functions that are
requested by some remote SNMP manager. At this time, AS/400 cannot be an
SNMP manager in a TCP/IP network.
Simple Network Management Protocol (SNMP) is used predominately in TCP/IP
networks. However, OS/400 AnyNet support allows OS/400 SNMP support to be
used in a SNA network.
For additional information about SNMP, see the Simple Network Management
Protocol (SNMP) Support, SC41-5412-00 book.

5250/Hypertext Markup Language (HTML) Workstation Gateway
The 5250/Hypertext Markup Language (HTML) Workstation Gateway (WSG) server
is an application that automatically transforms AS/400 5250 applications to
Hypertext Markup Language (HTML). This allows users to run AS/400 applications
from any PC that has a WEB browser, and allows for TCP/IP network connectivity
to the AS/400 host.

Domain Name System Server (DNS)
The Domain Name System (DNS) server is used by applications to translate
domain names of hosts to IP addresses. The Domain Name System is the network
naming service of intranets and the Internet.

OS/400 TCP/IP Configuration and Reference V4R4

Dynamic Host Configuration Protocol (DHCP)
The Dynamic Host Configuration Protocol (DHCP) provides a framework for passing
configuration information to hosts on a TCP/IP network.
DHCP can function either as a DHCP server or a BOOTP/DHCP Relay Agent.
If DHCP functions as a DHCP server, it processes DHCP packets on the local
system. If DHCP functions as a BOOTP/DHCP Relay Agent, it then relays DHCP
and BOOTP packets on the local system, but does not process them.

Point-to-Point Protocol (PPP)
PPP is a method of transmitting datagrams over serial point-to-point links for wide
area network (WAN) connectivity.

OS/400 Network File System Support
OS/400 Network File System (NFS) Support is a replacement for the TCP/IP File
Server Support/400 (FSS/400) licensed program offering. Users who are
accustomed to working with FSS/400 will notice many similarities between FSS/400
and NFS. It is important to note, however, that FSS/400 and NFS are not
compatible with each other. At any given time, only one of these applications may
be executing.
NFS support allows the AS/400 system to function as a file server on the Internet. It
does this by making remote objects stored in a file system appear to be local, as if
they reside in the local host.
With NFS, all systems in a network can share a single set of files. This eliminates
the need for duplicate file copies on every network system. Using NFS aids in the
overall administration and management of users, systems, and data. For more
information about the Network File System see the book, OS/400 Network File
System Support, SC41-5714-01.

Application Program Interfaces (APIs)
Many times an enterprise has unique interoperability requirements for its private
networks. This means that the enterprise must provide its own applications to fulfill
these unique requirements. On AS/400, this is accomplished with several
application programming interfaces (APIs).
For helpful reference information about all of the OS/400 APIs, see the System API
Reference, SC41-5801-03.

Sockets Interface
A sockets interface (sockets) allows you to write your own applications to
supplement those that are supplied by TCP/IP. Sockets allow unrelated processes
to exchange data locally and over networks. Both connection-oriented and
connectionless communications are provided for TCP/IP. With this support you can
write applications to the TCP, UDP, and IP protocols directly. The TCP/IP
applications that run on sockets are FTP, SMTP, SNMP, LPR, LPD, BOOTP, TFTP,
RouteD, and REXEC. The sockets interface operates over TCP/IP or AnyNet/400.

Chapter 1. TCP/IP on AS/400

For additional information about sockets, see the Sockets Programming,
SC41-5422-03 book.

Send MIME Mail API
The Send MIME Mail API allows applications to use SMTP and TCP/IP to send mail
to the Internet.

Pascal API
The TCP/UDP programming interface was originally developed to provide system
programmers with a programming interface to the TCP or UDP protocols via a set
of procedure calls from an AS/400 Pascal program. This interface is no longer
documented in this publication because the AS/400 Pascal compiler is no longer
available. For information about the withdrawal of support for the Pascal compiler
see, New Release Planning for V3R7, SA41-4100.
The run-time support for the Pascal API is still included in the program product IBM
TCP/IP Connectivity Utilities for AS/400 (5769-TC1). Existing applications that use
the Pascal API can continue to be used. However, any new AS/400 TCP/IP
applications should use the sockets API.

Important Note:
Because of changes made to AS/400 TCP/IP in V3R1, pre-V3R1 TCP/IP
applications that use the Pascal API must be recompiled to function correctly
in V3R1 or later.

Multiprotocol Transport Networking Architecture
The Multiprotocol Transport Networking (MPTN) architecture implementation on
AS/400 allows Common Programming Interface Communications (CPI
Communications), intersystem communications function (ICF), and sockets to flow
over either TCP/IP, Systems Network Architecture (SNA), or Internetwork Packet
Exchange (IPX). On AS/400, the MPTN architecture is put into effect as AnyNet/400
support. For more information about AnyNet/400, see “AnyNet/400” on page 19.

Transport Protocol
This layer provides the end-to-end data transfer. This layer allows communication
between application programs. Example protocols that provide transport services
are Transmission Control Protocol (TCP) and User Datagram Protocol (UDP).

Transmission Control Protocol (TCP)
TCP is a widely used connection-oriented protocol that enables the transfer of data
from a source to a destination. TCP provides a reliable delivery of a stream of bytes
in sequence. TCP takes a stream of data, breaks it into segments (a TCP header
and application data), sends each one individually (using IP), and then reassembles
the segments back into the original stream. If any segments are lost or damaged
during the transmission, TCP detects this fact and resends the missing segments.
Most of the user application protocols, such as TELNET, FTP and SMTP, use TCP.

OS/400 TCP/IP Configuration and Reference V4R4

User Datagram Protocol (UDP)
UDP allows your application programs to send datagrams to other programs on
other systems with a minimum of protocol overhead. UDP does this through the use
of ports. Unlike TCP, UDP is datagram oriented and does not guarantee the
delivery of data in sequence. Datagrams may possibly be dropped or reordered as
they travel from the source to the destination. UDP can be used instead of TCP
when the application does not want to incur the overhead of TCP connecting and
disconnecting. It then becomes the responsibility of the application to ensure
reliable data transfer and sequencing of datagrams.
The following TCP/IP applications use UDP:
v SNMP
v TFTP
v DNS
AS/400 UDP also includes multicast support, beginning with Version 4 Release 2.

TCP and UDP Ports
A port is an integer value from 1 to 65535 that is used to identify a TCP/IP
application. TCP and UDP protocols use ports to identify a unique origin or
destination of communication with an application. There are two unique sets of
ports. One set is for TCP processing, and the other is for UDP processing. They are
completely independent sets of ports and have no relationship to one another.

Well-known Ports
Commonly used protocols and applications, such as FTP and SMTP, have assigned
port numbers. These assigned port numbers are called well-known ports. TCP and
UDP port numbers 1 to 1023 are reserved for the well-known ports and should not
be used by user application programs. If the user specifies one of these ports, it
can affect the operation of those applications. Refer to RFC 1700, entitled,
Assigned Numbers, for a list of well-known ports.
To see the list of ports currently defined on AS/400, perform the following steps:
1. Use the Configure TCP/IP (CFGTCP) command to get to the Configure TCP/IP
menu
2. Select option 21 (Configure related tables)
3. Select option 1 (Work with service table entries)

Point-to-Point TCP/IP
Dial-up TCP/IP, known as point-to-point TCP/IP, is used to dial into remote systems,
or allow remote systems to dial into AS/400 over a telephone line using a modem.
Null modem or non-switched connections are also supported. The Serial Line
Internet Protocol (SLIP) and the Point-to-Point Protocol (PPP) are supported on
AS/400.

Chapter 1. TCP/IP on AS/400

Internetwork Protocol
This layer provides the virtual network image of the physical network. This layer
shields the higher levels from the typical network architecture below it. Internet
Protocol (IP) is the most important protocol at this level. IP is a connectionless
protocol that does not provide reliability, flow control, or error recovery, and does not
assume reliability from the lower layers. An example of a protocol at this level is the
Internet Control Message Protocol (ICMP).

Internet Protocol
The Internet Protocol (IP) provides the basic transportation rules for communication
between hosts on the different networks that make up an internet. A host is a node
on the network that has a unique internet address and an associated system name.
IP is responsible for routing packets from a host on one network through a series of
routers to a host on the same or another network.
In IP-based networks, information is transmitted between nodes in the form of
packets. A packet includes an IP header and data. A packet or network frame can
contain a complete IP datagram or a fragment of an IP datagram. A datagram is
the basic unit of information in the TCP/IP protocol, consisting of a source address,
destination address, and data. At the internet level, all addressing is host-to-host,
using fixed-length addresses to identify source and destination hosts. The protocol
layers above only need to know each host’s internet address to make a connection.
See Figure 7 and Figure 8 for illustrations of the terms packet, datagram, and
segment.
If there is a transmission on the network:

Figure 7. Packet and Frame Terminology

Before the IP is broken into pieces or after IP reassembly:

Figure 8. Segment and Datagram Terminology

After packets are received, they are passed to the IP layer. Datagrams are
reassembled if necessary, and stripped of the header before being passed on to the
next higher protocol layer. IP does not acknowledge receiving a datagram, nor is it
responsible for retransmitting or providing flow and error control. Reliable delivery

OS/400 TCP/IP Configuration and Reference V4R4

must be ensured by a higher level protocol, such as TCP. Integral to every IP
implementation is the Internet Control Message Protocol (ICMP), which is used for
reporting errors, congestion reporting, and first-hop router redirection.

Internet Control Message Protocol
The Internet Control Message Protocol (ICMP) provides for error and control
messages between host systems (peer computers in a network) and routers.
Routers and host systems use ICMP to send reports of problems. ICMP also
includes an echo request or reply message that is used to test whether a
destination can be reached and is responding. This is commonly known as PING
(Packet InterNet Groper).

Internet Group Management Protocol
The Internet Group Management Protocol (IGMP) is used by IP hosts to report their
host group memberships to neighboring multicast routers. Multicast routers send
Host Membership Query messages to discover which host groups have members
on their attached networks. Hosts respond to a Query by generating Host
Membership Reports, reporting each host group to which they belong. The multicast
routers use this information to determine where multicast datagrams need to be
forwarded.

Address Resolution Protocol
The Address Resolution Protocol (ARP) dynamically associates internet addresses
to physical hardware addresses on a local network. ARP relies on the broadcast
capabilities of the underlying media to provide this function.

AnyNet/400
AnyNet/400 is part of the AnyNet family of products. AnyNet products allow
application programs written for one communications protocol to run over non-native
protocols without changing (or recompiling) the application programs. The
destination address determines if the request is sent over the native protocol or
through the AnyNet code and on to a non-native protocol.
AnyNet/400 allows sockets, intersystem communications function (ICF), CPI
Communications (CPI-C), and CICS/400 applications to run over APPC, TCP/IP,
and Internetwork Packet eXchange (IPX). AnyNet/400 is based on the Multiprotocol
Transport Network (MPTN) architecture, and is designed to allow any application to
run over any networking protocol. You can use AnyNet/400 to:
v Access APPC using TCP/IP if your applications were developed for system
network architecture (SNA) but you are using TCP/IP to connect the systems
v Access APPC using IPX if your applications were developed for SNA but you are
using IPX to connect the systems
v Access sockets using SNA if your sockets applications were developed for
TCP/IP but you are using SNA to connect the systems
v Access sockets using IPX if your sockets applications were developed for TCP/IP
but you are using IPX to connect the systems.
AnyNet/400 is shipped with the AS/400 base operating system, OS/400.

Chapter 1. TCP/IP on AS/400

Accessing APPC Using TCP/IP (SNA Over IP)
AnyNet/400 APPC over TCP/IP allows you to extend intersystem communications
function (ICF), common programming interface for communications (CPI-C), and
CICS/400 applications to TCP/IP users without adding a separate APPC network.
You can also allow any OS/400, ICF, CICS/400 or CPI-C application (such as
DRDA) to communicate across a TCP/IP network.
The Communications Configuration, SC41-5401-00 book, tells you how to configure
AnyNet/400 APPC over TCP/IP.

Accessing APPC Using IPX (SNA Over IPX)
AnyNet/400 APPC over IPX allows you to extend ICF, CPI-C or CICS/400
applications to IPX users without adding a separate APPC network. You can also
allow any OS/400, ICF, CICS/400 or CPI-C application (such as DRDA) to
communicate across an IPX network.

Accessing Sockets Using IPX (IP Over IPX)
AnyNet/400 Sockets over IPX allows you to add Berkeley Software Distribution
(BSD) Sockets applications to existing IPX networks, without adding a separate
TCP/IP network. This allows OS/400 users to use most Sockets applications (such
as FTP, SMTP and SNMP) across an IPX network.
The book Internetwork Packet Exchange (IPX) Support, SC41-5400-00, tells you
how to configure and use the Novell protocol suite with OS/400.

Accessing Sockets Using SNA (IP over SNA)
AnyNet/400 Sockets over SNA allows you to add BSD Sockets applications to
existing SNA networks without adding a separate TCP/IP network. This allows
OS/400 users to use most sockets applications (such as FTP, SMTP and SNMP)
across an SNA network.
The book Sockets Programming, SC41-5422-03, describes how to use both AnyNet
and non-AnyNet sockets.

OS/400 TCP/IP Configuration and Reference V4R4

Chapter 2. Configuring TCP/IP
This chapter explains how to configure an AS/400 business computing system for
Transmission Control Protocol/Internet Protocol (TCP/IP). If this is the first time that
you have configured TCP/IP on an AS/400 system, you should read the entire
chapter before performing any of the configuration tasks.
If you are unfamiliar with TCP/IP, consider reading Chapter 1. TCP/IP on AS/400.
For a complete formal description of TCP/IP, you can read the Request for
Comments (RFC). Or, refer to any of the TCP/IP references that are listed in
“Request For Comments (RFC)” on page 602. Information about how to order an
RFC is also listed within that topic.

What you need to know before you can configure TCP/IP
Before you start configuring TCP/IP, you must ensure that the TCP/IP Connectivity
Utilities for AS/400 licensed program (LP) is installed on your system. See
“Installing the TCP/IP Application Programs” on page 23 for more information.
The AS/400 has many commands and menus available to help you configure
TCP/IP on AS/400. Before you begin this task, take time to review the TCP/IP
Administration (TCPADM) menu, Figure 9 on page 26, and the Configure TCP/IP
(CGFTCP) menu, Figure 10 on page 28.
The initial displays and menus that are shown when you configure TCP/IP on your
system may not contain any entries. The sample command line interface displays in
this chapter may already contain data, which was entered for the purpose of
example in previous configuration steps.
Performing configuration tasks on a single network or even a simple multiple
network requires that you do some planning before configuring TCP/IP on any
system in that network, including an AS/400. To help you get started with setting up
TCP/IP, this chapter includes complete planning details and checklists.
Once you have designed a plan, follow the step-by-step process that is outlined for
you in this chapter. Each step guides you through TCP/IP installation and
configuration on your system, defines various terms, and describes how these
terms relate to TCP/IP.
Using the Operations Navigator interface: You can configure TCP/IP through the
Operations Navigator interface wizard. Information related to Operations Navigator
is located in the online help. See the online help in Operations Navigator for
information about the following TCP/IP functions:
v Configuring TCP/IP, including basic functions such as starting and stopping
TCP/IP
v Creating a new Ethernet line
v Creating a new token-ring line
v Working with TCP/IP interfaces, including configuring a TCP/IP route
v Working with TCP/IP host tables, including configuring a TCP/IP host name and
domain name
v Verifying a TCP/IP connection (PING)
© Copyright IBM Corp. 1997, 1999

Planning for TCP/IP Installation and Configuration
If you are in charge of configuring an AS/400 system for TCP/IP communications
you will, in most cases, include your AS/400 system in an existing TCP/IP network.
Before you are able to start configuring, you will need to collect all of the required
information.
Start by contacting the person responsible for the TCP/IP network of your company,
your TCP/IP network administrator. When talking to the administrator, you may want
to use Table 3 on page 51 and Table 4 on page 51 as checklists to record the
necessary information.

Gathering Information About your Network
After collecting the preliminary information about your network, plan the installation
and configuration of TCP/IP by using the steps that are listed below:
1. Draw a diagram of your network: A diagram similar to that shown in Figure 32
on page 53 will help you decide how you want to attach your AS/400 system to
the other systems in the network. Include other data that relates to your
network, such as:
v Line description information
v Internet Protocol addresses and domain names
v The number of route entries that are required
Refer to Table 3 on page 51.
2. Identify the names of the systems in your network: For example, do either
of the following:
v Build a local host table.
v Identify a Domain Name System (DNS) server for maintaining host table
entries.
3. Install the appropriate hardware and software: You must install the
appropriate hardware adapters in your AS/400 system if you are going to
connect to the following networks:
v X.25 packet-switching
v Frame relay
v Token-ring
v Ethernet
v
v
v
v
v

Fiber distributed data interface (FDDI)
Shielded twisted pair distributed data interface (SDDI)
Wireless local area network (LAN)
Synchronous or asynchronous communications line
Twinaxial data link support (TDLC)

You also need to make sure that the appropriate software is installed on all the
systems. On the AS/400 system, the OS/400 licensed program and the TCP/IP
Connectivity Utilities for AS/400 licensed program must be installed.
4. Assign names and Internet addresses: If you are attaching to an existing
network, you need to know the Internet addresses and names used by the other
systems. An existing network usually has an administrator who keeps such

OS/400 TCP/IP Configuration and Reference V4R4

information. If this person is someone other than you, have that individual
provide you with the Internet address to use for your system.
Depending on the size of your network and its complexities, determine whether
a host table or a DNS server is the preferred method for maintaining and
updating host name and IP address associations. In this chapter, refer to “Step
6—Configuring TCP/IP Host Table Entries” on page 38. For information about
configuring and using a DNS server, see page 421.
5. Obtain X.25 network addresses: If you plan to use TCP/IP on an X.25 private
or public data network, you need to know whether you will be using a switched
virtual circuit (SVC) or permanent virtual circuit (PVC).
v To use an SVC, you need to know the network address of each remote
system in the network with which you want to communicate.
v To use a PVC, you need to know the related logical channel identifier. You
can have a network address or a permanent virtual circuit, but not both, for a
remote system information entry.
If a remote system is an AS/400 system, you can determine its network
address by using the Display Line Description (DSPLIND) command on that
remote system.
6. Familiarize yourself with the TCP/IP Administration Menu: The TCP/IP
Administration menu (Figure 9 on page 26) provides easy access to common
functions associated with administering TCP/IP.
To get to this menu, enter the GO TCPADM command from the AS/400 Main
Menu.
7. Familiarize yourself with the Configure TCP/IP Menu: The Configure TCP/IP
menu (Figure 10 on page 28) guides you through all the tasks for configuring
your AS/400 system to communicate with other systems in a TCP/IP network.
You can reach this menu in two ways:
v Select option 1 on the TCPADM menu.
v Enter the Configure TCP/IP (CFGTCP) command.
Once you have documented configuration information, you are ready to install the
TCP/IP program on your AS/400 system. The information in the section that follows
will help you do that. See “Installing the TCP/IP Application Programs”.
For information about TCP/IP addressing and connecting to the Internet, see
“TCP/IP Addressing” on page 24. This topic discusses the methods for assigning
addresses within your own network and offers an example.

Installing the TCP/IP Application Programs
Important
To determine whether the TCP/IP LP is already installed, enter GO LICPGM
(Go Licensed Program) on the command line and then select Option 10 to
display the installed licensed programs. If the TCP/IP Connectivity Utilities LP
is not installed on your system, continue by following the instructions in this
section to perform the installation.

Installing TCP/IP on your AS/400 allows you to connect an AS/400 to a network.

Chapter 2. Configuring TCP/IP

Perform the following steps to install TCP/IP on your AS/400 system:
1. Insert your installation media for TCP/IP into your AS/400. If your installation
media is a CD-ROM, insert it into your optical device. If your installation media
is a tape, insert it into your tape drive.
2. Type GO LICPGM at the command prompt and press Enter to access the Work
with Licensed Programs display.
3. Select option 11 (Install licensed programs) on the Work with Licensed
Programs display to see a list of licensed programs and optional parts of
licensed programs.
4. Type 1 in the option column next to 5769TC1 TCP/IP Connectivity Utilities for
AS/400 licensed program. The Confirm Licensed Programs to Install display
shows the licensed program you selected to install. Press Enter to confirm.
5. Fill in the following choices on the Install Options display:
v Installation Device
Type OPT01, if installing from a CD drive.
Type TAP01, if installing from a tape drive.
v Objects to Install
The Objects to Install option allows you to install both programs and
language objects, only programs, or only language objects.
v Automatic IPL
The Automatic IPL option determines whether the system automatically starts
when the installation process has completed successfully.
When TCP/IP successfully installs, either the Work with Licensed Programs
menu or the Sign On display appears.
Note: For more detailed information about installing software, including
objects to install and the automatic IPL option, refer to the Software
Installation, SC41-5120-03 book.
6. Select option 50 (Display log for messages) to verify that you have installed the
licensed program successfully. If an error occurs, you will see the message Work
with licensed program function not complete on the bottom of the Work with
Licensed Programs display.
To use TCP/IP, you must configure it after you have completed the installation. See
“Configuring TCP/IP using the Command Line Interface” on page 29.

TCP/IP Addressing
TCP/IP addressing uses a unique Internet Protocol (IP) address for a specific node
in a TCP/IP network. Each node on a network is known as a host and has a unique
address.
You can assign your own addresses within your own network. To connect to the
Internet, the InterNIC assigns your network addresses and domain names. For
more information about how to contact the InterNIC registration services, see
Table 1 on page 4.
TCP/IP addressing is comprised of two parts: The TCP/IP address itself and the
subnet mask. The TCP/IP address is a 32-bit integer that contains both a network
portion and a host portion. This address is usually expressed in the decimal form

OS/400 TCP/IP Configuration and Reference V4R4

xxx.xxx.xxx.xxx, where xxx is an integer between 0 and 255. The subnet mask is a
bit mask that determines which bits in the TCP/IP address designate the network
versus the host part of the address.
IP protocol works closely with the network and host portions of the address as well
as the subnet mask.
TCP/IP addressing reflects your licensing and networking needs. The size of your
network is the starting point for determining your TCP/IP addressing.
The following TCP/IP example is based on six existing networks you might have in
your company:
v Network 1 needs 100 IP addresses.
v Network 2 needs 90 IP addresses.
v
v
v
v

Network
Network
Network
Network

3
4
5
6

needs
needs
needs
needs

40
50
50
50

IP
IP
IP
IP

addresses.
addresses.
addresses.
addresses.

For this example, if you are going to use class C addressing, you need to have two
class C addresses. You could use Networks 1 and 2 for one class C address and
Networks 3, 4, 5, and 6 for the other class C address. This arrangement allows for
future expansion of the networks.
Continuing with this example, assume that the class C addresses are 192.1.1.x and
192.1.2.x. Here is how TCP/IP addressing could work in this example:
Network 1:
Network: 192.1.1.0
Subnet mask: 255.255.255.128
Usable range of IP addresses for hosts: 192.1.1.1 through
192.1.1.126.
Network 2:
Network: 192.1.1.128
Subnet mask: 255.255.255.128
Usable range of IP addresses for hosts: 192.1.1.129 through
192.1.1.254.
Network 3:
Network: 192.1.2.0
Subnet mask: 255.255.255.192
Usable range of IP addresses for hosts: 192.1.2.1 through
192.1.2.62.
Network 4:
Network: 192.1.2.64
Subnet mask: 255.255.255.192
Usable range of IP addresses for hosts: 192.1.2.65 through
192.1.2.126.
Network 5:
Network: 192.1.2.128
Subnet mask: 255.255.255.192
Usable range of IP addresses for hosts: 192.1.2.129 through
192.1.2.190.
Network 6:

Chapter 2. Configuring TCP/IP

Network: 192.1.2.192
Subnet mask: 255.255.255.192
Usable range of IP addresses for hosts: 192.1.2.193 through
192.1.2.254.

The domain name for the entire network could be xyz.com. Lower-level domain
names could be group1.xyz.com for Networks 1 and 2 and group2.xyz.com for
Networks 3, 4, 5, and 6. In this example, only the local routers know that the
networks are actually different, physical networks.
Note: If you need further assistance with planning for TCP/IP addressing, refer to
RFC 1219, On the Assignment of Subnet Numbers.

Using the TCP/IP Administration Menu
The TCP/IP Administration menu (Figure 9) is a starting point for the configuration
tasks. To display the menu, enter GO TCPADM from the AS/400 Main Menu.
TCPADM

TCP/IP Administration

Select one of the following:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.

System:

Configure TCP/IP
Configure TCP/IP applications
Start TCP/IP
End TCP/IP
Start TCP/IP servers
End TCP/IP servers
Work with TCP/IP network status
Verify TCP/IP connection
Start TCP/IP FTP session
Start TCP/IP TELNET session
Send TCP/IP spooled file

20. Work with TCP/IP jobs in QSYSWRK subsystem
Selection or command
===>
F3=Exit

F4=Prompt

F9=Retrieve

F12=Cancel

Figure 9. TCP/IP Administration Menu

Following are descriptions of the menu options.
v Option 1. Configure TCP/IP: Displays the Configure TCP/IP menu. Use the
options on this menu to configure your local AS/400 system to communicate with
other systems in a TCP/IP network.
v Option 2. Configure TCP/IP applications: Displays the Configure TCP/IP
Applications menu. Use the options on this menu to configure the TCP/IP
licensed program (5769-TC1) applications installed on your system.
v Option 3. Start TCP/IP: Select this option to issue the Start TCP/IP (STRTCP)
command. This command initializes and activates TCP/IP processing, starts the
TCP/IP interfaces, and starts the TCP/IP server jobs.
v Option 4. End TCP/IP: Select this option to issue the End TCP/IP (ENDTCP)
command. This command is used to end all TCP/IP processing on this system.

OS/400 TCP/IP Configuration and Reference V4R4

v Option 5. Start TCP/IP servers: Select this option to issue the Start TCP/IP
Server (STRTCPSVR) command. This command is used to start the TCP/IP
application servers that are shipped with OS/400 or the TCP/IP licensed program
(5769-TC1). This command starts the TCP/IP application server jobs in the
QSYSWRK subsystem.
v Option 6. End TCP/IP servers: Select this option to issue the End TCP/IP
Server (ENDTCPSVR) command. This command is used to end the TCP/IP
application servers that are shipped with OS/400 or the TCP/IP licensed program
(5769-TC1). This command ends the TCP/IP application server jobs in the
QSYSWRK subsystem.
v Option 7. Work with TCP/IP network status: Select this option to issue the
Work with TCP/IP Network Status (WRKTCPSTS) command. This command is
used to view and manage the status information of your TCP/IP and IP over
Systems Network Architecture (SNA) interfaces, routes, and connections. This
command is the AS/400 version of the TCP/IP NETSTAT (Network Status)
command. NETSTAT is also shipped as an AS/400 command.
v Option 8. Verify TCP/IP connection: Select this option to issue the Verify
TCP/IP Connection (VFYTCPCNN) command. This command tests the TCP/IP
connection between your system and a remote system. The VFYTCPCNN
command is the AS/400 version of the TCP/IP PING (Packet InterNet Groper)
command. PING is also shipped as an AS/400 command.
v Option 9. Start TCP/IP FTP session: Select this option to issue the Start
TCP/IP FTP (STRTCPFTP) command. This command is used to start a file
transfer using TCP/IP. This command is the AS/400 version of the TCP/IP FTP
(File Transfer Protocol) command. FTP is also shipped as an AS/400 command.
v Option 10. Start TCP/IP TELNET session: Select this option to issue the Start
TCP/IP TELNET (STRTCPTELN) command. This command is used to start a
TELNET client session with a remote system. This command is the AS/400
version of the TCP/IP TELNET command. TELNET is also shipped as an AS/400
command.
v Option 11. Send TCP/IP spooled file: Select this option to issue the Send
TCP/IP Spooled File (SNDTCPSPLF) command. This command sends a spooled
file to be printed on a remote system. The remote system must be running
TCP/IP. The SNDTCPSPLF command is the AS/400 version of the TCP/IP LPR
(line printer requester) command. LPR is also shipped as an AS/400 command.
v Option 20. Work with TCP/IP jobs in QSYSWRK subsystem: Select this
option to work with the status and performance information for the active TCP/IP
jobs in the QSYSWRK subsystem. This option issues the Work with Active Jobs
(WRKACTJOB) command with these parameters:
WRKACTJOB SBS(QSYSWRK) JOB(QT*)

Using the Configure TCP/IP Menu
The Configure TCP/IP menu is shown here (Figure 10 on page 28) so that you are
familiar with all of the options available during configuration of the TCP/IP network.
To get to this menu, select option 1 on the TCPADM menu or enter the Configure
TCP/IP (CFGTCP) command.

Chapter 2. Configuring TCP/IP

CFGTCP

Configure TCP/IP

Select one of the following:
1.
2.
3.
4.
5.

System:

SYSNAM890

Work with TCP/IP interfaces
Work with TCP/IP routes
Change TCP/IP attributes
Work with TCP/IP port restrictions
Work with TCP/IP remote system information

10. Work with TCP/IP host table entries
11. Merge TCP/IP host table
12. Change TCP/IP domain information
20. Configure TCP/IP applications
21. Configure related tables
22. Configure point-to-point TCP/IP
Selection or command
===>
F3=Exit

F4=Prompt

F9=Retrieve

F12=Cancel

Figure 10. Configure TCP/IP Menu

Following are descriptions of the Configure TCP/IP menu options.
v Option 1. Work with TCP/IP interfaces: Select this option to add TCP/IP
interface information to the list of current interfaces or to display, change, print, or
remove TCP/IP interface information that you have already added. Select this
option to start or end a TCP/IP interface.
v Option 2. Work with TCP/IP routes: Select this option to add route information
or to display, change, print, or remove route information that you have already
added.
v Option 3. Change TCP/IP attributes: Select this option to run the Change
TCP/IP Attributes (CHGTCPA) command.
With this option you can change User Datagram Protocol (UDP) checksum
processing, IP datagram forwarding, IP time-to-live values, and other attributes
that relate to the TCP/IP protocol stack.
v Option 4. Work with TCP/IP port restrictions: Select this option to add port
restrictions or to display, remove, or print port restrictions that you have already
added.
v Option 5. Work with TCP/IP remote system information: Select this option to
add or remove X.25 data network addresses or to print the list.
v Option 10. Work with TCP/IP host table entries: Select this option to add host
IP addresses and their associated host names to the host table or to display,
change, print, rename, or remove items that you have already added.
v Option 11. Merge TCP/IP host table: Select this option to merge or replace a
local host table by using the Merge TCP/IP Host Table (MRGTCPHT) command.
v Option 12. Change TCP/IP domain information: Select this option to change
TCP/IP domain information.
Note: Prior to Version 4 Release 2, the Configure TCP/IP menu contained both
an option 12 and an option 13. In Version 4 Release 2, the functions of
options 12 and 13 were combined, and option 13 (Change Remote name

OS/400 TCP/IP Configuration and Reference V4R4

server) was removed from the menu. Option 12, formerly Change local
domain and host names, was renamed to Change TCP/IP domain
information.
v Option 20. Configure TCP/IP applications: Select this option to configure the
TCP/IP applications that are installed on your system. The list of applications
varies depending on whether the TCP/IP licensed program is installed on your
system. If the TCP/IP licensed program is not installed on your system, you can
configure only the following server applications:
– Simple Network Management Protocol (SNMP)
– Bootstrap Protocol (BOOTP) server
– Trivial File Transfer Protocol (TFTP) server
– Route Daemon (RouteD)
If the TCP/IP licensed program is installed on your system, you can configure the
following server applications:
– Simple Mail Transfer Protocol (SMTP)
– File Transfer Protocol (FTP), TELNET
– Post Office Protocol (POP) Version 3 mail server
– Line Printer Daemon (LPD)
– Remote Execution (REXEC) server
– Workstation gateway applications
– Simple Network Management Protocol (SNMP)
For information about configuring SNMP, see the Simple Network Management
Protocol (SNMP) Support book.
v Option 21. Configure related tables: Select this option to configure the tables
related to TCP/IP. These tables are:
– Protocol table
Contains a list of protocols used in the Internet.
– Services table
Contains a list of services and the specific port and protocol a service uses.
– Network table
Contains a list of networks and the corresponding IP addresses for that
network.
v Option 22. Configure point-to-point TCP/IP: Select this option to define,
change, or display your TCP/IP point-to-point (SLIP) configuration.

Configuring TCP/IP using the Command Line Interface
The following steps using the command line interface will guide you through
configuring TCP/IP on your AS/400 system:
1. Configuring line descriptions
2. Configuring TCP/IP interfaces
3. Configuring TCP/IP routes
4. Configuring TCP/IP attributes
5. Configuring remote system information (X.25)
6. Configuring host table entries

Chapter 2. Configuring TCP/IP

Note: For information about using a DNS server to manage entries, in place
of host tables, refer to 421.
7. Configuring local domain and host name
8. Starting TCP/IP
9. Verifying TCP/IP connection
10. Saving the TCP/IP configuration

Important Note:
To perform the configuration steps discussed throughout this chapter, you
need the special authority of *IOSYSCFG defined in your user profile.

Step 1—Configuring a Line Description
AS/400 TCP/IP supports various local area network (LAN) and wide area network
(WAN) connection types: Ethernet, token-ring, SDDI and FDDI, wireless LAN, X.25
SVC, and permanent virtual circuit (PVC), Async (for SLIP), Point-to-Point (PPP)
and frame relay. Refer to Appendix A. Configuring a Physical Line for TCP/IP
Communication for information about how to configure an Ethernet line for TCP/IP
communications.
These are the important parameters for configuring a line description:
v Line description name
v Resource name
v Local adapter address
v Ethernet standard
v Source service access point (SSAP) list.
The SSAP X'AA' required for an IEEE 802.3 Ethernet is automatically allocated if
you use the *SYSGEN special value.
When TCP/IP starts an interface, the line, controller, and device descriptions are
varied on automatically. If the controller and device descriptions for a line do not
exist, TCP/IP creates them automatically when it attempts to start an interface using
that line. This happens at TCP/IP startup time if the TCP/IP interface that is
associated with the newly configured line is set to AUTOSTART *YES.

Step 2—Configuring a TCP/IP Interface
In an AS/400 system, each line that connects to a TCP/IP network must be
assigned to at least one Internet address. You do this by configuring, or adding a
TCP/IP interface. The additional interfaces are logical interfaces, not physical ones.
These logical interfaces are associated with a line description.
An interface identifies a direct connection to a network using TCP/IP and a physical
medium (communications line). You must consider the following when defining an
interface:
Internet address
A 32-bit address assigned to hosts using TCP/IP. It is associated with the
line description.

OS/400 TCP/IP Configuration and Reference V4R4

Subnet mask
Defines which part of an Internet address forms the subnet (subnetwork)
field of an Internet address. An example of a single-network subnet mask is:
255.255.255.128.
Line description
Contains information describing a communications line that is attached to
the AS/400 system, as defined previously in “Step 1—Configuring a Line
Description” on page 30.
To find the names of the currently defined line descriptions, use the Work
with Line Descriptions (WRKLIND) command.
Associated local interface
Allows the network to which this interface is attached appear to be part of
the same network that the associated local interface is attached to. This is
referred to as transparent subnetting.
Transparent subnetting allows TCP/IP traffic to flow between the two
physical networks without defining additional routing. This is only valid for
broadcast-capable networks. This also requires the Internet address for Add
TCP/IP Interface (ADDTCPIFC) to be configured in the same network as
the associated local interface. An additional requirement is for the subnet
mask that is defined for the associated local interface.
Automatic start
Refers to whether the TCP/IP interface is started automatically whenever
TCP/IP is started. The default setting is *YES. If you choose *NO, you must
start the interface yourself by using the STRTCPIFC command or by
selecting option 9 (Start) on the Work with TCP/IP Interfaces display, as
shown in Figure 12 on page 32.
To add a TCP/IP interface, do the following:
1. Enter GO TCPADM to get the TCP/IP Administration menu.
2. Select option 1 to get to the Configure TCP/IP menu.
3. Select option 1 on the Configure TCP/IP menu.
The Work with TCP/IP Interfaces display is shown in Figure 12 on
page 32.
4. Type option 1 (Add) at the input-capable top list entry on this display to
go to the Add TCP/IP Interfaces (ADDTCPIFC) display, as shown in
Figure 11 on page 32.
(You can go directly to this display by typing ADDTCPIFC command on
any command line and pressing F4.)
AS/400 TCP/IP supports multihoming, which allows you to specify multiple
interfaces for each line description. For example, multihoming can be used to
assign multiple Internet addresses to a single physical line description. See
“Multihoming Function” on page 79 for further information.

Chapter 2. Configuring TCP/IP

Add TCP/IP Interface (ADDTCPIFC)
Type choices, press Enter.
Internet address . . . . . . . .
Line description . . . . . . . .
Subnet mask . . . . . . . . . .
Associated local interface . . .
Type of service . . . . . . . .
Maximum transmission unit . . .
Autostart . . . . . . . . . . .
PVC logical channel identifier
+ for more values
X.25 idle circuit timeout . . .
X.25 maximum virtual circuits .
X.25 DDN interface . . . . . . .
TRLAN bit sequencing . . . . . .

F3=Exit
F4=Prompt
F24=More key

F5=Refresh

Name, *LOOPBACK, *VIRTUALIP
*NONE
*NORMAL
*LIND
*YES

*MINDELAY, *MAXTHRPUT...
576-16388, *LIND
*YES, *NO
001-FFF

60
64
*NO
*MSB

1-600
0-64
*YES, *NO
*MSB, *LSB

F12=Cancel

Bottom
F13=How to use this display

Figure 11. Add TCP/IP Interfaces Display

When you are finished adding entries, the Work with TCP/IP Interfaces display
looks like Figure 12.
Work with TCP/IP Interfaces
Type options, press Enter.
1=Add
2=Change 4=Remove
Opt
-

5=Display

9=Start

System:

SYSNAM890

10=End

Internet
Address

Subnet
Mask

Line
Description

Line
Type

9.4.73.129

255.255.255.128

ETHLINE

*ELAN

Figure 12. Work with TCP/IP Interfaces Display

Note: Any change to the TCP/IP interfaces configuration, except for the automatic
start parameter, takes effect immediately.

Step 3—Configuring TCP/IP Routes
Do you need to add routes at all?
If you have several individual networks to which the AS/400 is not directly
attached, you must add routing entries to allow the AS/400 to reach these
remote networks.
If your AS/400 is attached to a single network, if there are no IP routers in
your network, you do not need to add routes.

To reach remote networks, at least one routing entry is required. If no routing
entries are manually added, your AS/400 cannot reach systems that are not on the

OS/400 TCP/IP Configuration and Reference V4R4

same network that the AS/400 is attached to. You must also add routing entries to
allow TCP/IP clients that are attempting to reach your AS/400 system from a remote
network to function correctly.
For example, suppose that someone using a PC is using the TELNET application to
start a remote terminal session on your AS/400 system. The application on the PC
must know the route or path to reach the AS/400 system. Your AS/400 system must
also be able to determine the route back to the PC. If the PC and your AS/400
system are not on the same network, a routing entry must exist on the PC and on
AS/400.
Note: You should plan to have the routing table defined so that there is always an
entry for at least one default route (*DFTROUTE). If there is no match on
any other entry in the routing table, data is sent to the IP router specified by
the first available default route entry. The only exception to this is if you
intend to dial out over a SLIP link to an Internet Service Provider or another
remote host. See “Using SLIP with an Asynchronous Line Description” on
page 126 for details.
Before adding routing entries, familiarize yourself with the following terms:
Route destination
The network ID portion of an Internet address. The network ID portion is
composed of the first byte, the first two bytes, or the first three bytes of the
Internet address (depending on the network class). The remaining bytes
define the host ID portion of the Internet address.
If subnetting is used, route destination includes the subnet part as well. In
other words, the route destination equals the address of a TCP/IP
network to be reached.
Subnet mask
A bit mask that defines which part of an Internet address forms the network
and the subnetwork.
The technique known as subnet addressing, subnet routing, or
subnetting allows a single network ID to be used on multiple physical
networks. This technique lets you define separate routes to different sets of
Internet addresses within a specific network.
For more information about subnet masks and subnetworks, refer to
“Subnetworks and Subnet Masks” on page 6.
Next hop
The Internet address of the first system in the route between your system
and the destination network. The next hop value is always an Internet
address. Next hops need to be hosts on a directly connected TCP/IP
network defined by the TCP/IP interfaces.
Maximum Transmission Unit (MTU) size
The maximum size (in bytes) of IP datagrams sent on a route. If you specify
*IFC, the size is calculated for you based on values found in the AS/400
line description. The maximum size specified for a particular route must not
be larger than the smallest MTU supported by any router or bridge in that
route. If you specify a larger size, some datagrams may be lost.
In addition, the MTU specified for a particular route should not be larger
than the smallest MTU supported by any system used as an IP router for
that route. If you specify a larger size, performance may degrade as
systems attempt to divide the IP datagrams into smaller fragments.
Chapter 2. Configuring TCP/IP

For additional information about setting the MTU, see Appendix A.
Configuring a Physical Line for TCP/IP Communication.
Preferred binding interface
The preferred binding interface allows administrators to choose which of the
TCP/IP interfaces that they prefer the route to be bound to or on. This
provides the administrator with more flexibility to route traffic over a specific
interface. The interface is preferred because the route is bound to the
indicated interface if the interface is active. If the indicated interface is not
active, then a best-match-first algorithm is used in determining which
interface the route is bound.
In Figure 13, a preferred binding interface of *NONE has been defined. By
using this definition, the user allows the TCP/IP protocol stack to choose an
interface to bind this route to, using a best-match-first algorithm.
Adding TCP/IP routes
You must define routes for any TCP/IP network, including subnetworks, with
which you want to communicate. You do not need to define routes for the
TCP/IP network that your AS/400 system is directly attached to when you
are using an AS/400 adapter.
Manual configuration of the routes that tell TCP/IP how to reach the local
networks is not required. AS/400 TCP/IP generates these routes
automatically from the configuration information for the interfaces every time
TCP/IP is started. In other words, the direct route to the network, which has
an interface attached, is automatically created when you add the interface.
To display all routing entries, including direct routes, use the Network Status
(NETSTAT) command after starting TCP/IP.
To add a route, type option 2 on the Configure TCP/IP menu. The Work
with TCP/IP Routes display (Figure 13) is shown.
Work with TCP/IP Routes
Type options, press Enter.
1=Add
2=Change
4=Remove

System:

SYSNAM890

5=Display

Route
Subnet
Opt Destination
Mask
_
________________ _______________
_
*DFTROUTE
*NONE

Next
Hop
_______________
9.4.73.193

Preferred
Interface
*NONE

Figure 13. Work with TCP/IP Routes Display

Type option 1 (Add) at the input-capable top list entry on that display to go
to the Add TCP/IP Route (ADDTCPRTE) display, as shown in Figure 14 on
page 35.
(To go directly to this display, type the ADDTCPRTE command on any
command line and press F4.)

OS/400 TCP/IP Configuration and Reference V4R4

Add TCP/IP Route (ADDTCPRTE)
Type choices, press Enter.
Route destination . . . . .
Subnet mask . . . . . . . .
Type of service . . . . . .
Next hop . . . . . . . . . .
Preferred binding interface
Maximum transmission unit .
Route metric . . . . . . . .
Route redistribution . . . .
Duplicate route priority . .

F3=Exit
F4=Prompt
F24=More keys

.
.
.
.
.
.
.
.
.

. > '9.4.6.128'
. > '255.255.255.128'
. *NORMAL
*MINDELAY, *MAXTHRPUT...
. > '9.4.73.193'
.
*NONE
.
576
576-16388, *IFC
.
1
1-16
.
*NO
*NO, *YES
.
5
1-10

F5=Refresh

F12=Cancel

Bottom
F13=How to use this display

Figure 14. Add TCP/IP Routes Display

Note: Any changes that you make to the routing information take effect
immediately.
Work with TCP/IP Routes
Type options, press Enter.
1=Add
2=Change
4=Remove
5=Display
Opt
_
_
_

Route
Destination
________________
*DFTROUTE
9.4.6.128

Subnet
Mask
_______________
*NONE
255.255.255.128

Next
Hop
_______________
9.4.73.193
9.4.73.193

Preferred
Interface
*NONE

Figure 15. Work with TCP/IP Routes Display

Multiple Default Routes
Default routes are used to route data that is being addressed to a remote
destination and that does not have a specific route defined. Default routes
are based on the availability of the next hop router and the type of service
(TOS). If no specific TOS is requested, the first available default route with
TOS of *NORMAL is used.
If a default route is not defined, only the networks explicitly defined by any
non-default routes appear as though TCP/IP can reach them, and
datagrams bound for any undefined networks are not sent.
Note: A default route cannot have a subnetwork; therefore, you must leave
the subnet mask at the default value of *NONE.
Consult “Multiple Routes” on page 84 for further information about multiple
default routes and the type of service (TOS) parameter.

Chapter 2. Configuring TCP/IP

Step 4—Configuring TCP/IP attributes
To configure the TCP/IP attributes, type option 3 on the Configure TCP/IP menu.
The Change TCP/IP Attributes (CHGTCPA) display is shown (Figure 16).
Change TCP/IP Attributes (CHGTCPA)
Type choices, press Enter.
TCP keep alive . . . . .
TCP urgent pointer . . .
TCP receive buffer size
TCP send buffer size . .
UDP checksum . . . . . .
IP datagram forwarding .
IP source routing . . .
IP reassembly time-out .
IP time to live . . . .
ARP cache timeout . . .
Log protocol errors . .

.
.
.
.
.
.
.
.
.
.
.

120
*BSD
8192
8192
*YES
*YES
*YES
10
64
5
*YES

1-40320, *SAME, *DFT
*SAME, *BSD, *RFC
512-8388608, *SAME, *DFT
512-8388608, *SAME, *DFT
*SAME, *YES, *NO
*SAME, *YES, *NO
*SAME, *YES, *NO
5-120, *SAME, *DFT
1-255, *SAME, *DFT
1-1440, *SAME, *DFT
*SAME, *YES, *NO

Figure 16. Change TCP/IP Attributes Display

For information about the various parameters for this command, see the online
help. In this step only the IP Datagram Forwarding (IPDTGFWD) parameter is
discussed.
IP Datagram Forwarding
Specifies whether your system should forward datagrams destined for other
networks. The default value is *NO.

Step 5—Configuring TCP/IP Remote System Information (X.25)
Note: If you are not using use X.25, then proceed to “Step 6—Configuring TCP/IP
Host Table Entries” on page 38.
If you use an X.25 connection to reach TCP/IP hosts with a public or private packet
switched data network (PSDN), you need to add remote system information for
each remote TCP/IP host. You must define the X.25 network address of each
system if you use a switched virtual circuit (SVC). If a permanent virtual circuit
(PVC) is set up by the network connecting your system with your remote TCP/IP
partner, you need to know the local logical channel identifier of this PVC.
Adding Remote System Information (X.25)
To add an X.25 remote system address, type option 5 on the Configure
TCP/IP menu. The Work with the TCP/IP Remote System Information
display appears, as shown in Figure 17 on page 37.

OS/400 TCP/IP Configuration and Reference V4R4

Work with TCP/IP Remote System Information
Type options, press Enter.
1=Add
4=Remove
5=Display
Opt
_

Internet
Address
_______________

Network
Address

PVC

System: SYSNAM890

Reverse
Charges

(No remote system information)

Figure 17. Work with Remote System (X.25) Information

Type option 1 (Add) at the input-capable top list entry to go to the Add TCP/IP
Remote System (ADDTCPRSI) display, as shown in Figure 18.
Add TCP/IP Remote System (ADDTCPRSI)
Type choices, press Enter.
Internet address . . . . . . . . > '9.4.73.66'
Network address . . . . . . . . > 40030002
PVC logical channel identifier
X.25 reverse charge . . . . . . *NONE

001-FFF
*NONE, *REQUEST, *ACCEPT

Additional Parameters
Default packet size:
Transmit packet size
Receive packet size
Default window size:
Transmit window size
Receive window size

F3=Exit
F4=Prompt
F24=More keys

. . . . .
. . . . .

*LIND
*LIND

*LIND, 64, 128, 256, 512...
*LIND, *TRANSMIT, 64, 128...

. . . . .
. . . . .

*LIND
*LIND

1-15, *LIND
1-15, *LIND, *TRANSMIT

F5=Refresh

F12=Cancel

Bottom
F13=How to use this display

Figure 18. Add Remote System (X.25) Information

The network controller used by AS/400 TCP/IP does not allow you to specify X.25
user facilities. However, some of the values usually configured on a controller, using
the ADDTCPRSI command, allow you to configure each X.25 remote system.
These values include reverse charging, packet sizes, and window sizes.
Use the following CL command is used to enter the information as shown in the
display above:
ADDTCPRSI INTNETADR('9.4.73.66')
NETADR(40030002)

Notes:
1. Specifying remote system information for an X.25 DDN interface causes that
information to be used instead of the DDN conversion algorithm. The DDN
conversion algorithm is used only for a connection with DDN specified as *YES
when you try to connect to a host that is not defined in the remote system

Chapter 2. Configuring TCP/IP

information. If DDN is specified as *YES on the X.25 connection, you should not
specify remote system information for that interface or its associated DDN
network systems.
2. A routing error occurs when both of the following are true:
v The remote system information associated with the Internet address is an
extended data terminal equipment (DTE) address.
v The configured X.25 interface’s line does not support X.25 extended
addressing.
Note: Any changes that you make to the remote system information take effect
immediately.

Step 6—Configuring TCP/IP Host Table Entries
Each computer system in your network is called a host. The host table allows you
to associate a host name to an Internet address. This step gives instruction for
configuring a host table and host table entries. However, you should determine
early in the configuration planning if a host table or a Domain Name System (DNS)
server is the best option for you in managing host name and IP address
translations.
Whenever possible, a DNS server should be used as a replacement for, or in
addition to, the local host table. The DNS server is a single source for host names,
which is one reason that it is often preferred over host tables, especially for larger
networks. For more information about DNS server support for your AS/400 system,
see “Chapter 18. AS/400 Domain Name System (DNS)” on page 421.
The local host table on your AS/400 system contains a list of the Internet addresses
and related host names for your network. Host tables map Internet addresses to
TCP/IP host names. Host tables allow users to use an easily remembered name for
a system in a network without having to remember the Internet address.
To configure the mapping of host names to Internet addresses, you can use three
different options on the Configure TCP/IP menu. You can use only one or a
combination of all three to obtain the host name processing you need for your
network. The three options on the Configure TCP/IP menu related to Internet
address mappings are:
1. Option 10 (Work with TCP/IP host table entries) to create your own host table.
The Work with Host Table Entries display is shown in Figure 19 on page 39.
2. Option 11 (Merge TCP/IP host table) to merge or convert a host table sent from
another system.
For more information about merging and converting host tables, see “Merging
TCP/IP Host Tables” on page 75.
3. Option 12 (Change TCP/IP domain information) to call the following new
command, CHGTCPDMN.
Note: You can start TCP/IP client functions, such as FTP, by specifying the Internet
address directly without using the host table.
For more information about managing host tables, including host file formats, and
merging host tables, see “Managing TCP/IP Host Tables” on page 73.

OS/400 TCP/IP Configuration and Reference V4R4

Adding an Entry to the Host Table
The Add TCP/IP Host Table Entry display provides fields for an Internet address,
associated host name, and an optional text description.
To add an entry to your local host table, type option 10 on the Configure TCP/IP
menu. The Work with TCP/IP Host Table Entries display is shown in Figure 19.
Work with TCP/IP Host Table Entries
Type options, press Enter.
1=Add
2=Change
4=Remove
Opt
_
_

Internet
Address
_______________
127.0.0.1

5=Display

System: SYSNAM890

7=Rename

Host
Name
LOOPBACK
LOCALHOST

Figure 19. Work with TCP/IP Host Table Entries Display

Note: Just as AS/400 TCP/IP automatically creates a LOOPBACK interface, it also
automatically adds an entry to your local host table to associate the IP
address 127.0.0.1 with the host names LOOPBACK and LOCALHOST. Type
option 1 (Add) at the input-capable top list entry to show the Add TCP/IP
Host Table Entry display.

Work with TCP/IP Host Table Display
Figure 20 and Figure 21 on page 40 show how the host table looks after you enter
all hosts explicitly known.
Work with TCP/IP Host Table Entries
Type options, press Enter.
1=Add
2=Change
4=Remove
Opt
_
_
_
_
_
_
_
_
_
_
_
_
_
_

Internet
Address
_______________
9.4.6.129
9.4.6.134
9.4.6.138
9.4.6.252
9.4.73.65
9.4.73.66
9.4.73.129
9.4.73.130
9.4.73.193
9.4.73.198
9.4.73.206
9.4.73.207
9.4.73.208

5=Display

System:

SYSNAM890

7=Rename

Host
Name
ROUTER2
HPUX
SPARKY
MVAX
XSYSNAM890
XSYSNAM456
ESYSNAM890
ESYSNAMRS
ROUTER1
SYSNAMRS
ITALY
HOLLAND
ENGLAND

More...

Figure 20. Work with Host Table Entries, Display 1 of 2

Chapter 2. Configuring TCP/IP

Work with TCP/IP Host Table Entries
Type options, press Enter.
1=Add
2=Change 4=Remove
Opt
_
_
_
_
_
_

Internet
Address
_______________
9.4.73.211
9.4.73.212
9.4.73.214
9.4.191.76
127.0.0.1

5=Display

System:

SYSNAM890

7=Rename

Host
Name
BERN
SYSNAM890
MACIAN
DNS
LOOPBACK
LOCALHOST

Figure 21. Work with Host Table Entries, Display 2 of 2

The AS/400 TCP/IP host table is shipped with the LOOPBACK entry. The
LOOPBACK entry has an Internet address of 127.0.0.1 and two host names:
LOOPBACK and LOCALHOST.
The 127.0.0.1 Internet address can be changed (CHGTCPHTE) and a different one
can be added (ADDTCPHTE). The local table command processing programs
ensure that any LOOPBACK host name added or changed in the host table is in
the range of 127.0.0.1 to 127.255.255.254. Multiple loopback host table entries are
allowed in the AS/400 host table.
You may alter the LOOPBACK host name or add additional host names using the
(CHGTCPHTE) command.
If the LOOPBACK or LOCALHOST name is changed or removed from the host
table, the name is not valid, unless the domain name server has a LOOPBACK
entry that specifies this value as a host name.
You can define up to four names for each Internet address. If the TCP/IP host is in
your local domain, then it is not necessary to qualify the host with the domain
name. As long as a TCP/IP host is in your local domain, you need only to enter the
host name with the host table entry.
However, if you would like to add TCP/IP hosts that are outside of your local
domain, you need to add these TCP/IP hosts as fully qualified. The fully qualified
host name of SYSNAMEND.ENDICOTT.IBM.COM shows this as an example in Figure 22
on page 41.

OS/400 TCP/IP Configuration and Reference V4R4

Work with TCP/IP Host Table Entries
Type options, press Enter.
1=Add
2=Change
4=Remove
Opt
_
_
_
_
_
_
_

Internet
Address
_______________
9.4.73.211
9.4.73.212
9.4.73.214
9.4.191.76
9.125.87.127
127.0.0.1

5=Display

System:

SYSNAM890

7=Rename

Host
Name
BERN
SYSNAM890
MACIAN
DNS
SYSNAMEND.ENDICOTT.IBM.COM
LOOPBACK
LOCALHOST

Figure 22. Example of a Fully Qualified Host Table Entry

Additional host names are useful as alternative nicknames. See the examples in
Figure 23.
Host names need not be unique. When searching the host table with a duplicate
host name, the result is random. However, IP addresses have to be unique. The
uniqueness of the IP address is enforced at the time you try to add a new entry to
the host table.
Note: An IP address cannot be used as a host name.
Work with TCP/IP Host Table Entries
Type options, press Enter.
1=Add
2=Change
4=Remove
Opt
_
_
_

_
_
_

5=Display

System:

SYSNAM890

7=Rename

Internet
Host
Address
Name
_______________
9.4.73.211
BERN
9.4.73.212
SYSNAM890
M03
F25
MYSYSTEM
9.4.73.214
MACIAN
9.4.191.76
DNS
9.4.73.198
SYSNAMRS

Figure 23. Multiple Host Names

To remove one of the additional host names, select option 2 to change the selected
host table entry. Type *BLANK over the host name to remove it.
Note: The fully qualified host name is used when sending mail between two
TCP/IP hosts.
Notice in the example that the name of AS/400 system SYSNAM890 is in the host
table too. There are several reasons to put your host name in the host table:
v You may want to use your host name when using FTP, TELNET, or PING to test
your own system’s configuration.

Chapter 2. Configuring TCP/IP

v Simple Mail Transfer Protocol (SMTP) requires your host name to be in the host
table or on a domain name server.
v You may want to use your host table on other systems in the network. Your host
name must be in the host table on those systems so they can refer to your
system by name.
v Applications written to use host table lookup routines may require this
information.
When you are finished working with the host table, press F3 (Exit) or F12 (Cancel).

AnyNet/400: APPC over TCP/IP
Advanced program-to-program communication (APPC) over TCP/IP support allows
Common Programming Interface (CPI) Communications or Intersystem
Communications Function (ICF) applications to run over TCP/IP with no changes.
To use the APPC over TCP/IP support, the logical unit (LU) name or the remote
location that your application uses must be mapped to an Internet address. For
APPC over TCP/IP support, the host table is configured to map Internet addresses
to LU names. To do this, you can update the TCP/IP host table using the
configuration menus. The format for the host name is:
LUNAME.NETID.SNA.IBM.COM

Step 7—Configuring the Local Domain and Host Name
Within TCP/IP, the primary name associated with your system (your system can
have more than one name) is called your local domain and host name. The
combination of the local domain and host name forms a fully-qualified host name.
The fully qualified host name is the name by which your system is known and
identified in the TCP/IP domain. The local domain name is also used by sockets to
help in host name resolution at the Domain Name System (DNS) server. The Post
Office Protocol (POP) and Simple Mail Transfer Protocol (SMTP) mail servers
require that the local domain and host name be configured. It is used, but not
required, by line printer requester (LPR), File Transfer Protocol (FTP), and Simple
Network Management Protocol (SNMP).
A domain name consists of labels that are separated by periods, for example,
SYSNAM890.ROCHESTER.IBM.COM. For hosts, the first label in a domain name
is the name of a host that belongs in the domain identified by the other labels. In
this example, host SYSNAM890 belongs to the domain ROCHESTER.IBM.COM.
SYSNAM890.ROCHESTER.IBM.COM is known as the host’s fully qualified domain
name.
To define a local domain name and a host name, use option 12 (Change TCP/IP
domain information) from the Configure TCP/IP menu (Figure 10 on page 28). Refer
to “Domain and Host Name” on page 9 for a more detailed discussion of domain
names.
You may need to configure the local domain name if you use a DNS server that
requires a fully qualified host name to resolve an Internet address. “Chapter 18.
AS/400 Domain Name System (DNS)” on page 421 provides more information on
how to do that.
The AS/400 TCP/IP applications concatenate the local domain name to the host
name if a period is not used at the end of the domain name. See “Concatenating
the Domain Name to the Host Name” on page 437 for an example.

OS/400 TCP/IP Configuration and Reference V4R4

To change the local domain name, type option 12 on the Configure TCP/IP menu.
The Change TCP/IP domain information display is shown in Figure 24.
Change TCP/IP Domain (CHGTCPDMN)
Type choices, press Enter.
Host name . . . . . . . . . . .

SYSNAM890

Domain name . . . . . . . . . .

SYSNAM123.IBM.COM

Host name search priority . . .
Domain name server:
Internet address . . . . . . .

*LOCAL

*REMOTE, *LOCAL, *SAME

'9.4.73.129'

Figure 24. Change TCP/IP Domain Information (CHGTCPDMN)

Notes:
1. Changes that you make using the Change TCP/IP domain information
(CHGTCPDMN) command take effect immediately.
2. The local domain name is used by many applications including PING. PING
appends the local domain to a host name if a domain is not specified or if a
period (.) does not appear at the end of the specified host name.

Domain Name System (DNS) Server
The conversion from host name to Internet address can be performed by using the
host table on the local system or by defining a Domain Name System server, or
DNS server.
In large networks with large host tables, it is more convenient to have DNS servers
than to have a complete copy of the host table on every host in the network.
A DNS server maintains the host table for an entire TCP/IP domain. This prevents
each single host from having to maintain its own local host table.
You can configure your AS/400 system to use both a DNS server and your local
host table, but they are not mutually exclusive. You can also specify whether the
domain name server or your local host table is searched first.
For more information about how the Domain Name System works and how to
configure a DNS server, see “Chapter 18. AS/400 Domain Name System (DNS)” on
page 421.

Step 8—Starting TCP/IP and TCP/IP Servers
Before any TCP/IP services are available on the AS/400 system, TCP/IP processing
must be initialized and activated. To start TCP/IP, you have two options:
1. Select option 3 from the TCP/IP Administration menu (GO TCPADM),
2. Enter the Start TCP/IP (STRTCP) command.

Chapter 2. Configuring TCP/IP

The STRTCP command initializes and activates TCP/IP processing, starts the
TCP/IP interfaces, and starts the TCP/IP server jobs. Only TCP/IP interfaces with
AUTOSTART *YES are started at STRTCP time. Allow a few moments for TCP/IP
to start, and then check to see if the QTCPIP job has started.
Option 20 of the TCP/IP Administration menu allows you to display the jobs related
with TCP/IP. You can also use the following command:
WRKACTJOB SBS(QSYSWRK) JOB(QT*)

The job QTCPIP should be displayed.
Messages indicating that TCP/IP has been started are sent to the QTCP and
QSYSOPR message queues. To check for the successful start of TCP/IP, enter
either of these commands:
DSPMSG QSYSOPR
DSPMSG QTCP

Figure 25 contains a sample of the messages that are issued.
STRTCP issued by job 007138/DJONES/DSP02.
QTCPIP job started.
127.0.0.1 interface started.
QTCPIP job starting 9.5.5.162 interface.
127.0.0.2 interface started.
SNMP Server starting.
TELNET Server starting
FTP Server starting
SMTP Server starting
POP Server starting
LPD Server starting
9.5.5.162 interface started.
STRTCP completed successfully.

Figure 25. Sample Messages from STRTCP with All Applications Autostarted

If the QTCPIP job does not start, look for spooled job logs. Generally, the user for
these job logs is QTCP. Use the Work with Spooled Files (WRKSPLF) command
and specify QTCP for the user (WRKSPLF QTCP) to find the logs.
Application Servers: The TCP/IP application server jobs run under subsystem
QSYSWRK. Several types of TCP/IP server jobs run in the QSYSWRK subsystem.
They are the server jobs for TELNET, POP, FTP, SMTP, LPD, BOOTP, TFTP,
RouteD, REXEC, and SNMP.
The STRTCP command starts the server jobs for an application if the automatic
start attribute for that server is equal to *YES. To change the autostart attribute for
an application, do either of the following:
v Select option 2 from the TCP/IP Administration menu
v Option 20 from the TCP/IP Configuration menu
Using the Start TCP/IP Server (STRTCPSVR) command starts the servers
individually or together. You can monitor the jobs with option 20 (Work with TCP/IP
jobs in QSYSWRK subsystem) from the TCP/IP Administration menu.
If you want TCP/IP processing and any related TCP/IP servers to start automatically
at the initial program load (IPL), add STRTCP to the QSTRUP CL program.

OS/400 TCP/IP Configuration and Reference V4R4

Note: If they are installed, the Client Access host servers are automatically started
when TCP/IP is started.
|
|
|
|
|

Changing the IPL Start-Up Program The autostart job in the controlling subsystem
transfers control to the program specified in the system value QSTRUPPGM. You
can tailor this program. For instructions on how to create your own IPL start-up
program, see the OS/400 Work Management book located in the AS/400 Online
Library at the following URL address: http://www.as400.ibm.com/infocenter.
REMINDER: Host Table Conversion: If you had a pre-V3R1M0 version of TCP/IP
installed on your AS/400 and you had a local host table with more than 75 entries,
use one of the host table configuration commands, such as CHGTCPHTE or
MRGTCPHT before you run the STRTCP command. Using the host table
configuration commands converts pre-V3R1M0 host tables to the new format
without affecting the performance of the STRTCP command processing.

TCP/IP Jobs
Jobs started by the Start TCP/IP (STRTCP) command are listed in Table 2.
Table 2. Jobs Used by TCP/IP

Job Name

Description

QAPPCTCP

APPC over TCP/IP applications

QTBOOTP

BOOTP server

QTCPIP

Main TCP/IP job

QTFTPxxxxx

FTP server (there may be several)

QTGTELNETS

TELNET server (there may be several)

QTRTDxxxxx

RouteD server

QTRXCxxxx

REXEC server (there may be several)

QTSMTPCLNT

SMTP client

QTSMTPSRVR

SMTP server

QTSMTPBRCL

SMTP bridge client

QTSMTPBRSR

SMTP bridge server

QTTFTxxxxx

TFTP server (there may be several)

QTMSNMP

SNMP server

QTMSNMPRCV

SNMP server

QSNMPSA

SNMP server

QTLPDxxxxx

LPD server (there may be several)

QTPOxxxxxx

POP server (there may be several)

QTPPANSxxx

Dial-in (*ANS) support (PPP)

QTPPDIALxx

Dial-out (*DIAL) support (PPP)

ADMIN and DEFAULT

ICS (HTTP) server

QTWSGxxxxx

Workstation gateway (there may be several)

Chapter 2. Configuring TCP/IP

Table 2. Jobs Used by TCP/IP (continued)
Job Name

Description

Note:
1. There may be other jobs running in the QSYSWRK subsystem that have nothing to do
with TCP/IP.
2. The TCP/IP jobs in QSYSWRK run under the QTCP user profile, with two exceptions:
the TFTP server runs under the QTFTP profile, and the workstation gateway server runs
under the QTMTWSG profile.
3. To use APPC over TCP/IP applications, you must set the network attribute Allow AnyNet
(ALWANYNET) to *YES.

End TCP/IP (ENDTCP):

ATTENTION!
No confirmation display appears when you enter ENDTCP is entered.
Therefore, you must use the ENDTCP command carefully. The default for the
ENDTCP command is to immediately end all TCP/IP processing on the
AS/400 system that you are working on.

Use the End TCP/IP (ENDTCP) command to end all TCP/IP processing.
The command can be issued from the command line or by using option 4 on the
TCP/IP Administration menu. To display this menu, enter GO TCPADM on the
command line.

Step 9—Verifying the TCP/IP Connection
To verify the TCP/IP connection from your AS/400 system to the network, use the
PING (VFYTCPCNN) function.
1. To test the TCP/IP code without sending anything out of the token-ring adapter,
specify the special host name LOOPBACK as follows:
PING LOOPBACK

2. To test the TCP/IP code, token-ring adapter, and token-ring connection, specify
the Internet address of the local adapter, as defined in the host table, as follows:
PING RMTSYS(*INTNETADR)
INTNETADR('9.4.73.212')

Or you may enter:
PING RMTSYS(SYSNAM890)

This command sends data out onto the token-ring line, which the local adapter
receives again as if the data is from the TCP/IP network.
Figure 26 on page 47 shows the results from a successful connection
verification.

OS/400 TCP/IP Configuration and Reference V4R4

> ping '9.4.73.212'
Verifying connection to host system 9.4.73.212.
PING request 1 from 9.4.73.212 took 24 ms. 256 bytes.
PING request 2 from 9.4.73.212 took 11 ms. 256 bytes.
PING request 3 from 9.4.73.212 took 31 ms. 256 bytes.
PING request 4 from 9.4.73.212 took 11 ms. 256 bytes.
PING request 5 from 9.4.73.212 took 12 ms. 256 bytes.
Round-trip (in milliseconds) min/avg/max = 11/17/31
Connection verification statistics: 5 of 5 successful

TTL
TTL
TTL
TTL
TTL

64.
64.
64.
64
64.

(100 %).

Figure 26. Successful PING Messages

3. If the PING operation is successful, you should see messages similar to those
in Figure 26.
If the PING operation is unsuccessful, you should see messages similar to
those in Figure 27.
If you receive an unsuccessful PING message, check your configuration steps.
Also check that the configuration at the remote system is correct and that the
remote system is not powered down. For additional information about identifying
the cause for an unsuccessful connection verification, see 437.
> ping '9.4.73.198'
Verifying connection to host system 9.4.73.198.
No response from host within 1 seconds for connection
No response from host within 1 seconds for connection
No response from host within 1 seconds for connection
No response from host within 1 seconds for connection
No response from host within 1 seconds for connection
Connection verification statistics: 0 of 5 successful

verification
verification
verification
verification
verification
(0 %).

1.
2.
3.
4.
5.
Bottom

Figure 27. Unsuccessful PING Messages

Note: A datagram sent by TCP or UDP to a system with the name LOOPBACK
does not actually leave the system. The IP layer, instead, returns the
datagram to the TCP or UDP layer from which it came. The other layers then
treat the datagram as a normal incoming datagram. The LOOPBACK host
name can be used with any TCP/IP command requiring a system name,
such as PING or FTP (or any TCP or UDP application including user-written
applications). Using the LOOPBACK default host name provides an ability to
test TCP/IP applications without actually connecting to a physical network.
The AS/400 system defines LOOPBACK as the default host name by automatically
creating an entry in the local host table.

Verifying Additional TCP/IP Connections
Once TCP/IP is configured on the AS/400 system, and the initial connection is
verified, you will probably want to add more systems to your network. When you
connect additional systems to your network, you also need to verify their TCP/IP
connection. The examples in the following paragraphs show you how to verify a
remote TCP/IP connection.

Chapter 2. Configuring TCP/IP

Use the system menus or the Verify TCP/IP Connection (VFYTCPCNN or PING)
command to verify your system’s ability to communicate with a remote system using
TCP/IP.
Note: PING uses the Internet Control Message Protocol (ICMP) to send data to a
host’s Internet address and waits for a response. The user command to
perform this verification is called PING (Packet InterNet Groper) on
non-AS/400 systems. On an AS/400 system, use either the PING command
or the VFYTCPCNN command.
To verify TCP/IP connections, perform the three steps below in the order in which
they are listed:
1. Type VFYTCPCNN and then press F4.
The display for the VFYTCPCNN command appears (Figure 28).
2. Type the name of a remote system as defined in your host table or as defined
by your domain name server.
If you prefer to use an Internet address, type the address enclosed in
apostrophes. You can also type *INTNETADR to be prompted for the Internet
address.
3. Press F10 to view or change the additional parameters.
As you can see in Figure 29 on page 49, the system defaults are to send five
packets of 256 bytes each and to wait 1 second for a response on each packet.

Verify TCP/IP Connection (VFYTCPCNN)
Type choices, press Enter.
Remote system . . . . . . . . . ____________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________

Figure 28. Verify TCP/IP Connection

OS/400 TCP/IP Configuration and Reference V4R4

Verify TCP/IP Connection (PING)
Type choices, press Enter.
Remote system . . . . . . . . . sysnam36.sysnam123.ibm.com__________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
Remote internet address . . . . _____________________________
Additional Parameters
Message mode:
Response message detail . .
Summary, if response errors
Packet length (in bytes) . . .
Number of packets . . . . . .
Wait time (in seconds) . . . .
Local internet address . . . .
Type of service . . . . . . .
IP time to live . . . . . . .

F3=Exit
F4=Prompt
F24=More keys

.
.
.
.
.
.
.
.

F5=Refresh

*VERBOSE
*VERBOSE, *QUIET
*COMP
*COMP, *ESCAPE
256
8-512
5
1-999
1
1-120
*ANY________
*NORMAL
*MINDELAY, *MAXTHRPUT...
*DFT
1-255, *DFT

F12=Cancel

More...
F13=How to use this display

Figure 29. Verify TCP/IP Connection, Additional Parameters

Verifying TCP/IP Connections with Host Name—Example
In this example, sending five packets of 256 bytes each verifies the connection to
the remote system SYSNAM36. The local system waits 1 second for a response to
each packet that is sent.

Chapter 2. Configuring TCP/IP

Verify TCP/IP Connection (PING)
Type choices, press Enter.
Remote system . . . . . . . . . > SYSNAM36.SYSNAM123.IBM.COM_____________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
Additional Parameters
Message mode:
Response message detail . .
Summary, if response errors
Packet length (in bytes) . . .
Number of packets . . . . . .
Wait time (in seconds) . . . .
Local internet address . . . .
Type of service . . . . . . .
IP time to live . . . . . . .

F3=Exit
F4=Prompt
F24=More keys

.
.
.
.
.
.
.
.

F5=Refresh

*VERBOSE
*VERBOSE, *QUIET
*COMP
*COMP, *ESCAPE
256
8-512
5
1-999
1
1-120
*ANY________
*NORMAL
*MINDELAY, *MAXTHRPUT...
*DFT
1-255, *DFT

F12=Cancel

More...
F13=How to use this display

Figure 30. Verifying Connection to Remote System SYS1

Verifying TCP/IP Connections with Internet Address—Example
In this example, (Figure 30) the connection to the remote system at Internet
address 9.4.191.76 is verified using the system defaults for packet length, number
of packets, and wait time.
Verify TCP/IP Connection (PING)
Type choices, press Enter.
Remote system . . . . . . . . . *intnetadr___________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
Remote internet address . . . . > '9.4.191.76'

Figure 31. Verifying Connection to Remote System at Internet Address 9.4.191.76

Step 10—Saving Your TCP/IP Configuration
To save your TCP/IP configuration files, use the following command:
SAVOBJ OBJ(QATOC* QATM*) LIB(QUSRSYS)
DEV(TAP01) OBJTYPE(*FILE)

The associated line descriptions are not saved with this command. Configuration
objects are saved with the system.
To maintain consistency, save all TCP/IP configuration files together.

OS/400 TCP/IP Configuration and Reference V4R4

Note: You do not have to end TCP/IP in order to save the configuration files.
However, you should end TCP/IP before any TCP/IP configuration files are
restored.

TCP/IP Planning Checklists
The following checklists (Table 3 and Table 4) can help you prepare for the
installation and configuration of TCP/IP on your network
v Line description parameters
v Local TCP/IP host information

Line Description Parameters Checklist
Table 3. Line Description Parameters
Line Type

*ELAN

*TRLAN

*WLS

*DDI

Resource name

Local adapter address

Speed

*FR

SSAP (session services
access point)

Maximum frame size

Local manager mode

*X25

*ASYNC

*PPP

*TDLC

Attached non-switched
NWI name

Data link connection ID

Network controller

Connection type

Logical channel identifier

Logical channel type

PVC (permanent virtual
circuit) controller

Local network address

Physical interface type

Packet size

Window size

Attached workstation
controller

Note:
R means the parameter is required
O means OS/400 suggests a default value

Local TCP/IP Host Information Checklist
Table 4. Local TCP/IP Host Information
Interfaces to Local TCP/IP Networks
Interface #1

Interface #2

Interface #3

Chapter 2. Configuring TCP/IP

Table 4. Local TCP/IP Host Information (continued)
Internet address
Line description name
Subnet mask
Interface MTU
Local host name
Local domain name
Domain name server (Internet address)
Default route/next hop (Internet address)
IP datagram forwarding (yes or no)
Explicit Routes to Remote TCP/IP Networks
Route #1

Route #2

Route #3

Internet address
Subnet mask
Next hop (Internet address)
MTU size
Local Host Table Entries: Remote TCP/IP Hosts
Internet address

Host Name #1

Host Name #2

Host Name #3

X.25 / Remote System Information
Host #1

Host #2

Host #3

Internet address
X.25 network address
PVC channel ID
Packet or window size

Sample Network Drawing
The following network illustration can help you as you begin to draw your own
network diagram. By performing this exercise, you will have a clear idea of how to
attach your AS/400 system to the other systems in the network.

OS/400 TCP/IP Configuration and Reference V4R4

Figure 32. Sample TCP/IP Network

Chapter 2. Configuring TCP/IP

OS/400 TCP/IP Configuration and Reference V4R4

Chapter 3. TCP/IP: Operation, Management, and Advanced
Topics
This chapter discusses managing your network by using the NETSTAT command,
and the maintenance of host tables. In addition, this chapter covers other topics
beyond those that are required to configure and use TCP/IP on AS/400. This
information may help you to understand and maximize your usage of the AS/400
TCP/IP support.
TCP/IP on an AS/400 system can also be managed by Simple Network
Management Protocol (SNMP). For information about SNMP, see the book, Simple
Network Management Protocol (SNMP) Support, SC41-5412-00.

Network Status
The network status function on the AS/400 system allows you to get information
about the status of TCP/IP network interfaces, routes, and connections on your
local system. This function also allows you to end TCP/IP connections and to start
or end TCP/IP interfaces.
NETSTAT displays the current TCP/IP protocol stack information. This information
does not necessarily match the configuration data you see when using the
Configure TCP/IP (CFGTCP) menu. In most cases, the NETSTAT command
displays more information than the configuration data. In some cases, the
configuration data might even change.
The reason for such a change is that the AS/400 TCP/IP dynamically creates some
information, such as *DIRECT routes, when TCP/IP starts. A change may also
occur if the configuration data that was sent to TCP/IP when it starts is changed
dynamically by TCP/IP applications that run after you start TCP/IP. Several types of
processing alter the initial TCP/IP configuration:
v Internet Control Message Protocol (ICMP) requests
v Sockets ioctl system calls
v Simple Network Management Protocol (SNMP) requests
v AS/400 TCP/IP internal processing

Work with TCP/IP Network Status Menu
The Work with TCP/IP Network Status menu allows you to work with the various
network status functions.
To display the Work with TCP/IP Network Status menu, take these steps:
1. Type the WRKTCPSTS (Work with TCP/IP Network Status) command or the
NETSTAT (Network Status) command.
2. Press the Enter key. (See Figure 33 on page 56.)

Work with TCP/IP Network Status
Select one of the following:

System:

SYSNAM04

1. Work with TCP/IP interface status
2. Display TCP/IP route information
3. Work with TCP/IP connection status

Figure 33. Work with TCP/IP Network Status

Work with TCP/IP Interface Status
The Work with TCP/IP Interface Status display, as shown in Figure 34, provides the
most current summary of interface activity. This display allows you to view TCP/IP
interface information for selected interfaces and to start or end TCP/IP interfaces.
To view the Work with TCP/IP Interface Status display, take these steps:
1. Type 1 on the command line of the Work with TCP/IP Network Status menu or
enter the WRKTCPSTS *IFC command.
2. Press the Enter key.

Work with TCP/IP Interface Status
Type options, press Enter.
5=Display details 8=Display associated routes
12=Work with configuration status
Opt

Internet
Address
9.125.87.10
9.125.87.222
127.0.0.1

F3=Exit
F4=Prompt
F13=Sort by column

Network
Address
9.125.87.0
9.125.87.0
127.0.0.0

System:

9=Start

SYSNAM04

10=End

Line
Interface
Description Status
TRNLINE
Active
TESTTRN
Active
*LOOPBACK
Active

F5=Refresh
F11=Display line information
F24=More keys

Bottom
F12=Cancel

Figure 34. Work with TCP/IP Interface Status, Display 1 of 2

Press F11 to change the contents of the display to include the subnet mask, type of
service, maximum transmission unit (MTU), and line type, as shown in Figure 35 on
page 57.

OS/400 TCP/IP Configuration and Reference V4R4

Work with TCP/IP Interface Status
Type options, press Enter.
5=Display details
8=Display associated routes
12=Work with configuration status
Opt

Internet
Address
9.125.87.10
9.125.87.222
127.0.0.1

Subnet
Mask
255.255.255.0
255.255.255.0
255.0.0.0

Type of
Service
*MAXTHRPUT
*NORMAL
*NORMAL

System:

9=Start

SYSNAM04

10=End

Line
MTU Type
1989 *TRLAN
1989 *TRLAN
576 *NONE

Figure 35. Work with TCP/IP Interface Status, Display 2 of 2

Starting TCP/IP Interfaces
TCP/IP interfaces are started in one of the following ways:
v The Work with TCP/IP Interface Status displays are reached by:
– Option 1 on the Configure TCP/IP (CFGTCP) menu
– Option 1 on the Network Status (NETSTAT or WRKTCPSTS) menu
v The Start TCP/IP Interface (STRTCPIFC) command
v Using the Operations Navigator interface
Note: You can start TCP/IP interfaces through the Operations Navigator
interface wizard. However, this chapter does not document any of the
Operations Navigator functions. See the online help in Operations
Navigator for this information.
To start a TCP/IP interface from the Work with TCP/IP Interface Status menu, type
9 in the option field for each interface that you want to start and press the Enter
key.
To start a TCP/IP interface using the STRTCPIFC command, take these steps:
1. Type STRTCPIFC on the command line and press F4 (Prompt).
2. Type the Internet address of the interface that you want to start and press the
Enter key.
Option 9 on the Work with TCP/IP Interface Status display is used to start both
TCP/IP interfaces and Internet Protocol (IP) over Systems Network Architecture
(SNA) interfaces. For information about starting IP over SNA interfaces, see the
STRIPSIFC (Start IP over SNA Interface) command in the CL Reference (Abridged),
SC41-5722.
Note: When starting the first TCP/IP interface associated with an Integrated
Netfinity Server for AS/400 (also known as File Server Input/Output
Processor and FSIOP) network server description, a considerable amount of
time may pass before the interface becomes active. This is because TCP/IP
activation includes starting the network server. The amount of time that is
required depends mainly on machine use and the size of the processor. To
determine whether the interface has started, view the messages in the
QTCPIP job log and the QSYSOPR message queue.

Chapter 3. TCP/IP: Operation, Management, and Advanced Topics

Ending TCP/IP Interfaces
The ENDTCPIFC (End TCP/IP Interface) command ends an existing TCP/IP
interface immediately. As a result, all TCP/IP connections using this interface also
end immediately. However, the operation of any other TCP or IP over SNA
interface, using the same line description as the interface that is ending, is not
affected.
TCP/IP interfaces can be ended in one of two ways:
v Using the Work with TCP/IP Interface Status display, which is reached by:
– Option 1 on the Configure TCP/IP (CFGTCP) menu
– Option 1 on the Network Status (NETSTAT or WRKTCPSTS) menu
v Using the ENDTCPIFC (End TCP/IP Interface) command
To end a TCP/IP interface from the Work with TCP/IP Interface Status menu:
1. Type 10 in the option field for each interface that you want to end.
2. Press the Enter key.
To
1.
2.
3.

end a TCP/IP interface using the ENDTCPIFC command:
Type ENDTCPIFC on the command line.
Press F4 (Prompt).
Type the Internet address of the interface that you want to end.

4. Press the Enter key.
Option 10 on the Work with TCP/IP Interface Status display is used to end both
TCP/IP interfaces and IP over SNA interfaces. For information about ending IP over
SNA interfaces, see the ENDIPSIFC (End IP over SNA Interface) command in the
CL Reference (Abridged), SC41-5722-03.

Route-to-Interface Binding: Interfaces define direct paths to networks or
subnetworks to which an AS/400 system is directly attached. Routes define indirect
paths. A route identifies the first hop on the path to a network or subnetwork to
which an AS/400 system is not directly attached.
Routes are bound to interfaces through the use of a best-match-first algorithm. This
algorithm is based on the state of the interface, and on the type of service (TOS)
specified for the route and interface. When you end an interface, the routes
associated with the interface can move to another existing active interface if the
following conditions are satisfied:
v If the TOS for the route is something other than *NORMAL, the algorithm looks
for an interface with the same TOS. If an interface with the specified TOS is not
found, an interface with TOS *NORMAL is sought. Again, if one is not found, that
route will not be moved.
v The MTU value for the route that is being moved must be less than or equal to
the MTU value for the active interface.
v The network ID of the interface must be equal to the logical AND of the next hop
for the route and the subnet mask for the interface.
Notes:
1. If the next hop of a route is identical to an interface’s IP address, that route will
never be bound to another interface.
2. When starting interfaces (if all interfaces are currently inactive) routes are bound
to the interfaces with the same best-match-first algorithm. An exception is if the

OS/400 TCP/IP Configuration and Reference V4R4

route is defined with a preferred binding interface. In this case, an attempt is
made to bind the route to the interface that is indicated. If the binding attempt
fails, then the best-match-first algorithm is used.

Display TCP/IP Route Information
The display TCP/IP route information function allows you to view information about
TCP/IP routes.
To display TCP/IP route information:
1. On the Work with TCP/IP Network Status menu, type 2 on the command line or
enter the WRKTCPSTS *RTE command.
2. Press the Enter key.
The first of the two Display TCP/IP Route Information displays appears, as shown in
Figure 36.
Display TCP/IP Route Information

System:

Type options, press Enter.
5=Display details
Opt

Route
Destination
9.125.87.0
9.125.87.0
9.125.109.3
127.0.0.0
*DFTROUTE
*DFTROUTE

F3=Exit
F5=Refresh
F13=Sort by column

Subnet
Mask
255.255.255.0
255.255.255.0
*HOST
255.0.0.0
*NONE
*NONE

F6=Print list
F17=Top

Next
Hop
*DIRECT
*DIRECT
9.125.87.17
*DIRECT
9.125.87.169
9.125.87.250

SYSNAM04

Route
Available
*YES
*YES
*YES
*YES
*YES
*YES

F11=Display route type
F18=Bottom

Bottom
F12=Cancel

Figure 36. Display TCP/IP Route Information, Display 1 of 2

To view the second display, press F11 (Display route type). The route information is
presented as shown in Figure 37 on page 60. To return to the first display, press
F11 (Display next hop).

Chapter 3. TCP/IP: Operation, Management, and Advanced Topics

Display TCP/IP Route Information
Type options, press Enter.
5=Display details
Opt

Route
Destination
9.125.87.0
9.125.87.0
9.125.109.3
127.0.0.0
*DFTROUTE
*DFTROUTE

F3=Exit
F5=Refresh
F13=Sort by column

Type of
Service
*MAXTHRPUT
*NORMAL
*MINDELAY
*NORMAL
*MAXTHRPUT
*NORMAL

F6=Print list
F17=Top

Route
MTU
1989
1989
576
576
1989
1989

System:

SYSNAM04

Route
Route
Type
Source
*DIRECT
*CFG
*DIRECT
*CFG
*HOST
*ICMP
*DIRECT
*CFG
*DFTROUTE *CFG
*DFTROUTE *CFG

F11=Display next hop
F18=Bottom

F12=Cancel

Bottom

Figure 37. Display TCP/IP Route Information, Display 2 of 2

To view detailed information about a specific route, type 5 in the option field next to
the route and press the Enter key.
Routes listed on the Display TCP/IP Route Information display differ from the routes
that are displayed on the Work with TCP/IP Routes display. Only routes with a route
source of *CFG and a route type that is not *DIRECT can be changed with the
Work with TCP/IP Routes display. Similarly, only routes that meet these conditions
can be changed or removed with the CHGTCPRTE or RMVTCPRTE commands.
*CFG means the route was added using AS/400 configuration commands or is a
*DIRECT route. *DIRECT means that the route is to a network or subnetwork to
which this system has a direct physical connection. This route is not defined with an
add route command.

Work with TCP/IP Connection Status
The Work with TCP/IP Connection Status display allows you to display or end a
TCP/IP connection between a local system and a remote system.
To display the Work with TCP/IP Connection Status display:
1. Type 3 on the command line of the Work with TCP/IP Network Status menu or
enter the WRKTCPSTS *CNN command.
2. Press the Enter key.
The first of the three Work with TCP/IP Connection Status displays, as shown in
Figure 38 on page 61.
To display the second and third Work with TCP/IP Connection Status displays,
press F11 (see Figure 39 on page 61 and Figure 40 on page 62). To display port
numbers instead of port service names, press F14.
In Figure 38 on page 61, the connections indicate that the FTP server, SMTP
server, and TELNET server are active and ready to receive connection attempts.

OS/400 TCP/IP Configuration and Reference V4R4

Because no connection has been established yet, the Remote Address and Remote
Port fields contain an asterisk (*). When an application requests a connection to a
listening socket, a new connection is created. The remote Internet address and
remote port are shown for the new connection. The listening socket always remains
in the list of connections.
Work with TCP/IP Connection Status
Local internet address . . . . . . . . . . . :

*ALL

System:

SYSNAM04

Type options, press Enter.
4=End
5=Display details
Opt

Remote
Address
*
*
*
*
*
*
*
*
*
*
9.5.1.180

Remote
Port
*
*
*
*
*
*
*
*
*
*
1211

Local
Port
ftp-con >
telnet
telnet
smtp
lpd
1049
1050
1051
1052
1070
telnet

Idle Time
000:20:41
001:39:00
000:14:27
000:55:23
002:36:29
001:31:01
001:28:02
001:12:05
001:09:52
000:35:53
000:10:17

State
Listen
Listen
Listen
Listen
Listen
*UDP
*UDP
*UDP
*UDP
Listen
Established

F5=Refresh
F11=Display byte counts
F13=Sort by column
F14=Display port numbers
F22=Display entire field
F24=More keys

More...

Figure 38. Work with TCP/IP Connection Status, Display 1 of 3

Work with TCP/IP Connection Status
Local internet address . . . . . . . . . . . :

*ALL

System:

SYSNAM04

Type options, press Enter.
4=End
5=Display details
Opt

Remote
Address
*
*
*
*
*
9.5.1.131
9.5.1.180
9.5.15.134
9.5.15.141
9.130.38.18
9.130.38.74

Remote
Port
*
*
*
*
*
1954
1211
1024
1027
2099
1125

Local
Port
ftp-con >
telnet
telnet
lpd
1070
telnet
telnet
telnet
telnet
telnet
telnet

User
QTCP
QTCP
QTCP
QTCP
BILANSKY
QTCP
QTCP
QTCP
QTCP
QTCP
QTCP

Bytes Out
0
0
0
0
0
48583
32319
403415
3831
509788
680

F5=Refresh
F11=Display connection type
F13=Sort by column
F14=Display port numbers
F22=Display entire field
F24=More keys

Bytes In
0
0
0
0
0
815
4704
226141
236
15394
34
More...

Figure 39. Work with TCP/IP Connection Status, Display 2 of 3

Chapter 3. TCP/IP: Operation, Management, and Advanced Topics

Work with TCP/IP Connection Status
Local internet address . . . . . . . . . . . :

*ALL

System:

SYSNAM04

Type options, press Enter.
4=End
5=Display details
Opt

Remote
Address
*
*
*
*
*
9.5.1.131
9.5.1.180
9.5.15.134
9.130.38.18
9.130.38.74
9.130.38.74

Remote
Port
*
*
*
*
*
1954
1211
1024
2099
1125
1126

Local
Address
*
*
*
*
9.125.87.222
9.125.87.10
9.125.87.10
9.125.87.10
9.125.87.222
9.125.87.10
9.125.87.222

Local
Port
Type
ftp-con > *TCP
telnet
*TCP
telnet
*TCP
lpd
*TCP
1070
*TCP
telnet
*TCP
telnet
*TCP
telnet
*TCP
telnet
*TCP
telnet
*TCP
telnet
*TCP

F5=Refresh
F11=Display connection state
F13=Sort by column
F14=Display port numbers
F22=Display entire field
F24=More keys

More...

Figure 40. Work with TCP/IP Connection Status, Display 3 of 3

Ending TCP/IP Connections
TCP/IP connections and User Datagram Protocol (UDP) sockets can be ended from
the Work with TCP/IP Connection Status display. To do so:
1. Type 4 in the option field for the lines containing the connections that you want
to end.
2. Press the Enter key.
The Confirm End of TCP/IP Connections displays is then presented as shown in
Figure 41 on page 63.

OS/400 TCP/IP Configuration and Reference V4R4

Confirm End of TCP/IP Connections
Local internet address . . . . . . . . . . . :

*ALL

System:

SYSNAM04

Press Enter to confirm your choices for 4=End.
Press F12 to return to change your choices.
Remote
Opt Address
4
9.5.15.134

Remote
Port
1024

F11=Display connection state
F22=Display entire field

Local
Address
9.125.87.10

F12=Cancel

Local
Port
telnet

Type
*TCP

F14=Display port numbers

Bottom

Figure 41. Confirm End of TCP/IP Connections

To end the TCP/IP connections, press the Enter key from the Confirm End of
TCP/IP Connections display.
If you decide not to end a TCP/IP connection or if you want to change your choices,
press F12 (Cancel).

Working with Configuration Status
To work with the line description used by an interface:
1. On the Work with TCP/IP Interface Status menu, type 12 in the option field for
each interface that you want to work with.
2. Press the Enter key.
This option issues the WRKCFGSTS (Work with Configuration Status) command for
the line description associated with the interface. Using the options shown in
Figure 42 on page 64 you can vary a line description on or off, display the Work
with Job menu, and display the line description or mode status.
This option cannot be used for IP over SNA interfaces because IP over SNA does
not use specific line descriptions.

Chapter 3. TCP/IP: Operation, Management, and Advanced Topics

Work with Configuration Status
Position to . . . . .

Starting characters

04/26/94

SYSNAM04
15:55:58

Type options, press Enter.
1=Vary on
2=Vary off
5=Work with job
9=Display mode status ...

8=Work with description

Opt

-------------Job--------------

Description
TRNLINE
TRNLINET
TRNLITCP

Status
ACTIVE
ACTIVE
ACTIVE

QTCPIP

QTCP

007936

Figure 42. Work with Configuration Status

Displaying TCP/IP Network Status Information
In addition to working with network status functions, the Work with TCP/IP Network
Status menu allows you to display current information about your TCP/IP network,
including multicast groups, TCP/IP interfaces, and associated routes, to name a
few.

Display Multicast Groups
To display the multicast groups associated with an interface:
1. On the Work with TCP/IP Interface Status display, type 14 in the option field for
each interface for which you want to see the associated multicast groups.
2. Press the Enter key.
Figure 43 on page 65 illustrates the display of the multicast groups for an Ethernet
interface.
If you have requested multicast group information for more than one interface,
press the Enter key to review the remaining displays.

OS/400 TCP/IP Configuration and Reference V4R4

Display Multicast Host Groups
Interface internet address . . . . . . . . . . . :
Host Group
224.0.0.1
225.4.5.6
233.32.40.51
224.0.0.9
229:200:100:1

F3=Exit
F5=Refresh
F12=Cancel

Hardware Address
01:00:5E:00:00:01
01:00:5E:04:05:06
01:00:5E:20:28:33
01:00:5E:00:00:09
01:00:5E:48:64:01

F6=Print

System:
10.5.5.55

Host Group

F9=Command line

SYSNAM04

Hardware Address

Bottom
F11=Hide hardware address

Figure 43. Display Multicast Host Groups

Displaying TCP/IP Interfaces
To display more detailed information about the TCP/IP interface status for specific
interfaces:
1. On the Work with TCP/IP Interface Status display, type 5 in the option field for
each interface about which you want more information.
2. Press the Enter key.
If you requested status for a token-ring interface, the information displays, as shown
in Figure 44 on page 66.
If you have requested interface status information for more than one interface,
press the Enter key to view the remaining displays.

Chapter 3. TCP/IP: Operation, Management, and Advanced Topics

Display TCP/IP Interface Status
Interface host name . . . . .
Internet address . . . . . .
Subnet mask . . . . . . . .
Network address . . . . . .
Host address . . . . . . .
Directed broadcast address

.
.
.
.
.
.

:
:
:
:
:
:

System:
SYSNAM04
sysnam04.endicott.ibm. >
9.125.87.10
255.255.255.0
9.125.87.0
0.0.0.10
9.125.87.255

Interface status . . . .
Change date/time . . . .
Line description . . . .
Line type . . . . . . . .
Type of service . . . . .
Maximum transmission unit
Automatic start . . . . .

.
.
.
.
.
.
.

:
:
:
:
:
:
:

Active
04/26/94 14:32:32
TRNLINE
*TRLAN
*MAXTHRPUT
1989
*YES

.
.
.
.
.
.
.

TRLAN bit sequencing . . . . . . . . . . . . :

*MSB

Figure 44. Display TCP/IP Interface Status for a Token-Ring Interface

Displaying Associated Routes
To display information about the routes associated with a specific interface:
1. On the Work with TCP/IP Interface Status display, type 8 in the option field for
each interface for which you want to see the associated routes information.
2. Press the Enter key.
The first of two displays with associated route information is shown in Figure 45 on
page 67.
If you have requested associated route information for more than one interface,
press the Enter key to view the remaining displays.

OS/400 TCP/IP Configuration and Reference V4R4

Display Associated Routes
Interface internet address . . . . . . . . . :

System:
9.125.87.10

SYSNAM04

Type options, press Enter.
5=Display details
Opt

Route
Destination
9.125.87.0
*DFTROUTE

F3=Exit
F5=Refresh
F13=Sort by column

Subnet
Mask
255.255.255.0
*NONE

F6=Print list
F17=Top

Next
Hop
*DIRECT
9.125.87.169

Route
Available
*YES
*YES

F11=Display route type
F18=Bottom

Bottom
F12=Cancel

Figure 45. Associated Route Information, Display 1 of 2

Press F11 to show the display that includes the type of service (TOS), maximum
transmission unit (MTU), type, and source.

Displaying Route Details Option
To display detailed information about the route:
1. On the Display Associated Routes display, type 5 in the option field for each
route about which you want more information.
2. Press the Enter key.
Figure 46 on page 68 and Figure 47 on page 68 are examples.

Chapter 3. TCP/IP: Operation, Management, and Advanced Topics

Display TCP/IP Route Details
Route information:
Route destination . . . . . . .
Subnet mask . . . . . . . . . .
Next hop host name . . . . . .
Next hop . . . . . . . . . . .
Type of service . . . . . . . .
Route available . . . . . . . .
Route type . . . . . . . . . .
Route source . . . . . . . . .
Change date/time . . . . . . .
Route maximum transmission unit
Reference count . . . . . . . .

.
.
.
.
.
.
.
.
.
.
.

:
:
:
:
:
:
:
:
:
:
:

Local interface information:
Internet address . . . . . . . . . . . . . :
Subnet mask . . . . . . . . . . . . . . . :
Network address . . . . . . . . . . . . . :

System:

9.125.87.0
255.255.255.0
sysnam04.endicott.ibm. >
*DIRECT
*MAXTHRPUT
*YES
*DIRECT
*CFG
04/26/94 14:32:32
1989
0
9.125.87.10
255.255.255.0
9.125.87.0

Press Enter to continue.
F3=Exit

F6=Print

F12=Cancel

SYSNAM04

More...

F22=Display entire field

Figure 46. Display TCP/IP Route Details, Display 1 of 2

Display TCP/IP Route Details
Interface status . . . . . . . . . . . . . :
Line description . . . . . . . . . . . . . :
Line type . . . . . . . . . . . . . . . . . :

Active
TRNLINE
*TRLAN

System:

SYSNAM04

Figure 47. Display TCP/IP Route Details, Display 2 of 2

Displaying TCP/IP Route Information
To display TCP/IP route information:
1. On the Work with TCP/IP Network Status menu, type 2 on the command line or
enter the WRKTCPSTS *RTE command.
2. Press the Enter key.
The first of the two Display TCP/IP Route Information displays is presented as
shown in Figure 48 on page 69.

OS/400 TCP/IP Configuration and Reference V4R4

Display TCP/IP Route Information

System:

Type options, press Enter.
5=Display details
Opt

Route
Destination
9.125.87.0
9.125.87.0
9.125.109.3
127.0.0.0
*DFTROUTE
*DFTROUTE

F3=Exit
F5=Refresh
F13=Sort by column

Subnet
Mask
255.255.255.0
255.255.255.0
*HOST
255.0.0.0
*NONE
*NONE

F6=Print list
F17=Top

Next
Hop
*DIRECT
*DIRECT
9.125.87.17
*DIRECT
9.125.87.169
9.125.87.250

SYSNAM04

Route
Available
*YES
*YES
*YES
*YES
*YES
*YES

Bottom
F12=Cancel

F11=Display route type
F18=Bottom

Figure 48. Display TCP/IP Route Information, Display 1 of 2

To view the second Display TCP/IP Route Information display, press F11 (Display
route type). The route information is presented in Figure 49. To return to the first
display, press F11 (Display next hop).
Display TCP/IP Route Information
Type options, press Enter.
5=Display details
Opt

Route
Destination
9.125.87.0
9.125.87.0
9.125.109.3
127.0.0.0
*DFTROUTE
*DFTROUTE

F3=Exit
F5=Refresh
F13=Sort by column

Type of
Service
*MAXTHRPUT
*NORMAL
*MINDELAY
*NORMAL
*MAXTHRPUT
*NORMAL

F6=Print list
F17=Top

Route
MTU
1989
1989
576
576
1989
1989

System:

SYSNAM04

Route
Route
Type
Source
*DIRECT
*CFG
*DIRECT
*CFG
*HOST
*ICMP
*DIRECT
*CFG
*DFTROUTE *CFG
*DFTROUTE *CFG

F11=Display next hop
F18=Bottom

F12=Cancel

Bottom

Figure 49. Display TCP/IP Route Information, Display 2 of 2

To view detailed information about a specific route, type 5 in the option field next to
the route and press the Enter key. See Figure 46 on page 68 and Figure 47 on
page 68.

Chapter 3. TCP/IP: Operation, Management, and Advanced Topics

Displaying TCP/IP Connections
You can request more detailed information about TCP/IP connections shown on the
Work with TCP/IP Connection Status display. This information includes timing
information and transmission statistics for the connection displayed.
To display more information about the listed TCP/IP connections:
1. Type 5 in the option field for each connection about which you want more
information.
2. Press the Enter key.
A series of up to three displays for each connection appears. Press the Page Down
key to view the remaining displays.
The contents of the displays vary depending on the type of connection, whether
*TCP, *UDP, or *IPS. (Figure 50,Figure 51 on page 71, and Figure 52 on page 71
show displays for a TCP connection.)
Display TCP Connection Status
Connection identification:
Remote host name . . . . . . . . . .
Remote internet address . . . . . .
Remote port . . . . . . . . . . . .
Local host name . . . . . . . . . . .
Local internet address . . . . . .
Local port . . . . . . . . . . . .
Associated user profile . . . . . . .
TCP programming interface information:
State . . . . . . . . . . . . . . . .
Connection open type . . . . . . . .
Timing information:
Idle time . . . . . . . . . . . . . .
Last activity date/time . . . . . .
Round-trip time . . . . . . . . . . .
Round-trip variance . . . . . . . . .
Press Enter to continue.
F3=Exit
F5=Refresh
F14=Display port numbers

.
.
.
.
.
.
.

:
:
:
:
:
:
:

OS/400 TCP/IP Configuration and Reference V4R4

SYSNAM04

drfun.rchland.ibm.com
9.5.15.134
1025
sysnam04.endicott.ibm. >
9.125.87.143
telnet
QTCP

. . . . :
. . . . :

Established
Passive

.
.
.
.

000:00:00.381
05/25/94 14:38:11
.133
.016

.
.
.
.

:
:
:
:

More...
F6=Print
F10=Display IP options
F22=Display entire field

Figure 50. Display TCP/IP Connection Status, Display 1 of 3

System:

F12=Cancel

Display TCP Connection Status
Bytes out . . . . . . . .
Outgoing bytes buffered
User send next . . . .
Send next . . . . . . .
Send unacknowledged . .
Outgoing push number .
Outgoing urgency number
Outgoing window number
Bytes in . . . . . . . .
Incoming bytes buffered
Receive next . . . . .
User receive next . . .
Incoming push number .
Incoming urgency number
Incoming window number

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

:
:
:
:
:
:
:
:
:
:
:
:
:
:
:

System:
57692
0
3270868150
3270868150
3270868150
3270868149
3270868149
3270896558
1021
0
1545153023
1545153023
1545153023
1545153022
1545160742

SYSNAM04

More...

Press Enter to continue.
F3=Exit
F5=Refresh
F14=Display port numbers

F6=Print
F10=Display IP options
F22=Display entire field

F12=Cancel

Figure 51. Display TCP/IP Connection Status, Display 2 of 3

Display TCP Connection Status
Retransmission information:
Total retransmissions . . . . .
Current retransmissions . . . .
Send window information:
Maximum size . . . . . . . . .
Current size . . . . . . . . .
Last update . . . . . . . . . .
Last update acknowledged . . .
Congestion window . . . . . . .
Slow start threshold . . . . .
Precedence and security:
Precedence . . . . . . . . . .
Initialization information:
Maximum segment size . . . . .
Initial send sequence number .
Initial receive sequence number
Press Enter to continue.
F3=Exit
F5=Refresh
F14=Display port numbers

System:

. . . . . . . :
. . . . . . . :

8
0

.
.
.
.
.
.

28672
28408
1545153004
3270868150
2704
1281

.
.
.
.
.
.

:
:
:
:
:
:

. . . . . . . :

. . . . . . . :
. . . . . . . :
. . . . . . . :

536
3270810457
1545152001

SYSNAM04

Bottom
F6=Print
F10=Display IP options
F22=Display entire field

F12=Cancel

Figure 52. Display TCP/IP Connection Status, Display 3 of 3

Displaying Connection Totals
To display a summary of TCP and UDP counts, press F10 on the Work with TCP/IP
Connection Status display. The counts provided are a cumulative summary of all
TCP and UDP activity since the last time the STRTCP (Start TCP) command was
issued.

Chapter 3. TCP/IP: Operation, Management, and Advanced Topics

The information in Figure 53 and Figure 54 shows TCP and UDP counts that are
maintained for Simple Network Management Protocol (SNMP). For additional
information about SNMP, see the Simple Network Management Protocol (SNMP)
Support book.
Display TCP/IP Connection Totals
TCP connection information:
Currently established . . .
Active opens . . . . . . .
Passive opens . . . . . . .
Attempted opens that failed
Established and then reset

.
.
.
.
.

:
:
:
:
:

System:

1
0
0
0
0

TCP send information:
Segments sent . . . . . . . . . . . . . . . :
Retransmitted segments . . . . . . . . . . :
Reset segments . . . . . . . . . . . . . . :

108
10
0

TCP receive information:
Segments received . . . . . . . . . . . . . :
Segments received in error . . . . . . . . :

117
0
More...

Press Enter to continue.
F3=Exit

F5=Refresh

SYSNAM04

F6=Print

F12=Cancel

Figure 53. Display TCP/IP Connection Totals, Display 1 of 2

Display TCP/IP Connection Totals
UDP send information:
Datagrams sent . . . . . . . . . . . . . . :
UDP receive information:
Datagrams received . . . . .
Datagrams not delivered . . .
Application port not found
Other datagrams in error .

.
.
.
.

:
:
:
:

System:

SYSNAM04

0
0
0

0
0

Figure 54. Display TCP/IP Connection Totals, Display 2 of 2

TCP/IP Host Tables
Host tables are a method for mapping host names to IP addresses. This is done by
using a hosts file for name-to-address resolution. Because the host table lacks the
structure to list names in any hierarchical order, names assigned to hosts must be
unique. In the topics that follow, you will find discussions about the overall
management of TCP/IP host tables. Instructions for merging host tables and
managing a host table from a central site are included.
Successful TCP/IP host table maintenance also includes periodically evaluating
whether or not to use a DNS server to manage your network. The DNS server is
often the preferred alternative to host tables for the purpose of managing IP
addresses and host names, particularly in large network environments. However,

OS/400 TCP/IP Configuration and Reference V4R4

even some small organizations that access the Internet require a DNS server to
meet their name-service needs. See “Chapter 18. AS/400 Domain Name System
(DNS)” on page 421 for more information.

Managing TCP/IP Host Tables
In a large network, it can be more efficient to administer AS/400 TCP/IP from a
central site. Working with the host table would be time consuming if each system is
individually updated with the TCP/IP configuration menu. Updates can be made
more quickly on one system and then copied to others.
AS/400 TCP/IP is designed to protect configuration files, including the host table.
You cannot change the host table file unless you use the Configure TCP/IP menu or
the MRGTCPHT, ADDTCPHTE, RNMTCPHTE, CHGTCPHTE, or RMVTCPHTE
commands. However, you can still import and use a host table from a central site
by using the MRGTCPHT command.
The following host table file types can be imported and merged with the AS/400
host table:
v Host table type *AS400, generated by AS/400 TCP/IP Version 3 Release 1
Modification 0 (V3R1M0) or later
v Host table type *AIX, generated by AS/400 TCP/IP Version 3 Release 0
Modification .5 (V3R0M5), Version 2 Release 3 (V2R3) or earlier, or many other
IBM and non-IBM systems
v Host table type *NIC, host table format used by public domain systems
You can merge or replace the local AS/400 host table with the imported host table.
The name of the database file containing the local host table is QATOCHOST with
member HOSTS in library QUSRSYS. This file is used directly by AS/400 TCP/IP;
no conversion into an internal version takes place.

Host File Formats
If you receive a host file and want to use it on your system, the MRGTCPHT
(Merge TCP/IP Host Table) command allows you to specify which format you are
using. You can use host information files that are in either the *NIC format, the *AIX
format, or the *AS400 format. The record length of the imported host table file is not
limited.

Host Table Information with *AIX Files
Table 5 shows the *AIX format supported on the AS/400 system.
Table 5. *AIX Supported on the AS/400 System
Delimiter

Meaning

# (pound sign)

Indicates the beginning of a comment. The text following
the pound sign is a comment and is not part of the host
table.

blank, tab

Indicates a field delimiter.

Chapter 3. TCP/IP: Operation, Management, and Advanced Topics

Host Table Information with *NIC Files
The *NIC format is often used by hosts in the public domain. A record in a *NIC file
has the following format:
HOST : 128.12.19.1 : Host2.lan.ibm.com,Host2 : PC-AT : DOS : TCP/IP

This entry describes one host (at address 128.12.19.1) with two names
(Host2.lan.ibm.com) and (Host2). The host is an IBM Personal Computer AT
computer running MS-DOS and supporting TCP/IP.
A complete description of the *NIC format is found in Request for Comment (RFC)
952, Internet Host Table Specification. The subset supported on the AS/400 system
is shown in Table 6. The *NIC continuation characters are not supported because
the record length of the file can be up to 512 bytes.
Table 6. *NIC Subset Supported on the AS400 System
Delimiter

Meaning
1

; (semicolon)

Indicates the beginning of a comment. The text following
the semicolon is a comment and is not part of the host
table.

NET2

A keyword introducing a network entry.

GATEWAY

A keyword introducing a gateway entry.

HOST

A keyword introducing a host entry.

: (colon)

A field delimiter.

:: (two colons)

Indicates a null field.

, (comma)

A data element delimiter.

Notes:
1. If any line in the *NIC table contains a semicolon as the first column value, then that line
is not merged into the AS/400 host table.
2. These entries are not merged into the AS/400 host table.

Host Table Information with *AS400 Files
The *AS400 file format is the format of the local AS/400 host table file used by
AS/400 TCP/IP directly. The name of the file is QATOCHOST with member HOSTS
in library QUSRSYS. A single record contains an Internet address, up to four
host/domain names and a text description field. For more details regarding record
and file formats, use the DSPFFD (Display File Field Description) command.
This file can be exchanged between AS/400 systems. However, there is no function
to convert from *AS400 to *AIX or *NIC format.

Tips for Merging Host Tables
A maximum of four host names per IP address is allowed when host tables are
merged. For example, if the local host table already has three host names and the
physical file member to be merged has two additional host names, only the first
host name in the physical file is merged into the final host table.
Host names that exist for the same Internet address are not duplicated. If the same
host name is found for Internet addresses that are different, then that host name is
accepted, but a warning message is displayed.

OS/400 TCP/IP Configuration and Reference V4R4

The original copy of the local host table is not saved by the MRGTCPHT (Merge
TCP/IP Host Table) command. To save the original host table, create a copy of the
file QUSRSYS/QATOCHOST.HOSTS by using the Copy File (CPYF) command. Do
this before issuing the MRGTCPHT command.

Merging TCP/IP Host Tables
You can use imported host tables in two ways:
v Overwrite the current host table. To do this, specify Replace Host Table (*Yes)
on the Merge Host Table display.
v Merge the information of the imported host table with the information that was
entered by using option 10 (Work with TCP/IP host table entries) from the
Configure TCP/IP menu. To merge the information, specify Replace Host Table
(*No) on the Merge Host Table display.
You can merge an imported host table with the local host table while TCP/IP is
running by using the CFGTCP (Configure TCP/IP) command. The changes take
affect the next time a TCP/IP application accesses the host table.
Select option 11 to merge an imported host table with the local AS/400 host table.
You can also use the Merge TCP/IP Host Table (MRGTCPHT) command from any
command line.

Example: Successful Host Table Merge
The following example shows the command to merge an imported host table with
the local host table.
MRGTCPHT FROMFILE(QUSRSYS/M02HOSTS) FILEFMT(*AS400) REPLACE(*NO)
File M02HOSTS, member *FIRST, successfully merged with host
table.

Example: Partly Successful Host Table Merge
The following example shows the command to merge an imported host table with
the local host table.
MRGTCPHT FROMFILE(QUSRSYS/M03HOSTS) FILEFMT(*AS400) REPLACE(*NO)
Duplicate host name SPARKY.SYSNAM123.IBM.COM at address 9.4.6.138
found host table.
Duplicate host name MVAX.SYSNAM123.IBM.COM at address 9.4.6.252
found host table.
File M03HOSTS, member *FIRST, merged with host table: however,
error occurred.

In this example, the host table contains entries with the same host name, which
shows in the message as duplicate host names.

Managing the Host Table from a Central Site
If your network has multiple AS/400 systems, you can define the TCP/IP host table
on one system and share that table with the other systems. This saves you the
effort of having to define the host table on each system. To do this, follow these
steps:

Chapter 3. TCP/IP: Operation, Management, and Advanced Topics

Step 1—Create the Host Table on Your Central System
Use the CFGTCP command to configure your host table. Select option 10 (Work
with TCP/IP host table entries). Your system’s host table is stored in member
HOSTS of file QATOCHOST in library QUSRSYS.

Step 2—Start FTP to a Remote System
For example, if your host table defines the remote system as SYSNAM02, type the
FTP command as follows:
ftp sysnam02

Step 3—Tell FTP to Send the Host File to the Remote System
Type the following FTP subcommand:
put qusrsys/qatochost.hosts qusrsys/m03host.hosts

Note: Do not use FTP to put the host file directly into file QATOCHOST containing
the AS/400 host table.

Step 4—Merge the File
Type the following FTP subcommand:
quote rcmd mrgtcpht fromfile(qusrsys/m03host) frommbr(host)

Domain Name System (DNS) Server
The conversion from host name to Internet address can be performed by using the
host table on the local system or by defining a Domain Name System server, or
DNS server.
In large networks with large host tables, it is more convenient to have DNS servers
than to have a complete copy of the host table on every host in the network. As a
single source for host names, a DNS server is capable of storing the name and
address translations for all of the computers on your network. The DNS server is
the preferred alternative to managing host tables.
This chapter does not document DNS server functions. However, if you are
interested in more detailed information about Domain Name System server (DNS)
support on your AS/400 and configuring a DNS server see “Chapter 18. AS/400
Domain Name System (DNS)” on page 421.

IP Routing and Internet Control Message Protocol (ICMP) Redirecting
Internet routing tables usually remain static for long periods. TCP/IP generates
routing tables at activation time from configuration data and adjusts the routing
tables based on ICMP redirects, SNMP manager requests, dead gateway
processing and socket routing requests.
If network interconnections change, routing tables in a particular host may become
incorrect. Because gateways exchange routing information periodically to
accommodate network changes and to keep their routes up to date, a gateway
usually knows better routes than a host. When a gateway detects that a host is
using a route that is not optimum, the gateway sends an ICMP redirect message to

OS/400 TCP/IP Configuration and Reference V4R4

that host. It also forwards the original datagram on to its destination. Redirect
messages are limited to interactions between a gateway and a host on the same
network.
If the host that sends the original datagram is an AS/400, it receives the ICMP
redirect message from the gateway and uses this information to update its internal
routing table. The next datagram is then sent using the more optimum route
received from the gateway. You can see the updated routing table by using
NETSTAT, option 2. A route created by the ICMP redirect mechanism is recorded in
the IP dynamic routing table and remains there as long as an upper level protocol is
using it. When the last upper-level protocol user has completed its unit of work
using a route created by the ICMP redirect mechanism, the route is then removed
from the routing table. When TCP/IP is restarted, this process is repeated.
In Figure 55, host A1 in network 2 is an AS/400 system that sends a message to
host A2 in network 3. The routing table in host A1 indicates that the first hop to host
A2 is through gateway G1, which connects networks 1 and 2. When this gateway
receives the datagram, it forwards the datagram to gateway G2, which sends it to
the host A2. Gateway G1 then sends an ICMP redirect message to host A1 to
inform it that a better route to host A2 is to use gateway G2 as the first hop. This
information updates the internal routing table in host A1, and the next datagram to
host A2 in network 3 is sent to gateway G2 as the first hop. The gateway then
sends the datagram to host A2. When the TCP/IP services are stopped, the
collected routing information is deleted and host A1 starts the learning process
again.

Figure 55. Example of ICMP Redirect

To see routing changes due to ICMP redirect messages, select NETSTAT menu 2
or NETSTAT *RTE and then press PF11. Comparing the next hop in this display
with the next hop present in the routing table, you can verify whether a route has
been dynamically changed.

Chapter 3. TCP/IP: Operation, Management, and Advanced Topics

Dead Gateway Processing
RFC-1122, Requirements For Internet Hosts - Communication Layers, requires the
IP layer to include a dead gateway algorithm to manage suspected gateway
failures. This section is intended to give you an overview of dead gateway
processing.
Two types of gateway failures can occur:
v Failure of a first-hop gateway. A first-hop gateway is the gateway that is specified
in an IP route. First-hop gateways must be on a directly-connected network. This
type of failure can be detected by either TCP or the data link layer.
v Failure of a gateway other than the first-hop gateway. The path between source
and destination TCP/IP hosts can traverse multiple gateways. This type of failure
can be detected only by TCP.
Dead gateway processing is initiated when IP receives a negative advice indicator
from either TCP or the data link layer. These indicators from TCP and the data link
layer are referred to as advice since they may result from transient conditions as
well as from a serious gateway failure.

Negative Advice from TCP or the Data Link Layer
Retransmissions on a TCP connection occur as a result of transient or non-transient
problems somewhere along the path to a destination host. When TCP notices
excessive retransmissions on a TCP connection, a TCP negative advice indicator is
sent to IP.
The data link layer passes a negative advice indicator to IP when it is unable to
transmit data to a first-hop (directly-connected) gateway. In most cases, negative
advice from the data link layer means that the Address Resolution Process (ARP)
processing performed by the data link layer was unable to resolve the location of
first-hop gateway on the directly connected physical network. (ARP is not performed
on all physical network types. Some physical network types, such as X.25, use an
alternative scheme for this purpose.)
Negative advice, whether from TCP or the data link layer, is always expressed in
terms of the first-hop gateway. Dead gateway processing on a given host only
attempts to verify the first-hop gateway. However, gateways also carry out their own
dead gateway processing for other adjacent gateways. In this way, all of the
gateways along the path to a destination host are taken care of.

How IP Responds to Negative Advice
When receiving negative advice from TCP or the data link layer concerning a next
hop gateway, IP marks all routes that use this gateway as suspect. IP attempts to
deliver data destined for the suspect gateway via routes that use other gateways (if
any are configured). Next, an IP process is started that uses periodic PING
requests to attempt to contact the suspect next-hop gateway. If the suspect
gateway continues to be unresponsive for an extended period of time, the
frequency of the PING requests is reduced.
When any PING response is received from a suspect gateway, the gateway is
considered active and the routes are restored.

OS/400 TCP/IP Configuration and Reference V4R4

Notes about IP Responses to Negative Advice:
1. If an ICMP redirect message is received during dead gateway processing,
routes to a suspect gateway may be temporarily restored. However, dead
gateway PING processing is not interrupted, and subsequent negative advice
forces the IP routing table back to its previously adjusted state.
2. Responses from user-initiated PINGs can also indicate that a suspect gateway
is active.
3. Negative advice is not passed from the UDP or RAW IP protocol machines.
Applications using these protocols must use other mechanisms to detect and
respond to apparent network problems. However, data link layer-negative advice
is still used to manage problems with the first-hop gateway.

Multihoming Function
A multihomed host has multiple IP addresses, which we may think of as logical
interfaces. These logical interfaces may be associated with one or more physical
interfaces, and these physical interfaces may be connected to the same or different
networks.
The AS/400 TCP/IP implementation supports multihoming. This allows you to
specify either a single interface or multiple interfaces for a line description. You can
have your AS/400 appear as any one or combination of the following scenarios:
v A single host on a network over a communications line
v Multiple hosts on the same network over the same communications line
v Multiple hosts on the same network over multiple communications lines
v Multiple hosts on different networks over the same communications line
v Multiple hosts on different networks over multiple communications lines
Note: The maximum number of interfaces that can be active on a line description
at any given time is 128. This is true for all line types (for example,
token-ring, Ethernet, frame relay, and so forth).

Example: A Single Host on a Network over a Communications Line
Your AS/400 system uses one adapter for TCP/IP to attach to a LAN or WAN
network. You add one TCP/IP interface. This TCP/IP interface includes the Internet
address of your AS/400 system. With this single Internet address, your AS/400
system is part of a single TCP/IP network (Figure 56).

Figure 56. Multihoming - Single Host, Single Network, Single Line

Chapter 3. TCP/IP: Operation, Management, and Advanced Topics

Example: Multiple Hosts on the Same Network over the Same
Communications Line
Your AS/400 system uses one adapter for TCP/IP to attach to a LAN or WAN
network. You add multiple TCP/IP interfaces. Each of these TCP/IP interfaces
includes an Internet address of the same TCP/IP network. With these multiple
Internet addresses your AS/400 system appears as multiple hosts in a single
TCP/IP network (Figure 57).
This can be a migration scenario.

Figure 57. Multihoming - Multiple Hosts, Single Network, Single Line

Example: Multiple Hosts on the Same Network over Multiple
Communications Lines
Your AS/400 system uses more than one adapter for TCP/IP to attach to the same
LAN or WAN network. You add multiple TCP/IP interfaces. At least one interface is
assigned to each adapter/line description. Each of these TCP/IP interfaces includes
an Internet address of the same TCP/IP networks. With these multiple Internet
addresses, your AS/400 system appears as multiple TCP/IP hosts in the same
TCP/IP network (Figure 58).

Figure 58. Multihoming - Multiple Hosts, Single Network, Multiple Lines

This scenario can be helpful for backup or to improve performance. However, there
is no dynamic backup or performance balance function.

OS/400 TCP/IP Configuration and Reference V4R4

Example: Multiple Hosts on Different Networks over the Same
Communications Line
Your AS/400 system uses one adapter for TCP/IP to attach to a LAN or WAN
network. You add multiple TCP/IP interfaces. Each of these TCP/IP interfaces
includes an Internet address of different TCP/IP networks. With these multiple
Internet addresses, you participate in different TCP/IP networks (Figure 59).

Figure 59. Multihoming - Multiple Hosts, Multiple Networks, Single Line

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Imagine a public X.25 network. With this physical network, you can run multiple
different TCP/IP networks, for example the company intranet, and connections with
business partners and service providers. For each of these different TCP/IP
networks, your AS/400 system must configure a unique Internet address.
Running multiple TCP/IP networks within a single local area network (LAN) is also
supported. In most situations, however, one designs a single TCP/IP network per
physical LAN only.

Example: Multiple Hosts on Different Networks over Multiple
Communications Lines
Your AS/400 system uses more than one adapter for TCP/IP to attach to multiple
LAN or WAN networks. You add multiple TCP/IP interfaces. At least one interface is
assigned to each adapter/line description. Each of these TCP/IP interfaces includes
an Internet address of different TCP/IP networks. With these multiple Internet
addresses, you take part in different TCP/IP networks (Figure 60 on page 82).
This example is a combination of all of the previous examples discussed.

Chapter 3. TCP/IP: Operation, Management, and Advanced Topics

Figure 60. Multihoming - Multiple Hosts, Multiple Networks, Multiple Lines

Example: The Multihoming function
Assume AS/400 systems SYSNAM02 and SYSNAM03 are connected with a public
or private X.25 network. The Internet address of this network is 9.4.73.64.
In this example, the AS/400 system SYSNAM03 connects with a service provider by
using TCP/IP and the same X.25 network attachment (Figure 61). The Internet
address assigned by the service provider for the AS/400 system is 223.1.1.17.

Figure 61. Multihoming TCP/IP Network

The multihoming function supports multiple networks with the same adapter. AS/400
system SYSNAM03 must handle two different Internet addresses on the same
attachment. To do this, an additional TCP/IP interface needed to be specified
(Figure 62 on page 83).

OS/400 TCP/IP Configuration and Reference V4R4

Work with TCP/IP Interfaces
Type options, press Enter.
1=Add
2=Change
4=Remove
Opt
__
__
__
__

5=Display

Internet
Subnet
Address
Mask
_______________
9.4.73.65
255.255.255.192
127.0.0.1
255.0.0.0
223.1.1.17
255.255.255.0

F3=Exit
F12=Cancel

F5=Refresh
F17=Top

F6=Print list
F18=Bottom

9=Start

System:

SYSNAM03

10=End

Line
Description

Line
Type

X25LINE
*LOOPBACK
X25LINE

*X25
*NONE
*X25

F11=Display interface status

Figure 62. Work with TCP/IP Interfaces Display, Multihoming

Type of Service (TOS)
Type of Service (TOS) is a parameter defined to indicate a quality of the service
desired by an application program. It is specified within a single octet of the IP
datagram header, and it is used to select Internet service. It denotes how the
Internet hosts and routers should make trade-offs between throughput, delay,
reliability, and cost.
TOS is used to identify and select the actual transmission characteristics for a
particular network, the interface, and the route to be used when routing an Internet
datagram. The TOS values are mapped into the actual TOS value of the particular
network a datagram is going through. All of the values are mutually exclusive.
The TOS values are defined through the Add TCP/IP Interface (ADDTCPIFC) and
Add TCP/IP Route (ADDTCPRTE) commands. The possible selections are as
follows:
*NORMAL
Normal service is used for delivery of datagrams.
*MINDELAY
Minimize delay means that prompt delivery is important for datagrams with this
indication.
*MAXTHRPUT
Maximize throughput means that high data rate is important for datagrams with
this indication.
*MAXRLB
Maximize reliability means that a higher level of effort to ensure delivery is
important for datagrams with this indication.
*MINCOST
Minimize monetary cost means that lower cost is important for datagrams with
this indication.
Chapter 3. TCP/IP: Operation, Management, and Advanced Topics

The following table shows which type of services AS/400 uses for some of the
TCP/IP applications:
Table 7. AS/400 TCP/IP applications and Type of Services
Protocol or Application

Type of Service Used

TELNET

Normal

FTP (control connection)

Minimize delay

FTP (data connection)

Maximize throughput

SMTP (command phase)

Minimize delay

SMTP (data phase)

Maximize throughput

POP (all phases)

Maximize throughput

SNMP

Maximize reliability

Thus, TOS is a suggestion, not a demand, to the interface (if more than one is
present in the system) and to the routing algorithms. If a TCP/IP subsystem knows
more than one interface and more than one possible route to a given destination, it
uses the TOS to select one with characteristics closest to that desired.

TOS Example
For example, suppose the system can select between a low-capacity nonswitched
line or a high-bandwidth (but high delay) satellite connection:
v Datagrams carrying keystrokes from a user to a remote computer could have the
type of service set to *MINDELAY, requesting that they be delivered as quickly as
possible.
v Datagrams carrying a bulk file transfer could have the type of service set to
*MAXTHRPUT, requesting that they travel across the high-capacity satellite path.
It is up to the network administrator to define TOS values when defining interfaces
and routes in the TCP/IP configuration. Based on the administrator’s knowledge of
the hardware technologies available on systems and networks used, TOS values for
the routes must also be defined according to the interface’s TOS value. This means
that if a *MINDELAY value is defined in the interface definition, at least one route
definition must have the *MINDELAY TOS value defined.
Note: A TCP/IP network does not guarantee the TOS requested. However,
datagram transmission is never denied.

Multiple Routes
You can have multiple routes in your routing table (by using the ADDTCPRTE
command). You can have more than one route for the same destination Internet
address with the same type of service or a different type of service. If you have
multiple routes with the same types of service, they are used in the order specified.
If a particular next hop router is not available, the subsequent specified next hop
router is used. This continues until an entry that is active is found or the list of next
hop values is exhausted. If you have multiple routes with different TOS, the one
with the TOS equal to the one requested by applications with TOS octet in IP
datagram is used. If no match is found in any specified routes, the route with the
closest TOS or *NORMAL TOS is used.
You can have *DFTROUTE, and specific route destination addresses. Default
routes are used only when data is sent to a remote destination system that does

OS/400 TCP/IP Configuration and Reference V4R4

not have a specific route defined. The system allows up to eight default routes, but
each route must have a unique next hop value.
An example of a multiple route table can be found in Figure 63.
Work with TCP/IP Routes
Type options, press Enter.
1=Add
2=Change
4=Remove

Opt
_
_
_
_
_
_
_

Route
Destination
______________
*DFTROUTE
*DFTROUTE
*DFTROUTE
9.4.70.0
9.4.70.0
9.4.70.0

System:

SYSNAM003

5=Display

Subnet
Mask
______________
*NONE
*NONE
*NONE
255.255.255.0
255.255.255.0
255.255.255.0

Next
Hop
______________
9.4.73.193
9.4.73.197
9.4.73.196
9.4.73.194
9.4.73.195
9.4.73.198

F3=Exit
F5=Refresh
F6=Print list
F11= Display type of service F12=Cancel

Preferred
Interface
*NONE
*NONE
*NONE
*NONE
*NONE
*NONE

Bottom
F10=Work with IP over SNA routes
F17=Top
F18=Bottom

Figure 63. Work with TCP/IP Routes Display

TCP/IP Port Restriction
TCP and UDP protocols use ports to identify a unique origin or destination of
communication with an application. Each port is assigned a small integer. You can
configure port information if you want to restrict the use of a TCP or UDP port to
one or more user IDs.
The range of port numbers is from 1 to 65535. However, ports 0-1023 are reserved
as well-known port numbers, which are controlled and assigned by the Internet
Assigned Numbers Authority (IANA). Only those applications that have been
assigned one of these ports should use a number within this range. Refer to the
current Assigned Numbers RFC for a list of the port assignments.
Because this range of port numbers, 0-1023, is reserved for the well-known ports,
they should not be used by user application programs because it could affect the
operation of TCP/IP. For example, restricting the use of ports 21, 23, or 25,
prevents other users from using FTP, TELNET, or SMTP, respectively.
The AS/400 Add TCP/IP Port Restriction (ADDTCPPORT) command allows you to
restrict usage of a single port or a range of ports to a particular AS/400 user profile.
Restricting ports is like allocating ports to a specific user profile. When a socket
application issues the bind() system call, or when a TCP/UDP Pascal API
application issues a call to the TcpOpen, TcpWaitOpen, or UdpOpen function, the
job’s user profile is checked against the list of user profiles that are associated with

Chapter 3. TCP/IP: Operation, Management, and Advanced Topics

the specified port. If no match is found, the requesting program is not allowed to
use the specified port. If any port in the 1-1023 range is restricted, the following
message is posted:
Port restriction added but may affect TCP/IP processing

If no user profiles are associated with a specific port, there are no restrictions.
It is not necessary to configure port restrictions unless you are writing your own
TCP/IP applications and you want to reserve the use of the applications to certain
user profiles.
Note: For an installation in which user-written programs use ports other than the
well-known ports, you can consider restricting the use of the well-known
ports to the user profiles running the server application. As an example, for
File Transfer Protocol (FTP), this would be user profile QTCP.

Configuring TCP/IP Port Restrictions
To configure TCP/IP port restrictions, type option 4 on the Configure TCP/IP menu.
The Work with TCP/IP Port Restrictions display is shown (Figure 64).
Work with TCP/IP Port Restrictions
Type options, press Enter.
1=Add
4=Remove
Opt
_

F3=Exit

--Port Range--Lower
Upper
_____
*ONLY
1050
1059

F5=Refresh

Protocol
____
*TCP

F6=Print list

System:

SYSNAM03

User
Profile
__________
PAOLO

F12=Cancel

F17=Top

F18=Bottom

Bottom

Figure 64. Work with TCP/IP Port Restrictions Display

Type option 1 (Add) at the input-capable top list entry to get to the Add TCP/IP Port
Entry (ADDTCPPORT) display shown in Figure 65 on page 87. You can go directly
to this display by typing ADDTCPPORT on any command line and pressing F4.

OS/400 TCP/IP Configuration and Reference V4R4

Add TCP/IP Port Restriction (ADDTCPPORT)
Type choices, press Enter.
Range of port values:
Lower value . . . .
Upper value . . . .
Protocol . . . . . . .
User profile . . . . .

F3=Exit
F4=Prompt
F24=More keys

.
.
.
.

. 1060
. > *ONLY
. *tcp
. gerry

F5=Refresh

1-65535
1-65535, *ONLY
*UDP, *TCP
Character value

F12=Cancel

Bottom
F13=How to use this display

Figure 65. Add TCP/IP Port Restriction Display

Let us assume we have an application that uses Port 1060 in the TCP layer and we
want to restrict its use to user profile GERRY. Type the information as shown in
Figure 65.
Figure 66 shows what the display looks like after you enter port information for both
user profiles PAOLO and GERRY.
Changes to the port restrictions take effect immediately. However, applications that
are already active are not affected until they are restarted.
Work with TCP/IP Port Restrictions
Type options, press Enter.
1=Add
4=Remove
Opt
_

F3=Exit

--Port Range--Lower
Upper
_____
*ONLY
1050
1059
1060
*ONLY

F5=Refresh

Protocol
____
*TCP
*TCP

F6=Print list

System:

SYSNAM03

User
Profile
__________
PAOLO
GERRY

F12=Cancel

F17=Top

F18=Bottom

Bottom

Figure 66. Work with TCP/IP Port Restrictions Display

Chapter 3. TCP/IP: Operation, Management, and Advanced Topics

Related Tables and the Host Table
Socket applications require a set of tables from which they can retrieve specific
TCP/IP network data when needed. These are as follows:
v Host table
v Service table
v Protocol table
v Network table
The host table contains a list of host names and corresponding Internet addresses.
Socket applications requesting host data obtain it either from the AS/400 host
database file or from the domain name server.
The service table contains a list of services and the specific port and protocol a
services uses. The protocol table contains a list of protocols used in the TCP/IP
network. The network table contains a list of networks and the corresponding
Internet addresses.
UNIX** systems traditionally store this information in the following files:
v
v
v
v

/etc/hosts - host table
/etc/protocols - protocol table
/etc/services - service table
/etc/networks - network table

AS/400 TCP/IP maintains the service, protocol, and network tables as database
files. AS/400 TCP/IP refers to these three tables as related tables. To configure or
view the protocol, services, or network tables, select option 21 (Configure Related
Tables) on the Configure TCP/IP menu. You are shown the display in Figure 67 .
Configure Related Tables
Select one of the following:

System:

SYSNAM03

1. Work with service table entry
2. Work with protocol table entry
3. Work with network table entry

Selection or command
===> ___________________________________________________________________
________________________________________________________________________
F3=Exit
F4=Prompt
F9=Retrieve
F12=Cancel

Figure 67. Configure Related Tables Menu

OS/400 TCP/IP Configuration and Reference V4R4

You can change the services, protocols, and network files using the options from
this display.
The services table stores the mapping of services to ports or ports to services as
shown in Figure 68. The mapping information is usually accessed with the
getservbyname() and getservbyport() socket functions.
Work with Service Table Entry

System:

Type options, press Enter.
1=Add
4=Remove
5=Display
Opt

Service
echo
finger
finger
ftp-control
ftp-control
ftp-data
ftp-data
gopher
gopher
graphics
graphics
pop3

Port
7
79
79
21
21
20
20
70
70
41
41
110

Parameters for options 1 and 4 or command
===>
F3=Exit
F4=Prompt
F5=Refresh
F6=Print list
F17=Top
F18=Bottom

SYSNAM03

Protocol
udp
tcp
udp
tcp
udp
tcp
udp
tcp
udp
tcp
udp
tcp

F9=Retrieve

More...
F12=Can

Figure 68. Work with Service Table Entry Display

The protocol table stores the mapping of protocol names to protocol numbers and
protocol numbers to protocol names. Socket applications use getprotobyname() and
getprotobynumber() functions to access this table (Figure 69 on page 90).

Chapter 3. TCP/IP: Operation, Management, and Advanced Topics

Work with Protocol Table Entry

System:

Type options, press Enter.
1=Add
4=Remove
5=Display
Opt
_
_
_
_
_

Protocol
_____________________________
icmp
ip
tcp
udp

SYSNAM03

Protocol
number
1
0
6
17

Bottom
Parameters for options 1 and 4 or command
===> ______________________________________________________________________
F3=Exit
F4=Prompt
F5=Refresh
F6=Print list
F9=Retrieve
F12=Cancel
F17=Top
F18=Bottom

Figure 69. Work with Protocol Table Entry Display

The network table contains the networks and the Internet address associated with
the network. Socket applications use the getnetbyname() and getnetbyaddr()
functions to access the information in the network table (Figure 70).
Work with Network Table Entry
Type options, press Enter.
1=Add
4=Remove
5=Display
Opt
_
_

Network
_____________________________________
IBM

System:

SYSNAM03

Internet
address
_______________
9.0.0.0

Figure 70. Work with Network Table Entry Display

The protocols and services tables that are shipped contain standard information.
The network tables do not contain any information. The network IBM information
has been added in Figure 70, as an example.

OS/400 TCP/IP Configuration and Reference V4R4

For additional information about sockets, refer to the Sockets Programming,
SC41-5422-03 book.

Using X.25 PVC instead of SVC
In “Step 5—Configuring TCP/IP Remote System Information (X.25)” on page 36 you
were shown how to define the X.25 network address of each system that uses a
switched virtual circuit (SVC).
To replace the X.25 SVC with an X.25 permanent virtual circuit (PVC) connection,
the example below is helpful. The following CL commands will look different:
CRTLINX25, ADDTCPIFC, and ADDTCPRSI.
Use the same X.25 line description, but replace the first of the four SVCs with a
PVC.
CRTLINX25 LIND(X25LINE) RSRCNAME(LIN051)
LGLCHLE((001 *PVC) (002 *SVCBOTH)
(003 *SVCBOTH) (004 *SVCBOTH))
NETADR(40030003) CNNINIT(*LOCAL)
TEXT('ITSO X.25 Network')

The TCP/IP interface now points to a specific PVC instead of a pool of SVCs.
ADDTCPIFC INTNETADR('9.4.73.65') LIND(X25LINE)
SUBNETMASK('255.255.255.192') PVCLGLCHLI(001)
MAXSVC(0)

The TCP/IP remote system information no longer includes the X.25 address to be
called. Instead, the entry points to the PVC channel ID.
ADDTCPRSI INTNETADR('9.4.73.66')
PVCLGLCHLI(001)

IP Multicasting
IP multicasting is the process of transmitting an IP datagram to a host group. The
hosts that are in the group may reside on a single subnet or on different subnets
that are connected by multicast-capable routers. Hosts may join and leave groups
at any time. There are no restrictions on the location or number of members in a
host group. For more information about IP multicasting, refer to RFC 1112, Host
Extensions for IP Multicasting.
Note: The AS/400 cannot act as a multicast-capable router.

Multicast Application Programming Information
An application program can send or receive multicast datagrams by using the
Sockets API and connectionless, SOCK_DGRAM type sockets. Multicasting is a
one-to-many transmission method. You cannot use connection-oriented sockets of
type SOCK_STREAM for multicasting. When a socket of type SOCK_DGRAM is
created, an application can use the setsockopt() function to control the multicast
characteristics associated with that socket. The setsockopt() function accepts the
following IPPROTO_IP level flags:
v IP_ADD_MEMBERSHIP: Joins the multicast group specified.

Chapter 3. TCP/IP: Operation, Management, and Advanced Topics

v IP_DROP_MEMBERSHIP: Leaves the multicast group specified.
v IP_MULTICAST_IF: Sets the interface over which outgoing multicast datagrams
should be sent.
v IP_MULTICAST_TTL: Sets the time to live (TTL) in the IP header for outgoing
multicast datagrams.
v IP_MULTICAST_LOOP: Specifies whether or not a copy of an outgoing multicast
datagram should be delivered to the sending host as long as it is a member of
the multicast group.
For additional information about sockets, including sample programs, see the
Sockets Programming, SC41-5422-03 book. The System API Reference,
SC41-5801-03 documents the sockets API.

Multicast Restrictions
Multicast does not map well to all types of physical lines. For this reason, it is not
supported on all lines. For example, a switched network such as X.25 does not lend
itself to multicast applications because no mechanism exists for transmitting a
single packet to all systems in the network that have joined a group. IP multicast is
supported on broadcast capable networks and on SLIP/PPP interfaces, but it is not
supported on multi-access nonbroadcast networks. IP multicast is also not currently
supported on Frame Relay, FDDI/SDDI, or ATM networks. To determine whether an
interface supports multicast, enter option 14 on the Work with TCP/IP Interface
Status display. If the interface supports multicast, there will be at least one Host
Group entry for the All Hosts group 224.0.0.1. Otherwise, the interface does not
support multicast.
The 2626 token-ring input-output processor (IOP) requires manual configuration to
receive multicast datagrams. In particular, you must specify the token-ring address,
C00000040000, on the functional address parameter for the token-ring line
description. To add this address to a line description that is named TRNLINE, use
the following command:
CHGLINTRN LIND(TRNLINE)

FCNADR(C00000040000)

The 2617 Ethernet IOP also requires manual configuration in order to receive
multicast datagrams. The Ethernet group addresses to be received need to be
specified on the group address parameter (GRPADR) for the Ethernet line
description. A 4-byte IP multicast address is mapped to a 6-byte Ethernet group
address by placing the low-order 23 bits of the IP multicast address into the
low-order 23 bits of the Ethernet group address 01005E000000. For example, to
receive multicast datagrams with a destination address of 224.255.0.2, the
GRPADR parameter for the 2617 Ethernet line description must include
01005E7F0002.

OS/400 TCP/IP Configuration and Reference V4R4

Chapter 4. Configuring Point-to-Point TCP/IP (PPP and SLIP)
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Important note: A thorough and in-depth explanation of Point-to-Point is beyond
the scope and purpose of this document. The majority of material on Point-to-Point
is covered in the AS/400e Information Center under the TCP/IP topic. For more
information see “TCP/IP Topics in the Information Center” on page xv.

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This chapter focuses on conceptual and reference information for the TCP/IP
Point-to-Point Protocol (PPP) and briefly describes its predecessor, the Serial Line
Internet Protocol (SLIP). This chapter does not document the procedures for AS/400
configuration and implementation of the PPP protocol. Those procedures are
covered in the AS/400e Information Center under the TCP/IP topic.

Networks and Point-to-Point Connections
When only two systems are physically connected, this is typically referred to as a
point-to-point connection or link. Several different protocols, such as PPP, SLIP,
X.25, and frame relay, can be viewed as point-to-point protocols. Support for
Point-to-Point (PPP) protocol is included in AS/400 as part of wide area network
(WAN) connectivity. A common example is a PPP connection that is established
periodically over a phone line from a remote office to a central office in order to
exchange data between the locations. This connection could be from a laptop
computer. Remote systems can access AS/400 applications such as Lotus Notes
over a PPP TCP/IP link. Figure 71 illustrates AS/400 responding to incoming calls.

Figure 71. Remote Systems Dial-in to an AS/400

Another common example of a PPP WAN connection is a dial-out connection that
your system establishes to an Internet Service Provider (ISP), such as the IBM
Global Network (IGN) (see Figure 72 on page 94.)

Figure 72. AS/400 Dial-out to an ISP

A wide area network (WAN) is usually distinguished from a local area network
(LAN) in that physical communications is limited to two systems. The
communications line between the two systems can be a direct connection such as a
leased telephone line. However, it is more common to connect two systems by a
dial-up telephone connection. A dial-up connection between systems is also known
as a switched connection. For a switched line, the connection turns on or off
depending on whether a phone connection has been established. In the case of a
leased line, the connection between the two systems is always available.

PPP versus SLIP
Serial Line Internet Protocol (SLIP) is the result of early attempts to connect two
systems using TCP/IP over an asynchronous line. SLIP is described in Request for
Comment (RFC) 1055, A Nonstandard For Transmission of IP Datagrams Over
Serial Lines: SLIP. This RFC defines a simple framing method for IP packets
flowing over a serial line. SLIP is not an Internet standard.
The SLIP RFC never became an Internet standard because it has several
deficiencies that are discussed in the RFC. Some of those deficiencies are as
follows:
v No standardized mechanism for hosts to communicate addressing information
v No support for network protocols other than TCP/IP
v No support for system authentication
v No support for packet error detection, error correction, or compression
While SLIP is still used today, IBM does not encourage you to use it. PPP corrects
all of the SLIP deficiencies. PPP is an Internet standard and the predominant
connection protocol used today among Internet Service Providers.

OS/400 TCP/IP Configuration and Reference V4R4

One goal of PPP is to allow interoperability among the remote access software of
different manufacturers. Another goal is to allow the same physical communication
line to be used by multiple network communication protocols.

Requirements for AS/400 SLIP
You need two or more computers that support the SLIP protocol. The following is a
summary of AS/400 requirements for Serial Line Internet Protocol (SLIP):
v The correct communications ports and adapters must be installed on AS/400.
v A connection must be established using either a switched line or a direct leased
line.
v A modem to send and receive data over the connection. “Connection
Alternatives” on page 111 contains a brief overview of data transmission
equipment available at the time of this writing.
v If you plan to connect to the Internet, you must have a dial-up account with an
Internet Service Provider (ISP).
Note: Many PCs have an internal modem that is equipped with the serial port.
AS/400 does not support an internal modem. You must use an external
modem connected to your AS/400 by one of the required I/O Adapters (IOA).

Point-to-Point Request for Comments (RFC)
A sample of related Request for Comments (RFC) are:
v RFC 1661, The Point-to-Point Protocol (PPP), describes the base structure for
PPP communications.
v RFC 1662, PPP in HDPC-like Framing, describes PPP packet encapsulation over
asynchronous and synchronous communication lines.
v RFC 1994, PPP Challenge Handshake Authentication Protocol (CHAP),
describes system authentication.

Line Pools
In the Point-to-Point Protocol (PPP), a line pool is a list of lines that are used by a
connection profile.
You can use a line pool instead of defining a particular line description to a
connection profile. The connection profile selects an available line from the line pool
when the profile is started.
Advantages of using line pools:
v You are not committing a line resource to a connection profile until it is started.
For connection profiles using a specific line, the connection profile ends if the line
is not available. For connection profiles that use a line pool, only one line in the
line pool must be available when the profile is started.
v You can use dial-on-demand profiles with line pools to use resources more
efficiently.
A line is selected from the line pool only when a dial-on-demand connection is
required. At other times, the same line can be used by other connection profiles.
v You can start more profiles than you have resource to support.

Chapter 4. Configuring Point-to-Point TCP/IP (PPP and SLIP)

Let us say your environment needs four dial-on-demand connection profiles, but
you only need two lines available at one time. You could create a line pool for
two of the four lines, so two connections profiles are active at any time. By using
a line pool, you do not need to have four lines available at the same time.

Configuring Point-to-Point Network Connections
This material is covered in the AS/400e Information Center under the TCP/IP
topic. For more information see “TCP/IP Topics in the Information Center” on
page xv.

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Configuring PPP Connection Profiles
This material is covered in the AS/400e Information Center under the TCP/IP
topic. For more information see “TCP/IP Topics in the Information Center” on
page xv.

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Accessing Point-to-Point functions through Operations Navigator
You can access Point-to-Point (PPP) functions from a command line interface or
Operations Navigator (graphical user interface). Not all PPP functions are available
on both interfaces, and most PPP functions are available only through Operations
Navigator. Operations Navigator functions are not documented here.
To access the Point-to-Point Profile Properties dialogs, perform the following
tasks:
1. Start Operations Navigator.
2. Double-click your AS/400 server in the main tree view of Operations Navigator.
3. Double-click Network.
4. Double-click Point-to-Point.
5. Right-click Connection Profiles to open a context menu.
6. Select New Profile to open the New Point-to-Point Profile Properties dialog.
Click the desired tab to define properties.

Checking for existing PPP Connection Profiles
This material is covered in the AS/400e Information Center under the TCP/IP
topic. For more information see “TCP/IP Topics in the Information Center” on
page xv.

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OS/400 TCP/IP Configuration and Reference V4R4

PPP Configuration Scenarios
Example: Configuring Windows 95/98 to an AS/400 using a PPP
Connection
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This material is covered in the AS/400e Information Center under the TCP/IP
topic. For more information see “TCP/IP Topics in the Information Center” on
page xv.

Example: Connecting to the Internet using an ISP
You can connect an AS/400 to the Internet by using an Internet Service Provider
(ISP). While there are many ISPs in service today, this example uses the IBM
Global Network (IGN) as a service provider. IGN requires an account, user ID, and
password. Other Internet Service Providers (ISP) may have different requirements.
The connection to the ISP is switched line-dial.
Access Point-to-Point functions through Operations Navigator.
From the General page, perform the following tasks:
v Specify DialIGN in the ″Name″ text box.
v Specify IGN (IGN-ISP) in the ″Description″ text box to describe the connection
profile in more detail.
v Select PPP under Type.
v Select Switched line-dial under Mode. This allows you to dial out to the remote
system.
Click the Connection tab.
v To specify the remote phone number for the IGN or another ISP, click Add and
specify the phone number.
If you need to dial a special number to reach an outside line, typically the outside
line number is followed by several commas. The commas determine how many
seconds the modem must wait for the dial tone before it begins dialing. You can
also use dashes in the phone number.
A remote phone number can be any of the following:
– Local company extension (for example, 34567)
– Outside phone number (for example, 9,1234567)
– Long distance number (for example, 1-800-1234567)
v In the ″Name″ field, select the appropriate line name, such as IGN_Dial.
If you need to configure a new line description, specify the name and click Open.
For more information, see “Configuring Point-to-Point Network Connections” on
page 96.
v You can disconnect from the ISP after a certain period of time by overriding the
line inactivity timeout. To do this, select ″Override line activity timeout″ and
specify the ″Timeout″ value in seconds. In this way, you will not be charged by
the ISP for idle time.
Click the TCP/IP Settings tab.
v Select Dynamically assign to indicate that you want IGN to dynamically assign
both the local and remote IP addresses.
Chapter 4. Configuring Point-to-Point TCP/IP (PPP and SLIP)

v Click Routing to open the Routing dialog.
v For static routing, specify Add remote system as the default route. Since you
do not know the range of destination IP addresses, you need a default route.
This is the desired configuration when AS/400 dials in to an ISP such as IGN.
The default route forwards packets to the ISP router, which in turn routes the
packets throughout the Internet.
Click the Authentication tab.
v Check ″Enable local system identification.″ IGN requires customers to use the
Password Authentication Protocol (PAP) for authentication. This verifies the
identity of the customer who is using an unencrypted password.
v Specify both a user ID and a password. In this example, the user name is
internet.account.userid. Other ISPs may use CHAP, which uses an encrypted
password. Consult your ISP to learn its requirements for specifying a user name
and password.
Click the Domain Name Server tab.
v Specify the IP address for the Domain Name Server. In this example, the IP
address is 10.11.27.5. When you use an Internet Service Provider (ISP) to
connect to the Internet, you will receive a name server address from the ISP.
This allows you to connect using host names instead of IP addresses for remote
sites. A host name is a way of identifying a system and its IP address.

Example: Connecting two AS/400s using dial-on-demand
In this example, System 1 is a local system with IP address 10.11.25.1 and System
2 is a remote system with IP address 10.11.25.2. To establish a connection:
1. Configure a Dial-only connection profile on System 1.
2. Configure a Switched line-answer connection profile on System 2.
3. Start connection profiles on System 1 and System 2 by using Operations
Navigator.
4. Verify configurations on System 1 and System 2 by using TELNET.

Configure a Dial-only connection profile on System 1
1. Access Point-to-Point functions through Operations Navigator.
2. From New Point-to-Point Profile Properties dialog, click the General tab and
do the following:
v Type DODBP in the Name text box.
v Type Basic Dial on Demand Profile in the Description text box.
v Under Type, select PPP.
v Under Mode, select Dial-on-demand (dial only).
3. Click the Connection tab and do the following:
v Type the phone number of the remote system.
v Under Line, select a line pool from the Name list.
v Select Override line activity timeout and specify 300 seconds, or five
minutes, as the Timeout value.
4. Click the TCP/IP Settings tab and then do the following:
v Under Local IP Address, click the radio button and type 10.11.25.1 in the
text box.
v Under Remote IP Address, the Remote IP Address is 10.11.25.2.

OS/400 TCP/IP Configuration and Reference V4R4

v Check Allow IP forwarding.
5. Click the Authentication tab and then ensure that local and remote system
identification are not checked.
6. Click OK to save the configuration.

Configure a Switched line-answer connection profile on System
2
1. Access Point-to-Point functions through Operations Navigator.
2. From New Point-to-Point Profile Properties dialog, click the General tab and
then do the following:
v Type DODANS in the Name text box.
v Type Basic Answer Profile in the Description text box.
v Under Type, select PPP.
v Under Mode, select Switched line-answer.
3. Click the Connection tab and then select a line description from the Name list.
4. Click the TCP/IP Settings tab and do the following:
v Under Local IP Address, click the radio button and type 10.11.25.2 in the
text box.
v Under Remote IP Address, the Remote IP Address is 10.11.25.1.
v Check Allow IP forwarding.
5. Click the Authentication tab and then ensure that local and remote system
identification are not checked.
6. Click OK to save the configuration.

Start connection profiles on System 1 and System 2
Once you have started the connection profiles, each connection profile has the
following status:
v System 1: DODBP connection profile: Waiting for dial-Switched line-dial on
demand
v System 2: DODANS connection profile: Waiting for incoming call

Verify configurations on System 1 and System 2 using TELNET
Use TELNET to verify that you can dial and connect to System 2 from System 1
using the DODBP and DODANS connection profiles.
v From the command line on System 1, type
TELNET '10.11.25.2'

and press Enter.
The AS/400 logon screen on System 2 displays if the connection is successful.
The TELNET session ends after 5 minutes of inactivity. Both connection profiles are
reset and wait for the next call.
While the DODBP profile is in the Waiting for dial — Switched line-dial on demand
status, System 1 will dial System 2 when IP packets arrive for System 2.

Chapter 4. Configuring Point-to-Point TCP/IP (PPP and SLIP)

Example: AS/400 Office-to-Office Scenarios
In this scenario, AS400 (LCL400) is set up to answer incoming calls from one of the
following:
v Another AS400 (RMT400), along with its Ethernet and token-ring network
v A remote gateway, along with the Ethernet network attached to it
v An individual remote user

Figure 73. Office-to-Office Remote Connection

This can be accomplished using one connection, such as a phone line with an
attached modem, and only one point-to-point connection profile on LCL400. This is
done by configuring LCL400 to administer different remote IP addresses and routes
based on the incoming caller’s user ID. Since the user ID is used, the remote
system dialing in must use some sort of authentication. For SLIP, this would be
done with a connection script.
This example uses a PPP connection using CHAP authentication. This
authentication protocol was chosen to ensure that only encrypted authentication
information is passed between the systems.
You can configure LCL400 to accept calls from many other user IDs as well, giving
it the flexibility of having tailored IP address and routes for each caller’s
environment. Figure 73 shows an example of this configuration.

Scenario Definitions
Office-to-Office Connection (RMT400 - LCL400)
RMT400 is a remote office with a Token Ring and Ethernet network attached to
it. Either periodically or for a specified time period during the day, RMT400 dials
into LCL400 using a PPP connection. The users in the remote office need to be
able to access LCL400 as well as the 10.1.1.0 Ethernet network attached to
LCL400. Conversely, the users on the 10.1.1.0 network need access to the
10.2.1.0 and 10.2.2.0 networks attached to RMT400. Information about how to
configure both LCL400 and RMT400 to accomplish this task is covered shortly.
Remote User to Office (LCL400)
A remote user could be any user who dials into LCL400 from a PC or
workstation. For example, a remote user is someone who is travelling and
wishes to connect to the home office. The user dialing in also needs access to
the 10.1.1.0 Ethernet network that is attached to LCL400.

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Remote Network to Office (LCL400)
Remote Gateway (non-AS400) is a gateway that is attached to an Ethernet
network. Remote Gateway could call LCL400 during the night to allow systems
on the Remote Gateway’s Ethernet network (192.68.2.0) to transfer files to
either LCL400 or its attached network. Remote Gateway also allows the
forwarding of mail to a mail server on the 192.68.2.0 network.

Configuring LCL400 for all Scenarios
Access Point-to-Point functions through Operations Navigator.
From the General page, perform the following tasks:
v
v
v
v

Specify a profile name (LCL400 for this example).
Select PPP as the ″Type.″
Specify Switched line-answer as the ″Mode.″
(Optional) Specify a description.

From the Connection page, perform the following tasks:
v Select an existing PPP line from the drop-down box and click Open. In this
example, the line 400ANSWER is used.
If an existing line does not exist, you can create a new one by specifying the
name and clicking New.
v From the Modem page on the Line Properties dialog, select a modem from the
modem name pull-down box and click OK.
From the Authentication page, perform the following tasks:
v Select ″Require remote system identification.″
v Ensure that CHAP only is selected.
v Select an existing validation list from the validation list drop-down box and click
Open. In this example, the validation list OFFICE_400 is used.
If a new validation list is required, create a new one by specifying the name and
clicking New.
Figure 74 shows the Validation List dialog.

Figure 74. Validation List

The following values hold true for this example of the Validation List dialog:
v The user IDs RMTOFFICE and RMTGATEWAY have been added for CHAP
authentication.
v RMTOFFICE is the user ID for RMT400 to dial in to LCL400.
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v RMTGATEWAY is the user ID that is used by the remote gateway to dial in to
LCL400.
From the TCP/IP Settings page, perform the following tasks:
v Set your local IP address. In this example, the existing Ethernet interface
10.1.1.1 is selected from the ″Local IP address″ pull-down box.
v Set your remote IP address. In this example, ″Route specified″ is selected. This
signifies that remote IP addresses will be defined from entries that are defined
from the Routing dialog.
Note: ″Route specified″ is valid only for Switched Line-Answer profiles.
v Check ″Allow IP forwarding.″ IP packets that originate from the remote system
will be allowed to flow through LCL400 to the 10.1.1.0 network.
v Click Routing to add the ″Route specified″ IP addresses.
Figure 75 shows the Routing dialog.

Figure 75. Routing

The following values hold true for this example of the Routing dialog:
v RMTGATEWAY user ID (from the Remote Gateway)
When user RMTGATEWAY dials in, he or she receives IP address 192.168.2.6. A
subnet mask of 255.255.255.0 was used to allow LCL400 to add a direct route to
the 192.168.2.0 network that is attached to the Remote Gateway.
v RMTOFFICE user ID (from system RMT400)
When user RMTOFFICE dials in, he or she receives IP address 10.2.1.1. A
subnet mask of 255.255.255.0 was used to allow LCL400 to add a direct route to
the 10.2.1.0 network that is attached to RMT400.
A route was defined for RMTOFFICE. The destination network is 10.2.0.0 with a
subnet mask of 255.255.0.0. This route is added when RMTOFFICE dials in and
allows LCL400 to have access to any 10.2.x.x network that is attached to
RMT400. In this scenario, this would include the 10.2.1.0 network, which is also
covered by the direct route that was added for the interface, as well as the
10.2.2.0 network. If any other 10.2.x.x networks are added to RMT400, the
necessary route to reach them is already defined.

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In this scenario, the IP addresses that are used for the PPP connection allow for
what is known as an ’Unnumbered Net.’ It is called this because no new
networks or IP addresses were created for the connection. The IP address of the
Ethernet connection to LCL400 (10.1.1.1) is used as the remote address for
RMT400. The IP address of the Ethernet connection to RMT400 (10.2.1.1) is
used as the remote address for LCL400.
v If a user other than RMTOFFICE or RMTGATEWAY dials in, then he or she
receives IP address 10.1.1.99. This is accomplished by using the wildcard user
entry * (asterisk), which indicates that if the caller’s user ID is not found in the
list, then this IP address is used as the default. This action assumes the user has
been previously added to the OFFICE_400 validation list.
In the scenario, the remote user receives 10.1.1.99 as the IP address. He or she
also has access to the 10.1.1.0 network with no additional routing required.
Note: 10.1.1.99 has a subnet mask of 255.255.255.255 and is a subset of the
local 10.1.1.0 network. This is known as ″transparent subnetting″ (also
known as Proxy ARP) and allows for the remote user to appear to be on
the same Ethernet network that is attached to LCL400. See the example
in “Example: Remote LAN Access with Transparent Subnetting” on
page 104 for additional information about transparent subnetting.
If only explicitly defined callers can dial in, then you should omit the * entry. All
other callers are then denied access to LCL400.

Configuring RMT400 to Dial into LCL400
Access Point-to-Point functions through Operations Navigator.
From the General page, perform the following tasks:
v Specify a profile name (RMT400 for this example).
v Select PPP as the ″Type.″
v Specify Switched line-dial as the ″Mode.″
v You have the option of specifying a description.
From the Connection page, perform the following tasks:
v In this example, the phone number to connect to LCL400 is 798-1234. The (dash) is optional.
v Select an existing PPP line from the drop-down box and click Open. In this
example, the line 400DIAL is used.
If an existing line does not exist, you can create a new one by specifying the
name and clicking New.
v From the Modem page on the Line Properties dialog, select a modem from the
modem name pull-down box and click OK.
From the Authentication page, perform the following tasks:
v Select ″Enable local system identification.″
v Ensure that CHAP only is selected.
v The user ID that will be used to identify RMT400 when it dials a remote system
is RMTOFFICE.
Note: The user ID and password must be the same as those that you defined in
the OFFICE_400 validation list on LCL400.
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From the TCP/IP Settings page, perform the following tasks:
v Set your local IP address. In this example, the existing Ethernet interface
10.2.1.1 is selected from the ″Local IP address″ pull-down box.
v Set your remote IP address. In this example, ″Dynamically assigned″ is selected.
The remote system, LCL400, defines the address that RMT440 uses when the
connection is established.
The remote address of 10.1.1.1, which is the local Ethernet IP address for
LCL400, could have been defined statically for RMT400. If this address ever
changes, however, you must update the profile. The value ″Dynamically
assigned″ allows it to work for whatever address LCL400 has specified.
v Since you need to define additional routes, click Routing.
Figure 76 shows the Routing dialog.

Figure 76. Routing

The following values hold true for this example of the Routing dialog:
v Select ″Use static routes″ Static routing. If RMT400 only ever called LCL400,
then you could have selected ″Add remote system as the default route.″ This
ensures that all TCP/IP traffic would go to LCL400 if not otherwise defined. In
this example, however, assume that RMT400 has other point-to-point profiles that
can call other remote systems at the same time. Therefore, we want to define
network routes to the remote networks.
v A route is defined for remote network 10.1.0.0 with a subnet mask of
255.255.0.0. This route is added when the connection is made with LCL400. All
TCP/IP traffic for hosts on the 10.1.x.x network are sent to LCL400. Currently,
this is only 10.1.1.0. If other 10.1.x.x networks are added to LCL400 in the future,
then no further routing will need to be defined to reach hosts on the other
networks.

Example: Remote LAN Access with Transparent Subnetting
Transparent Subnetworking allows remote clients who are on separate LANs to
communicate with one another as if they were on the same physical network. To
accomplish transparent subnetworking from the home network, you must partition
blocks of addresses for each remote site. The subnet and the host are the two
levels of hierarchical addressing. The boundary between them is arbitrary.

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For example, you can have 255 partitions with each partition having 255 host
addresses available. You can then manage which partitions are assigned to remote
networks. Each remote network partition is mapped to the subnet (see Figure 77).
AS/400 hides the fact that the remote networks are physically located behind
AS/400. It will then act as a proxy and forward the datagram packets to the remote
networks. When transparent subnetting is put into effect, the remote host appears
to be part of the physical corporate network.
Transparent subnetworking is useful in environments in which it is either impractical
or impossible to run routing protocols. Such a situation might occur in a bridged
network or in networks that are running unsupported proprietary dynamic routing
protocols. This is best suited for leased line connections when remote sites need to
communicate with one another. If remote sites do not need to communicate with
each other, however switched line connections are viable.
Figure 77 shows an example of how an network configuration could use transparent
subnetting for remote LAN access.

Figure 77. Example Configuration for Remote LAN Access with Transparent Subnetting

Note: This diagram shows PPP links carrying out unnumbered networking. The IP
address that is used to connect the home network (10.5.0.0) to AS/400
(10.5.0.1) with a subnet mask of 255.255.0.0 is the same local IP address
that is used for all remote dial-up connections. No IP addresses are required
to be assigned to the PPP links.
The following steps are an example of how to configure AS/400 to connect to
multiple LAN subnets. The example uses a single PPP answer profile to put
transparent subnetting into effect, based on Figure 77.

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Creating a Point-to-Point Profile for LAN Transparent Subnetting
Access Point-to-Point functions through Operations Navigator.
From the General page, perform the following tasks:
v Specify a profile name (REMOTE_ABC for this example).
v Specify a description for the connection profile (Answer profile For Remote Box
A, B, or C in this example).
v Select PPP as the ″Type.″
v Select Switched line-answer as the ″Mode.″
From the TCP/IP Settings page, perform the following tasks:
v Specify your ″Local IP address.″ Since this example is Unnumbered Net, an
existing token-ring interface, 10.5.0.1, is selected from the ″Local IP address″
pull-down box.
v Specify your ″Remote IP address.″ In this example, Route specified is selected.
Remote IP addresses will be defined from the entries that are defined in the
Routing dialog.
Note: Route specified is valid only for switched line-answer profiles.
v Check ″Allow IP forwarding.″ IP packets that originate from the remote LAN are
allowed to flow through AS/400 to the ″Corporate Network″ or other remote
LANs.
Click Routing to add entries to the Route specified IP addresses. From the
Routing page, perform the following tasks:
v For ″Dynamic routing,″ select None. Routing will be carried out through static
routing.
v For ″Static routing,″ select Use static routes:
– Caller REMOTE_A receives IP address 10.5.1.1. A subnet mask of 255.255.255.0
allows AS/400 to add a direct route to the 10.5.1.0 network.
– Caller REMOTE_B receives IP address 10.5.2.1. A subnet mask of 255.255.255.0
allows AS/400 to add a direct route to the 10.5.2.0 network.
– Caller REMOTE_C receives IP address 10.5.3.1. A subnet mask of 255.255.255.0
allows AS/400 to add a direct route to the 10.5.3.0 network.
Note: You can add more routes if additional LANs are attached to AS/400
through subnetting.
Figure 78 on page 107 shows the Routing dialog.

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Figure 78. Example Routing for Transparent Subnetting

Validation List: Click the Authorization tab; then click New or Open to enter
authorization information.
1. Add a validation list for remote LANs A, B, and C by using PAP or CHAP
authentication.
2. Click OK when the validation list is completed.
3. Click OK to close the connection profile properties page.

Example: Remote LAN Access with Dynamic Routing (RIP)
Remote LAN access with dynamic routing allows remote clients on separate LANs
to communicate with one another as if they were on the same routing domain. It
enables any host in the corporate network to communicate with any remote LAN
host. Dynamic routing from the home network places no address restrictions on the
remote network. Further, there is no need for a hierarchical address scheme or
relationship from the host to the home address space.
The home network is able to learn about the remote networks by using a dynamic
routing algorithm within the home network using RIP 1 or 2. This is accomplished
by the home network updating its routing tables as information is extracted from the
remote networks static routing table.
The number of remote networks directly affects the size of the dynamic routing
tables. No dynamic routing protocols run on the remote PPP links. Instead, they are
run by AS/400 and the corporate network. The routing protocol automatically
redistributes remote routes throughout the corporate network.
A solution where the corporate network is running RIP 1 or 2 as its routing protocol
and the remote links are connecting to a small amount of networks would be to
implement remote LAN access with dynamic routing. If RIP 1 or 2 is being run in
AS/400, the static routes will automatically be redistributed. This eliminates the
need to run RIP over the remote links.
Figure 79 on page 108 shows an example of how a network configuration could use
RIP for remote LAN access.

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Figure 79. Example Configuration for Remote LAN Access with Dynamic Routing (RIP)

Creating a Point-to-Point Profile for LAN Access with Dynamic
Routing (RIP)
Access Point-to-Point functions through Operations Navigator.
From the General page, perform the following tasks:
v Specify a profile name (REMOTE_ABC for this example).
v Select PPP as the ″Type.″
v Select Switched line-dial as the ″Mode.″
From the TCP/IP Settings page, perform the following tasks:
v Specify your ″Local IP address.″ Since this example is Unnumbered Net, an
existing token-ring interface, 10.5.0.1, is selected from the ″Local IP address″
pull-down box.
v Specify your ″Remote IP address.″ In this example, Route specified is selected.
Remote IP addresses are defined from the entries that are defined in the
Routing dialog that appears when you click Routing.
Note: Route specified is valid only for switched line-answer profiles.
v Check ″Allow IP forwarding.″ IP packets that originate from the remote LAN are
allowed to flow through AS/400 to the ″Corporate Network″ or other remote
LANs.
Click Routing to add entries to the Route specified IP addresses. From the
Routing page, perform the following tasks:
v For ″Dynamic routing,″ select None. Routing will be accomplished through static
routing. RIP is used within the ″Corporate Network″ but not on remote links.
v For ″Static routing,″ select Use static routes:
– Caller REMOTE_A receives IP address 192.168.4.1. A subnet mask of
255.255.255.0 allows AS/400 to add a direct route to the 192.168.4.0 network.

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– Caller REMOTE_B receives IP address 192.168.139.1 A subnet mask of
255.255.255.0 allows AS/400 to add a direct route to the 192.168.139.0
network.
– Caller REMOTE_C receives IP address 192.168.57.1. A subnet mask of
255.255.255.0 allows AS/400 to add a direct route to the 192.168.57.0
network.
Note: You can add more routes if additional LANs are attached to AS/400
through subnetting.
Figure 80 shows the Routing dialog.

Figure 80. Example Routing for Dynamic Routing

Monitoring Activity
You use Operations Navigator to create, change, view, start or stop a PPP
connection profile using the new PPP line type. After you configure a PPP
connection profile, you can start, stop, or delete it. To do this, right click the
connection profile you want in Operations Navigator’s tree view. Then, select Start,
Stop, or Delete from the context menu.
The Connection Profile list also allows you to monitor several things about a
point-to-point job by scrolling left or right on the window. The Status indicator tells
whether the connection is starting, in use, or ending. A value of Inactive specifies
that no jobs are currently running for that profile. A value of Ended - information
available, on the other hand, indicates that the connection has ended and that
information is available for that job. Examples of other status values that occur
while the job is running include Session job starting, Waiting for incoming call,
and Active.
Scroll to the right in the Connection Profile list to display more information. From
here, information can be gathered about a particular job. By using a combination of
the values for Job number, Job user, and Job, you can look at additional information
such as Point-to-Point Messages, Jobs, and Printer Output information. For
additional information, see “Point-to-Point Jobs” on page 110.

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Point-to-Point Jobs
You can look at messages and jobs in Operations Navigator’s tree view.

Messages
To display a list of messages as a result of a job, click Messages in Operations
Navigator tree view.
The first time you display this dialog, the messages will be for the current user.
However, these jobs run in the QSYSWRK subsystem under user QTCP. Therefore,
it is necessary to display the messages for QTCP to see the messages for the job.
To display messages for QTCP, select Include from the Options menu.
Select ″User name″ and specify QTCP in the space. Click OK. You will be returned to
the Include dialog. Click OK. ″Messages for QTCP″ will be displayed in the
message line. From here, you will be able to see messages pertaining to the profile
that you have started or stopped. Find the message that you are interested in and
double-click it in the From user column. This will bring up the detailed message
information dialog with a thorough explanation of the message.

Jobs
To look at information for an active job or a job that has completed, click Jobs in
Operations Navigator tree view. You will now have to perform a similar search as
you did for messages.
Select Include from the Options menu. For an active job, fill in ″User″ with QTCP,
″Job name″ with All, and click OK. In addition for a completed job, select Yes for
″Show completed jobs with printer output.″
A list of all jobs for QTCP will be displayed on the right side of the window. From
here, you can look at the information that is available for the job.
Point-to-point job names start with the string QTPP, where dial-out jobs are
QTPPDIALnn and dial-in jobs are QTPPANSnn. The number string nn is sequential
from 1 to 99. Find your job name in the list and right-click the desired job name.
From the context menu, select Job Log for an active job.
Double-clicking a Message ID value displays detailed message information.
Double-clicking the Output name value displays a viewer dialog with information on
the completed job.

Printer Output
To look at printer output for a job that has completed, click Printer Output in
Operations Navigator tree view. Next, select Include from the Options menu. Fill in
the user with QTCP as explained in “Messages” and click OK. From here, you can
look at the User specified data column and find your job name. Double-clicking the
Output name value displays information about the job.

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If you wish to narrow your search and do not wish to see all QTCP jobs, you can
specify AS/400 job name on the Include dialog. The job name consists of three
parts: Job number, Job user, and Job name.

Optional Monitoring of Point-to-Point Activity
An optional method to monitor activity for Point-to-Point connection profiles is to
invoke option 14 from the Work with Point-to-Point TCP/IP (WRKTCPPTP)
command on a 5250 AS/400 console. For more information about this option, see
“Monitoring Point-to-Point Activity” on page 134.

Connection Alternatives
This section provides you an overview of the link layer connection alternatives
available to you.
Point-to-point links establish a physical connection between a local and remote
host. When connected, these links provide dedicated bandwidth and come in a
variety of data rates and protocols. With point-to-point links, you can choose from
dial-up analog modem connections, leased analog lines, and switched and leased
digital services of various kinds.
PPP is a method of transmitting datagrams over serial point-to-point links. PPP
enables interconnection of multiple vendor equipment and multiple protocols by
standardizing point-to-point communications. The PPP data link layer uses
HDLC-like framing for encapsulating datagrams over both asynchronous and
synchronous point-to-point telecommunication links.
While PPP supports a wide range of link types, SLIP is limited to asynchronous link
types. SLIP is generally employed only for analog links.
Local telephone companies offer traditional telecommunications services in an
ascending scale of capabilities and cost. These services use existing telephone
company voice network facilities between customer and central office. A comparison
of communication services and their relative costs is shown in Table 8. The costs
shown are not intended to reflect current pricing. Instead, they are intended to
show relative differences between services. Cost rates on leased lines are usually
distance-based, while the switched lines may also be time-based.
Note: The following table is for illustration purposes only. It does not include all
supported AS/400 configurations. The costs shown are not intended to reflect
current pricing.
Table 8. Comparison of communication services and relative costs
Service

Line Speed

Required
Equipment

DTE/DCE
Interface

Relative Cost
(per month)

Analog (leased
and switched)

33.4Kbps or less Modem

RS232
asynchronous

Digital Data
Service (DDS)

56.0Kbps or less CSU/DSU

X.21/V.35/RS$50-$500
449 synchronous

Switched-56

56.0Kbps

CSU/DSU with
V.25bis dial

V.35/RS-449
synchronous

$20-$150

$50-$250

Chapter 4. Configuring Point-to-Point TCP/IP (PPP and SLIP)

111

Table 8. Comparison of communication services and relative costs (continued)
Line Speed

Required
Equipment

DTE/DCE
Interface

ISDN switched

56, 64, 112, or
128Kbps

ISDN terminal
adapter

RS232
asynchronous

Fractional T1

56Kbps to
1.544Mbps

CSU/DSU or T1
mux

X.21/V.35/RS449
$100-$2,000
synchronous

T1/E1

56Kbps to
1.544/2.048
Mbps

CSU/DSU or T1
mux

X.21/V.35/RS449
$350-$2,000
synchronous

Service

Relative Cost
(per month)
$50-$250

Analog Phone Lines
The analog connection, which uses modems to carry data over leased or switched
lines, sits at the bottom of the point-to-point scale. Leased lines are full-time
connections between two specified locations, while switched lines are regular
voice-phone lines.
The fastest modems today operate at an uncompressed rate of 33.6Kbps. Given
the signal-to-noise ratio on unconditioned voice-grade telephone circuits, though,
this rate is often unattainable. Modem manufacture claims of higher bit-per-second
(bps) rates are usually based on a data compression (CCITT V.42bis) algorithm that
is utilized by their modems.
Although V.42bis has the potential to achieve as much as four-fold reduction in data
volume, compression depends on the data and rarely reaches even 50%. Data
already compressed or encrypted may even increase with V.42bis applied.
Emerging technology referred to as X2 or 56Flex extends the bps rate to 56k for
analog telephone lines. This is a hybrid technology that requires one end of the
PPP link to be digital while the opposite end is analog. Additionally, the 56Kbps
applies only when you are moving data from the digital toward the analog end of
the link. This technology is well suited for connections to ISPs with the digital end of
the link and hardware at their location.
Typically, you can connect to a V.24 analog modem over an RS232 serial interface
with an asynchronous protocol at rates up to 115.2Kbps.

Digital Data Service
With digital, data travels all the way from the sender’s computer to the central office
of the telephone company, to the long distance provider, to the central office, and
then to the computer of the receiver in digital form. Digital signaling offers much
more bandwidth and higher reliability than analog signaling. A digital signaling
system eliminates many of the problems that analog modems must deal with, such
as noise, variable line quality, and signal attenuation.

DDS
The most basic of digital services is called Digital Data Services (DDS). DDS links
are leased, permanent connections, running at fixed rates of up to 56Kbps. This
service is also commonly designated as DS0.

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You can connect to DDS using a special box called Channel Service Unit/Data
Service Unit (CSU/DSU), which replaces the modem in the analog scenario. DDS
has physical limitations that are primarily related to the distance between the
CSU/DSU and the Telephone Company Central Office. DDS works best when
distance is less than 30,000 feet. Telephone companies can accommodate longer
distances with signal extenders, but this service comes at higher cost. DDS is best
suited for connecting two sites that are served by the same Central Office. For long
distance connections that span different Central Offices, mileage charges can
quickly add up to make DDS impractical. In such cases, Switched-56 may be better
solution.
Typically, you can connect to a DDS CSU/DSU over V.35, RS449, or X.21 serial
interface with synchronous protocol at rates up to 56Kbps.

Switched-56
When you do not need a full-time connection, you can save money by using
switched digital service, which is generally called Switch-56 (SW56). An SW56 link
is similar to DDS setup in that the DTE connects to the digital service by way of
CSU/DSU. An SW56 CSU/DSU, however, includes a dialing pad from which you
enter the phone number of the remote host.
SW56 lets you make dial-up digital connections to any other SW56 subscriber
anywhere in the country or across international borders. An SW56 call is carried
over the long distance digital network just like a digitized voice call. SW56 uses the
same phone numbers as the local telephone system, and usage charges are the
same as those for business voice calls.
SW56 is available only in North American networks, and it is limited to single
channels that can only carry data. SW56 is an alternative for locations where ISDN
is unavailable.
Typically, you can connect to a SW56 CSU/DSU over V.35 or RS 449 serial
interface with synchronous protocol at rates up to 56Kbps. With a V.25bis
call/answer unit, data and call control flow over a single serial interface.

ISDN
Like Switched-56, ISDN also provides switched end-to-end digital connectivity.
Unlike other services, however, ISDN can carry both voice and data over the same
connection.
There are different types of ISDN services, with Basic Rate Interface (BRI) being
the most common. BRI consists of two 64Kbps B channels to carry customer data
and a D channel to carry signaling data. The two B channels can be linked together
to give a combined rate of 128Kbps. In some areas, the phone company may limit
each B channel to either 56Kbps or 112Kbps combined.
There is also a physical constraint in that the customer location must be within
18,000 feet of the central office switch. This distance can be extended with
repeaters.
You can connect to ISDN with a device called a terminal adapter. Most terminal
adapters have an integrated network termination unit (NT1) that allows direct
connection into a telephone jack. Typically, terminal adapters connect to your
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113

computer over an asynchronous RS232 link and use the AT command set for setup
and control, much like conventional analog modems. Each brand has its own AT
command extension for setting up parameters that are unique to ISDN. In the past,
there were many interoperability problems between different brands of ISDN
terminal adapters. These problems were due mostly to the variety of rate adaptation
protocols that were available in V.110 and V.120 as well as bonding schemes for
the two B channels. The industry has now converged to synchronous PPP protocol
with PPP multilink for linking two B channels.
Some terminal adapter manufactures integrate V.34 (analog modem) capability into
their terminal adapters. This enables customers with a single ISDN line to handle
either ISDN or conventional analog calls by taking advantage of the simultaneous
voice/data capabilities of ISDN services. New technology also enables a terminal
adapter to operate as the digital server side for 56K(X2/56Flex) clients.
Typically, you would like to connect to an ISDN terminal adapter over an RS232
serial interface using asynchronous protocol at rates up to 230.4Kbps. However, the
maximum AS/400 baud rate for asynchronous over RS232 is 115.2Kbps.
Unfortunately, this restricts the maximum byte transfer rate to 11.5k bytes/sec, while
the terminal adapter with multi-linking is capable of 14/16k bytes uncompressed.
Some terminal adapters support synchronous over RS232 at 128Kbps, but AS/400
maximum baud rate for synchronous over RS232 is 64Kbps. The AS/400 is capable
of running asynchronous over V.35 at rates up to 230.4Kbps, but terminal adapter
manufacturers generally do not offer such a configuration. Interface converters that
convert RS232 to V.35 interface could be a reasonable solution for the problem, but
this approach has not evaluated for AS/400. Another possibility is to use terminal
adapters with V.35 interface synchronous protocol at rate of 128Kbps. Although this
class of terminal adapters exists, it does not appear that many offer synchronous
Multilink PPP.

T1/E1
A T1 connection bundles together twenty-four 64Kbps (DS0) time division
multiplexed (TDM) channels over 4-wire copper circuit. This creates a total
bandwidth of 1.544Mbps. An E1 circuit in Europe and other parts of the world
bundles together thirty-two 64Kbps channels for a total of 2.048Mbps.
TDM allows multiple users to share a digital transmission medium by using
pre-allocated time slots. Many digital PBXs take advantage of T1 service to import
multiple call circuits over one T1 line instead of having 24 wire pairs routed between
the PBX and telephone company.
It is important to note that T1 can be shared between voice and data. A company’s
telephone service may come over a subset of a T1 link’s 24 channels, for instance,
leaving remaining channels available for internet connectivity.
A T1 multiplexer device is needed to manage the 24 DS0 channels when a T1 trunk
is shared between multiple services. For a single data-only connection, the circuit
can be run unchannelized (no TDM is performed on the signal). Consequently, a
simpler CSU/DSU device can be used.
Typically, you can connect to a T1/E1 CSU/DSU or multiplexer over V.35 or RS 449
serial interface with synchronous protocol at rates at a multiple of 64Kbps to
1.544Mbps or 2.048Mbps. The CSU/DSU or multiplexer provides the clocking in the
network.

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Fractional T1
With Fractional T1 (FT1), a customer can lease any 64Kbps sub-multiple of a T1
line. FT1 is useful whenever the cost of dedicated T1 would be prohibitive for the
actual bandwidth customer uses.
With FT1 you pay only for what you need. Additionally, FT1 has the following
feature that is unavailable with a full T1 circuit: Multiplexing DS0 channels at the
telephone company’s central office. The remote end of an FT1 circuit is at a Digital
Access Cross-Connect Switch that is maintained by the telephone company.
Systems that share the same digital switch can switch among each other’s DS0
channels. This scheme is popular with ISPs that use a single T1 trunk from their
location to the telephone company’s digital switch. In these cases, multiple clients
can be served with FT1 service.
Typically, you can connect to a T1/E1 CSU/DSU or multiplexer over V.35 or RS 449
serial interface with synchronous protocol at some multiple of 64Kbps. With FT1,
you are pre-allocated a subset of the 24 channels. The T1 multiplexer must be
configured to fill only the time slots that are assigned for your service.

Using an Asynchronous Modem or ISDN Terminal Adapter
|
|
|

This material is covered in the AS/400e Information Center under the TCP/IP
topic. For more information see “TCP/IP Topics in the Information Center” on
page xv.

PPP ISDN Support
|
|
|

This material is covered in the AS/400e Information Center under the TCP/IP
topic. For more information see “TCP/IP Topics in the Information Center” on
page xv.

Configuring SLIP Connection Profiles
This section covers sample property sheets for configuring a Serial Line Interface
Protocol (SLIP) Point-to-Point network connection profile using Operations
Navigator. There is very little difference in how a SLIP connection profile is created
and used from how a PPP connection profile is created and used. This section will
mainly point out any features that are unique to SLIP. Refer to previous PPP
sections for more details on the property pages. You can also refer to the PPP
scenarios in the previous section. These scenarios will also work for SLIP.
Note: This section does not cover how to create SLIP point-to-point connection
profiles (which use *ASYNC lines). For more information on creating SLIP
point-to-point connection profiles, see “Using SLIP with an Asynchronous
Line Description” on page 126.
The General page allows you to define the following general attributes of a
connection profile:
v Name of the profile
v Optional description for the profile
v Which protocol to use (SLIP in this example)
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115

v Operating mode which helps to define the physical connection (switched
line-answer in this example)
The Connection page allows you to define the line description that will be used for
the connection. For switched dial profiles, this page also allows you to specify the
remote phone number or numbers required to connect to the remote system. For
SLIP, the ″Maximum transmission units″ is configurable. This determines the size in
bytes of each Packet that is sent to the remote system.
The TCP/IP Settings page allows you to define the local and remote IP addresses
that will be used for this connection. It also allows you to define additional TCP/IP
attributes.
For the remote IP address, ″Route specified″ is enabled only for switched
line-answer profiles. This gives the administrator greater flexibility in selection of
remote IP addresses. If the IP forwarding option is selected, then this allows the
remote user to send IP datagrams to the network that is connected to this AS/400.
If this is not desirable, then disable this feature. VJ header compression is not
configurable on the answer side since the client determines if VJ header
compression will be used.
Dynamically assigned IP addresses require the use of a connection script. For more
information, see “Writing Connection Dialog Scripts” on page 118.
Use the Script page to specify whether you want to use a connection script for the
connection profile.
A Connection script allows AS/400 and remote systems to exchange information.
This is the only method of passing user ID, password, and IP address information
for SLIP. For more information, see “Writing Connection Dialog Scripts” on
page 118.
Use the Domain Name Server page to define the domain name server to use for a
connection profile. The page is enabled for switched line-dial and leased
line-initiator connection profiles only.
You may want to configure the Domain Name Server (DNS) under the following
conditions:
v You want to have automatic host-name-to-IP-address resolution
v The remote system has a DNS available
If authentication is required, use the Authentication page to define which users
may connect to this system.
Figure 81 on page 117 is an example of a switched answer or leased line terminator
authentication page for a SLIP connection profile. If authentication is enabled, then
a connection script must be used to prompt for and accept the user name and
password information from the remote system. For more information on connection
scripts, see “Writing Connection Dialog Scripts” on page 118.

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Figure 81. SLIP Connection Profile Properties - Authentication (Answer)

The validation list name is the name of the validation list object that contains a list
of the user names that may connect to this system as well as their passwords. To
open a validation list name, click Open on the Authentication page.
Figure 82 is an example of a switched dial or leased line initiator authentication
page for a SLIP connection profile. This page is used to define the user name and
password that will be used to identify this system when connecting to a remote
system.

Figure 82. SLIP Connection Profile Properties - Authentication (Dial)

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117

If authentication is enabled, then a connection script must be used to pass the user
name and password information to the remote system. For more information on
connection scripts, see “Writing Connection Dialog Scripts”.

Writing Connection Dialog Scripts
A connection dialog script is information in an AS/400 source file that AS/400 uses
to exchange data prior to establishing a SLIP (or in some cases a PPP) connection.
Note: Your AS/400 does not support the capability to select SLIP or PPP service
from a connection dialog script when a remote system dials AS/400.
The configuration profile determines which connection script is used. The dialog text
must exactly match the connection sequence that is exchanged between AS/400
and a remote system.
Each connection script contains the dialog text required for the exchange of
authorization and connection parameters with a remote host. The configuration
profile determines which connection script is to be used. The dialog text must be an
exact match for the connection to be established between the client and server or
client and ISP.
Note: AS/400 expects each input line of dialog text from the remote system to end
with an end-of-line character. See “Rules for Creating and Changing
Connection Scripts” on page 119 for further details.

Connection Script Considerations for SLIP
For SLIP on an AS/400, connection dialog scripts commonly perform the following
functions:
v Exchange sign-on and password information to authorize an AS/400 to connect
to a remote host or ISP
v Exchange sign-on and password information to authorize a remote host to
connect to an AS/400
v Select the type of service requested (for example SLIP or PPP) from an ISP
v Allow the dynamic assignment of an IP address by an ISP to an AS/400
v Allow AS/400 to assign an IP address dynamically to a remote host
If you do not require these functions for SLIP connections to or from an AS/400,
you do not need to use a connection script. If you do not use connection dialog
scripts, though, AS/400 will establish SLIP connections without user ID or password
authentication.

Creating and Changing Connection Scripts
You cannot change the default connection script file QUSRSYS/QATOCPPSCR.
You must first create your own connection script file. Do this by copying the default
file as follows:
CPYF FROMFILE(QUSRSYS/QATOCPPSCR)
TOFILE(lib/file) FROMMBR(*ALL)
TOMBR(*FROMMBR) MBROPT(*ADD)
CRTFILE(*YES)

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where lib/file represents your own new file, such as QUSRSYS/SLIPSCRIPT.
This creates a new file that uses the existing default connection script file as the
base and that contains all of the same data. You can now change the data for your
use.
You must refer to the new connection script file name in the TCP/IP point-to-point
configuration profile that will use the new connection script.
If you need to use characters in your connection script file that are not supported by
EBCDIC CCSID 500, which is the CCSID of the default connection script, then go
to “NLS Considerations” on page 125.

Rules for Creating and Changing Connection Scripts
There are many special rules for creating and changing connection scripts. The
rules are as follows:
v Column 1 of each line in the connection script may contain a control character.
The control character specifies the action to be taken by AS/400 system. Column
2 may be left blank.
– The AS/400 system ignores comment lines.
Comment lines begin with either an asterisk (*), or are completely blank.
– Output lines for the remote system begin with an ampersand (&)
– To send an asterisk (*) to the remote host, put an ampersand (&) in column 1
followed by an asterisk in column 2.
To send an ampersand (&) to the remote host, put an ampersand in column 1
followed by an ampersand in column 2.

v
v

– A blank line with an ampersand in column 1 will not be sent to the remote
host. Refer to the (PROMPT) keyword for this operation.
The AS/400 system interprets any non-blank line that does not contain one of the
previously described control characters as input from the remote host.
You can mix upper-case and lower-case in a line that contains expected input
from the remote host.
AS/400 translates all input to upper-case before comparing the dialog match text.
AS/400 expects each line of dialog text from the remote system to end with an
end-of-line character, such as a carriage return, New Line, or Line Feed. If this is
not possible, dialog match text may be changed to achieve a match. For
example, if the remote server host prompts for a password with ″Password:″,
then the match text in the connection script may be shortened to ″Pass″ or
″Password″ (the colon character has been omitted).
Fields enclosed in parentheses () contain the keywords that describe an input or
an output operation.

You cannot define the keywords. However, you can control the operations
performed during the connection dialog. To control the operations and the order
in which they run, create a unique connection script using appropriately placed
keywords.
v You cannot change the default connection scripts.
If you need a connection script that is different from all the default ones, you
must copy the default connection scripts and change the copy.
The valid keywords are:

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119

(USERID)
When remote systems dial in, AS/400 uses this keyword to validate the user ID
that the remote system is using to connect to AS/400. The keyword is only valid
if an access authorization list is configured.
When an AS/400 user dials out to a remote system, AS/400 uses this keyword
to pass the user ID to the remote server for connection validation.
If the remote system requires both an account name and a user ID, configure
both as described in “Remote System Access Information” on page 152.
(PASSWORD)
For dial-in sessions, AS/400 uses this keyword to validate the password for the
user ID that was received on the (USERID) keyword. AS/400 uses this keyword
only when an access authorization list is configured.
For dial-out sessions, AS/400 uses this keyword to send the password to the
remote server for connection validation.
(IPADDR)
The IP address to be exchanged and activated to set up a session.
(IPGATE)
The gateway IP address to be exchanged and activated to set up a session.
(PROMPT)
Specifies that AS/400 is to either:
v Pause for input on an input line, or
v Send a blank followed by a carriage return and a line feed for an output line.
This keyword is useful for synchronizing a connection script with a remote
system. Placing this keyword on the input line of a connection script causes the
host to pause until input is received before continuing the dialog. Placing this
keyword on the output line of a connection script causes the host to signify
readiness to continue the dialog. Typically this keyword is placed on the first
line of the connection script to synchronize the host to host connection before
beginning the connection dialog.
Some ISPs may look for specific responses to initiate a SLIP connection. For
example, specific characters like @ , &, or a carriage return without any text may
be required.
To change what AS/400 sends, use the following command:
& (PROMPT) 'xxyy'

where 'xxyy' is the two-digit hexadecimal representation for any ASCII
characters that you wish to send.
For example, & (PROMPT) '4053' would cause AS/400 to send the characters
’@S’, and & (PROMPT) '0D' would cause AS/400 to send only a carriage return.
The hexadecimal representation of the characters to be sent must be two digits
each and represent valid ASCII characters.
(WAIT)
Causes AS/400 to wait 1 second before resuming.
You can cause a time delay from 1 to 99 seconds. To change the time delay,
use the following command:

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(WAIT) 'xx'

where xx is the delay value in seconds. This keyword works the same on both
input and output lines, and is useful for controlling the rate and timing of the
dialog.
You do not need to include all of the connection dialog in the connection script. For
input lines containing a keyword, it is good practice to include some text preceding
the keyword to help AS/400 system locate the expected keyword input. Also, as
previously described, it may be necessary to shorten input match text in order to
obtain a match when connecting to systems that do not send end-of-line characters
at the end of a line.

Location of Default Connection Scripts: You can find the default connection
scripts contained in Table 9. The members are in file QATOCPPSCR.

SLIP Connection Scripts-Examples
The connection scripts in Table 9 are examples for the following:
v Dialing out from AS/400 to a remote host.
v Dialing in to AS/400 from a remote host.
Each member has a different purpose, stated in the comment. Each script is placed
in its own member in file QATOCPPSCR in some connection script library.
Table 9. SLIP Client Connection Scripts-Examples
Client (Dial-Out) Examples
Member DIAL400 in File QATOCPPSCR

Server (Dial-In) Examples

*******************************************************
* CLIENT CONNECTION SCRIPT EXAMPLE
* FOR AS/400 WITH LOGIN AND PASSWORD PROMPT
*******************************************************
& (PROMPT)
login:
& (USERID)
password:
& (PASSWORD)
* END OF CLIENT CONNECTION SCRIPT EXAMPLE

Member ANS400 in File QATOCPPSCR

Member DIAL400I in File QATOCPPSCR

Member ANS400I in File QATOCPPSCR

*******************************************************
* CLIENT CONNECTION SCRIPT EXAMPLE
* FOR AS/400 WITH DYNAMIC IP ADDRESS
*******************************************************
& (PROMPT)
login:
& (USERID)
password:
& (PASSWORD)
YOUR IP ADDRESS IS (IPADDR) MY IP ADDRESS IS (IPGATE)
* END OF CLIENT CONNECTION SCRIPT EXAMPLE

*******************************************************
* SERVER CONNECTION SCRIPT EXAMPLE
* FOR AS/400 WITH DYNAMIC IP ADDRESS
*******************************************************
(PROMPT)
& login:
(USERID)
& password:
(PASSWORD)
& YOUR IP ADDRESS IS (IPADDR) MY IP ADDRESS IS (IPGATE)
* END OF SERVER CONNECTION SCRIPT EXAMPLE

*******************************************************
* SERVER CONNECTION SCRIPT EXAMPLE
* FOR AS/400 WITH LOGIN AND PASSWORD PROMPT
*******************************************************
(PROMPT)
& login:
(USERID)
& password:
(PASSWORD)
* END OF SERVER CONNECTION SCRIPT EXAMPLE

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121

Table 9. SLIP Client Connection Scripts-Examples (continued)
Client (Dial-Out) Examples
Server (Dial-In) Examples
Member DIALAIX in File QATOCPPSCR

Member ANSAIX in File QATOCPPSCR

*******************************************************
* CLIENT CONNECTION SCRIPT EXAMPLE
* FOR AIX 4.1 SLIPLOGIN SCRIPT
*******************************************************
&(PROMPT)
login:
&(USERID)
password:
&(PASSWORD)
Called system's address is (IPGATE)
Calling system's address is (IPADDR)
discipline
* END OF CLIENT CONNECTION SCRIPT EXAMPLE

*******************************************************
* SERVER CONNECTION SCRIPT EXAMPLE
* FOR AIX 4.1 SLIPCALL SCRIPT
*******************************************************
(PROMPT)
& login:
(USERID)
& password:
(PASSWORD)
& Called system's address is (IPGATE)
& Calling system's address is (IPADDR)
& The netmask is 255.255.255.0
& Activating slip line discipline
* END OF SERVER CONNECTION SCRIPT EXAMPLE

Member DIALIGN in File QATOCPPSCR

Member ANSWIN95 in File QATOCPPSCR

*******************************************************
* CLIENT CONNECTION SCRIPT EXAMPLE FOR
* IBM GLOBAL NETWORK (IGN) INTERNET SERVICE
*******************************************************
& &
Enter dial script version ==>
& 1.1
Enter service ==>
& INTERNET
Enter account userID password
& (USERID) (PASSWORD)
(IPADDR) is your IP address.
& (PROMPT)
(IPGATE) is the gateway IP address.
Begin TCP/IP communication now.
* END OF CLIENT CONNECTION SCRIPT EXAMPLE

*******************************************************
* SERVER CONNECTION SCRIPT EXAMPLE
* Windows 95 system with Microsoft Plus for Windows 95
* installed dialing into AS/400 *ANS session.
*******************************************************
(PROMPT)
& Userid:
(USERID)
& Password?
(PASSWORD)
& InternetLR/E>
(PROMPT)
& (IPGATE) IS AS/400 IP ADDRESS.
& (IPADDR) IS IP ADDRESS OF SYSTEM CALLING AS/400.
* END OF SERVER CONNECTION SCRIPT EXAMPLE

Creating SLIP Client (Dial-Out) Connection Scripts-Examples
This topic explains how to create connection scripts for dial-out connections.
The following is an example of a client connection script for a generic (non-IBM
Global Network) ISP:
1.
2.
3.
4.
5.

* Generic client connection script example
& (PROMPT)
Username:
& (USERID)
Password:

6. & (PASSWORD)
7. Protocol:
8.
9.
10.
11.

SLIP
The gateway address is (IPGATE)
Your IP address is (IPADDR)
* End of Generic client script example

After the modem dials and connects, AS/400 reads the connection script. Each line
in the connection script causes AS/400 to send or receive data as follows:
1. Comment line.
2. AS/400 sends a blank followed by a carriage return to the remote system that
AS/400 called.

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3. AS/400 waits for the Username: prompt from the called system.
4. AS/400 sends the value specified in the configuration profile’s Remote service
access name field to the called system.
5. AS/400 waits for the Password: prompt from the called system.
6. AS/400 sends the value specified in the configuration profile’s Remote service
access password field to the called system.
7. AS/400 waits for the Protocol: prompt from the called system.
8. AS/400 sends the value slip to the called system to indicate that the SLIP
protocol will be used.
9. AS/400 waits for the The gateway address is prompt from the called system.
When this prompt is received, the next value received matches the (IPGATE)
keyword in the script. AS/400 uses this value as the IP address of the called
system for this point-to-point connection.
10. AS/400 waits for the Your IP address is prompt from the called system.
When this prompt is received, the next value received matches the (IPADDR)
keyword in the script. AS/400 uses this value as the local IP address of AS/400
for this point-to-point connection.
11. Comment line.

Creating SLIP Client (Dial-Out) Connection Scripts — Example: The following
example describes in detail how to create a client connection script to an Internet
Service Provider. The IBM Global Network is used as the ISP in the example.
When you open a new account with the IBM Global Network or with any ISP, the
ISP should provide you with either:
v A connection dialog example
v An actual connection dialog script
The connection dialog for the IBM Global Network looks like the following example:
&
****************************************
Welcome to the IBM Global Network
****************************************
Enter dial script version ==>
1.1
Gateway: IBMT2YA0 Port: 22
Select one of the following services:
INTERNET
Enter service ==>
INTERNET
Enter account userID password [\new_password] ==>
usinet barrier password
129.37.3.150 is your IP address.
129.37.1.10 is the Gateway IP address.
Begin TCP/IP communication now.

Use the keywords and rules for creating AS/400 connection scripts (shown in “Rules
for Creating and Changing Connection Scripts” on page 119) to convert the
connection dialog for IBM Global Network into a client connection script.
* IBM Global Network Client Script Example
& &
version ==>
& 1.1
service ==>
& INTERNET
password
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123

& (USERID) (PASSWORD)
(IPADDR) is your IP address.
(IPGATE) is the Gateway IP address.
ication now.
* End of IBM Global Network Client Script Example

Notice that this example differs from the supplied DIALIGN connection script in
Table 9 on page 121. This is because a connection script needs to contain only
sufficient text to allow AS/400 to locate and interpret the keywords and keyword
responses between the two hosts. You must carefully ensure that enough text
remains to maintain send/receive synchronization. The single word password and
the last partial line ication now. demonstrate this concept.
If you cannot obtain a connection dialog for the server any other way, do the
following:
1. Establish an interactive connection using a PC and copy down the dialog.
2. Use the dialog to create your client connection script.

Creating SLIP Server (Dial-In) Connection Scripts-Example
The following example is a server connection script for AS/400 to AS/400 SLIP
connections:
1.
2.
3.
4.
5.

* Server connection script example
(PROMPT)
& ENTER ACCOUNT/PASSWORD ==>
(USERID)/(PASSWORD)
& YOUR IP ADDRESS IS (IPADDR)

6. & (WAIT)’2’
7. & YOUR GATEWAY IP ADDRESS IS (IPGATE)
8. & BEGIN TCP/IP COMMUNICATION NOW
9. * End of Server connection script example
After the modem answers and connects, AS/400 reads the connection script. Each
line in the connection script causes AS/400 to send or receive data as follows:
1. Comment line.
2. Waits for any input from the client before beginning dialog.
3. Sends the prompt for account and password.
4. Waits for the user ID and password from the client.
5. Sends the IP address to be used by the client.
6. Waits 2 seconds before proceeding.
7. Sends the IP address of the server host to the client.
8. Sends confirmation of the client-to-server connection.
9. Comment line.

Connection Script Considerations for PPP
For PPP on an AS/400, you can use connection dialog scripts to perform the
following functions:
v Exchange sign-on and password information to authorize an AS/400 to connect
to a remote host or ISP

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v Exchange sign-on and password information to authorize a remote host to
connect to an AS/400
v Select the type of service requested (for example SLIP or PPP) from an ISP
Normally, all of these functions are performed when a PPP connection is negotiated
by AS/400. However, some ISPs may require user authorization or a type of service
selection prior to negotiating the PPP connection. Additionally, you will need to take
into account the following considerations:
v If a connection to or from an AS/400 is authenticated using a connection dialog
script, then the user ID and password that will be used is the one that was
specified in the connection profile for PAP validation. If the remote host does not
support validation when PPP is negotiated, then you must deactivate this
selection after you specify the PAP user ID and password.
v Connection validation with CHAP for PPP may also be requested after the initial
authentication. This is accomplished using the connection dialog script with a
different and more secure user ID and password.
v Any dynamic IP addresses that are exchanged during the connection dialog will
not be used by AS/400.

NLS Considerations
Once a SLIP connection is established, the application, such as TELNET or FTP,
that is running over the connection, must manage the ASCII to EBCDIC and
EBCDIC to ASCII translation.
If you are not using a connection script to establish a SLIP connection to or from a
remote system, then no other NLS considerations are necessary. If you are using a
connection script then it may be important to understand how AS/400 translates
connection scripts from EBCDIC to ASCII to be transmitted back and forth over the
connection.
Connection scripts on AS/400 are stored in EBCDIC format. However, most
systems that will connect to AS/400 are probably ASCII systems that will send their
connection script data in ASCII format. Therefore, AS/400 must translate the ASCII
data that is coming in to AS/400 over the connection from ASCII to EBCDIC.
AS/400 can then compare the connection script to the EBCDIC connection script
that is stored on AS/400.
Before AS/400 can send data to a remote system over the SLIP connection, AS/400
must translate the connection script data from EBCDIC to ASCII. The default
EBCDIC and ASCII CCSID values that AS/400 uses to translate connection scripts
are described below. The default values cover most needs, but you can change the
default values if you need support for other characters.
The default connection scripts that are shipped with AS/400 are located in members
in file QUSRSYS/QATOCPPSCR. See “Connection Dialog Scripts” on page 156 for
details on using connection scripts and for the member names.
This default connection script file, QATOCPPSCR, uses a CCSID of 500, which
means character set 697 and code page 500. Therefore, all character data in each
connection script member have a hex code point that this CCSID supports. AS/400
uses the EBCDIC CCSID value to translate connection script data when AS/400
sends the connection script data to or receives the connection script data from a
remote system.

Chapter 4. Configuring Point-to-Point TCP/IP (PPP and SLIP)

125

AS/400 obtains the ASCII CCSID from the TCP/IP point-to-point configuration profile
that is being used for the SLIP session. You can configure this value in the Script
source information section of the profile, which is shown in “Use Connection
Dialog Script” on page 145. The default ASCII CCSID value is 00819 (ISO 8859,
part1 Latin Alphabet No.1). This ASCII CCSID covers most 8-bit languages that use
character set 697. All of the code points that are defined for ASCII CCSID 00819
support translations to the EBCDIC CCSID 500. This default covers most
translations. However, if you must use characters that are not supported in EBCDIC
CCSID 500 and ASCII CCSID 00819, then you must do the following:
1. Change the ASCII CCSID defined in the TCP/IP point-to-point profile that you
plan to use to a value that supports all of the characters that you require.
2. Create a connection script file with a CCSID that supports all of the characters
that you require and that is compatible with the ASCII CCSID that you have
selected.
Create the new connection script file as follows:
v Create the file with the desired EBCDIC CCSID:
CRTSRCPF FILE(lib/file) MBR(*NONE)
RCDLEN(128) AUT(*USE)
CCSID(your_ccsid)

v Copy the default connection script file information into the new file:
CPYF FROMFILE(QUSRSYS/QATOCPPSCR)
TOFILE(lib/file) FROMMBR(*ALL)
TOMBR(*FROMMBR) MBROPT(*ADD)
FMTOPT(*MAP)

Notes:
a. If you use FMTOPT(*MAP), AS/400 database attempts to automatically
translate the CCSID 500 code points in the default connection script file to
the equivalent code points of the new CCSID in the new connection script
file.
b. If you do not want this automatic translation of data from CCSID 500 to your
new CCSID, then use FMTOPT(*NOCHK).
c. If you do not want to copy or use the default connection script members,
then omit the step for CPYF. The SCRSRCPF step will suffice.
The ASCII and EBCDIC CCSID values that you select must be compatible CCSIDs.
If the CCSIDs are not compatible, AS/400 issues message TCP8373 'Unable to
convert data from CCSID &1' to CCSID &2' and ends the SLIP session. See
National Language Support, SC41-5101 for information that can help you determine
which CCSID to use and which ASCII and EBCDIC CCSIDs are compatible.

Using SLIP with an Asynchronous Line Description
This section discusses how to create a SLIP connection profile that uses an
asynchronous line description.
Beginning in V4R2 support was added for the PPP line type. It is possible to create
a SLIP connection profile using either a PPP line description or an asynchronous
line description. While connection profiles using the older asynchronous line
description type can still be used, we strongly recommend that you use the new
PPP line type instead.

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You configure a SLIP connection profile using a PPP line description with
Operations Navigator. You configure SLIP over an asynchronous line description
using the CL command line interface.
See “Configuring SLIP Connection Profiles” on page 115 for working with a SLIP
connection profile that uses a PPP line description.
SLIP over an asynchronous line description uses the following four CL commands:
v
v
v
v

CFGTCPPTP - Configure Point-to-Point TCP/IP
ENDTCPPTP - End Point-to-Point TCP/IP
STRTCPPTP - Start Point-to-Point TCP/IP
WRKTCPPTP - Work with Point-to-Point TCP/IP

With these commands, you can start and end SLIP activity on AS/400. But more
importantly, you can create and use connection profiles and connection dialog
scripts.

Connection Dialog Scripts
Connection dialog scripts (or, simply, connection scripts) allow AS/400 and remote
systems to exchange sign-on and password information before a remote client may
connect to AS/400 system. Connection dialog scripts also allow you to authorize
users for connection, so that the system is protected from unwanted users.
Another common use of connection scripts is to dynamically assign an IP address
to the remote SLIP client. If you do not require these functions, you can bypass
script processing.
Other point-to-point protocols such as X.25 and frame relay, do not have connection
script support.

Configuring AS/400 Point-to-Point for SLIP
Before You Configure AS/400 for SLIP - Checklist
To create a SLIP connection profile that uses the older asynchronous line
description, you need the following:
An asynchronous line description on AS/400.
See “Step 1 - Configure an Asynchronous Line Description” on page 129 to
check for or create an asynchronous line description.
Your modem make and model, if you are using a modem. Also, make sure that
you have the owner’s manual for your modem.
See “Step 2 - Configure AS/400 For Your Modem” on page 130 to check for or
create a modem entry.
Information to complete your SLIP configuration profile.
See “Step 3 - Determine Configuration Profile Type” on page 132 to check for or
create various SLIP connection profiles.
There are other options you may choose to configure. See “Dial-In (*ANS)
Point-to-Point Profile Parameters” on page 140 and “Dial-Out Point-to-Point Profile
Parameters” on page 147 for details about the connection profiles.

Chapter 4. Configuring Point-to-Point TCP/IP (PPP and SLIP)

127

Hardware Requirements for the Asynchronous Line Description
To use the SLIP protocol, you must establish a serial asynchronous connection with
the remote system. To establish this connection, the appropriate adapters and I/O
Processor (IOP) that support serial (RS232) ports must be installed.
The following two families of adapters that can be used:
v You can use the I/O adapters listed below only with a SLIP connection that uses
an asynchronous line description. You cannot use these IOAs with the new PPP
line description.
– 2609 -- Two-line EIA 232/V.24 adapter
– 2612 -- One-line EIA 232/V.24 adapter
v You can use the I/O adapters listed below with either the PPP line description or
the asynchronous line description. These IOAs can be used with either PPP or
SLIP connections.
– 2699 -- Two Line WAN IOA
– 2720 -- PCI WAN/Twinaxial IOA
– 2721 -- PCI Two-Line WAN IOA
To find out what adapters are installed on your system, do this on the command
line:
===> go hardware

The Hardware Resources Display shown in Figure 83 is shown.
HARDWARE

Hardware Resources

System:

Select one of the following:
1.
2.
3.
4.
5.
6.
7.
8.

Work
Work
Work
Work
Work
Work
Work
Work

with
with
with
with
with
with
with
with

SYSNAM

communication resources
local workstation resources
storage resources
processor resources
token-ring LAN adapter resources
DDI LAN adapter resources
all LAN adapter resources
coupled system adapter

70. Related commands

Selection or command
===> 1
F3=Exit
F4=Prompt
F9=Retrieve
F12=Cancel
F16=AS/400 Main menu
(C) COPYRIGHT IBM CORP. 1980, 1996.

F13=Information Assistant

Figure 83. Hardware Display

Select option 1., to get the display shown in Figure 84 on page 129. Three 2609
communications adapters are configured on the 2623 communications processor.
Each 2609 adapter has two ports, to which you can attach modems.

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OS/400 TCP/IP Configuration and Reference V4R4

Work with Communication Resources
Type options, press Enter.
2=Edit
4=Remove
5=Work with configuration descriptions
Opt

Resource
CC02
LIN08
LIN081
LIN082
LIN05
LIN051
LIN052
LIN06
LIN061
LIN062
CMB01

F3=Exit
F5=Refresh
F12=Cancel

Type
2623
2609
2609
2609
2609
2609
2609
2609
2609
2609
2615

System:

SYSNAM

Text
Comm Processor
Comm Adapter
V.24 Port Enhanced
V.24 Port
Comm Adapter
V.24 Port Enhanced
V.24 Port
Comm Adapter
V.24 Port
V.24 Port
Combined function IOP

F6=Print

More...
F11=Display resource addresses/statuses

Figure 84. Hardware Support for SLIP-Example

Step 1 - Configure an Asynchronous Line Description
You must use the line description name when you add the dial-in or dial-out profile
for the line in “Step 3 - Determine Configuration Profile Type” on page 132.
To check for existing asynchronous line descriptions, enter the following:
WRKLIND LIND(*ASYNC)

If line descriptions exist, AS/400 displays them as shown in Figure 85 on page 130.
If no line descriptions exist, or if you prefer to create a new one, do either of the
following:
v Press F6=Create from the Work with Line Descriptions display.
v Enter the CRTLINASC on the command line and press F4, then F9.
Continue at “Asynchronous Line Description Parameters” on page 152. Then return
to “Step 2 - Configure AS/400 For Your Modem” on page 130.

Chapter 4. Configuring Point-to-Point TCP/IP (PPP and SLIP)

129

Work with Line Descriptions
Position to . . . . .

Starting characters

Type options, press Enter.
2=Change
3=Copy
4=Delete
5=Display
8=Work with status
9=Retrieve source
Opt
_
_
_
_
_
_

Line
ASCDIAL7
ASCNONSW4
ASCSWIT6
ASCSWIT7
MODEMLIN

Type
*ASYNC
*ASYNC
*ASYNC
*ASYNC
*ASYNC

6=Print

System:

SYSNAM

7=Rename

Text
Switched line to modem. DIALCMD(*OTHER)
Switched line to modem. DIALCMD(*OTHER)
Switched line to modem. DIALCMD(*OTHER)
Sample line to modem in this book

Parameters or command
===>
F3=Exit
F4=Prompt
F5=Refresh
F14=Work with status

Bottom
F6=Create

F9=Retrieve

F12=Cancel

Figure 85. Work with Asynchronous Line Descriptions

Step 2 - Configure AS/400 For Your Modem
Check to see if a sample configuration exists for your modem. Type CFGTCPPTP,
then select option 11 to view the default modem entries on AS/400. If your modem
is listed, go on to the next configuration step. If your modem is not listed, you can
do either of the following:
v Try the $generic hayes modem entry.
v Add an entry for your modem.
To determine which option is best, check the user manual for your modem. Look for
the following settings for command strings:
v Modem reset to factory defaults: This is often AT&F or AT&Z
v Modem initialization – Some of the options you should set are as follows:
– Display Verbal Result Codes: Often this is Q0 and V1
– Normal CD and DTR modes: Often this is &C1 and &D2
– Echo mode off: Often this is E0
– Data Set Ready (DSR) to follow Carrier Detect: Often, this is &S1
– Enable hardware flow control (RTS/CST)
– Enable error correction and optionally, compression
– Ensure DTE-DCE line speed is enabled to run at fixed 19.2K
– If the modem supports it, optionally enable the inactivity timer
v Modem answer mode:
– Answer after n rings: Often this option is S0=n
– Disconnect if no carrier (connection) after m seconds: Often this option is S7=m
v Modem dial type: This is usually ATDT, which selects tone dialing. To compare,
ATDP selects pulse dialing.

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If your modem and the $generic hayes modem entry match for these settings, then
you can most likely use the $generic hayes modem entry. If your modem supports
different command entries, then you should create a new modem entry.
Note: Although there is much consistency between AT-compatible modems, each
one often has unique settings. Therefore, be aware that these are
recommendations. Your modem user’s guide contains the details that you
need.
To add new modem information, enter option 1:
Work with Point-to-Point TCP/IP Modem Information
Type option, press Enter.
1=Add
2=Change
3=Copy

4=Remove

5=Display

Opt Name
1
My Modem
$generic hayes
GVC 28800
Hayes 14400 Accura
Hayes 28800 Accura
IBM 9600 7855
IBM 28800 7852-010
IBM 28800 7852-013
IBM 7852-400
IBM 7852-400 (2609 or 2612 EIA 232/V.24 adapter)
IBM 7857-017
MaxTech 28800
MultiTech 28800 Multimodem
USRobotics 14400 Sportster
USRobotics 28800 Sportster
F3=Exit

F5=Refresh

F9=Command line

F12=Cancel

6=Print
Source
DEFAULTS
DEFAULTS
DEFAULTS
DEFAULTS
DEFAULTS
DEFAULTS
DEFAULTS
DEFAULTS
DEFAULTS
DEFAULTS
DEFAULTS
DEFAULTS
DEFAULTS
DEFAULTS
MORE...
F17=Position to

Work with Point-to-Point TCP/IP Modem Information
Type option, press Enter.
1=Add
2=Change
3=Copy
Opt

4=Remove

5=Display

Name
ZOOM 14400
ZOOM 28800

6=Print
Source
DEFAULTS
DEFAULTS

Figure 86. Adding a Modem Entry-Display 1

Figure 87 on page 132 shows the default values that you get if you add modem
information for your modem. Change the defaults as needed.

Chapter 4. Configuring Point-to-Point TCP/IP (PPP and SLIP)

131

Add TCP/IP Point-to-Point Modem Information
Modem information name:
My Modem

Type changes, press Enter.
Modem initialization string
AT
Modem reset string
AT
Modem dial command
ATDT
Modem answer command
ATS0=2S7=30

F3=Exit

F12=Cancel

Figure 87. Adding a Modem Entry-Display 2

To add your own modem, you need the owner’s manual from the modem to
complete the prompts in this display.
Optionally, to add your own modem, copy the $generic hayes modem entry,
and change the prompt information to match the information required for
your modem.

The default modem answer command instructs the modem to answer an
incoming call after one ring and then wait a maximum of 30 seconds for a
connection. If you need more time to establish connections, you must
change this command.

Step 3 - Determine Configuration Profile Type
There are two kinds of connection profiles, *ANS and *DIAL profiles. Use *ANS
profiles for dial-in support. These profiles are called *ANS profiles because AS/400
uses them to answer incoming calls from remote systems.
Use *DIAL profiles for dial-out support. These profiles are called *DIAL profiles
because AS/400 uses them to dial out to remote systems.
For each modem attached to AS/400, you need at least one configuration profile.
For each line attached to the modem, you need an asynchronous line description.
If you are using the same modem to dial in and to dial out, you need two profiles
for that modem. You need a *ANS profile for dial-in support, and a *DIAL profile for
the dial-out support. If the modem has only one line attached, you need only one
line description.
Only one caller at a time can use a given asynchronous line and its associated line
description.
To add a dial-in profile, go to “Step 4 - Add a Dial-In (*ANS) Configuration Profile”
on page 133.

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OS/400 TCP/IP Configuration and Reference V4R4

To add a dial-out profile, go to “Step 5 - Add a Dial-Out (*DIAL) Configuration
Profile”.

Step 4 - Add a Dial-In (*ANS) Configuration Profile
Before you add a profile, have the following information ready:
The IP address this profile uses for the remote system that is connecting to this
AS/400 system.
The name of the *ASYNC line this connection will run over (from “Step 1 Configure an Asynchronous Line Description” on page 129).
Modem information, if you are going to use a modem. (from “Step 2 - Configure
AS/400 For Your Modem” on page 130).
The name of an authorization list, if you want to restrict use of the profile to a
specific group of users. See “System Access Authorization List” on page 146 for
details.
Other information is also required, depending on the choices you make when
configuring the profile. Review the information about the dial-in profile, in “Dial-In
(*ANS) Point-to-Point Profile Parameters” on page 140 to determine if you are ready
to add the profile.
To add a profile:
1. Choose Option 1 - Work with point-to-point TCP/IP from the Configure
Point-to-Point TCP/IP display.
2. Type 1 in the Opt column
3. Type a name for the profile
4. Type *ANS to add a dial-in profile

Step 5 - Add a Dial-Out (*DIAL) Configuration Profile
Dial-out connection profiles are called *DIAL profiles. You use them to dial out to
remote systems. Before you start entering information on the following displays, you
need to have some information ready. For example, write down the following:
The name of the *ASYNC line this connection will run over (from “Step 1 Configure an Asynchronous Line Description” on page 129).
Modem information, if you are going to use a modem. (from “Step 2 - Configure
AS/400 For Your Modem” on page 130).
The information for accessing the remote system, such as the modem telephone
number, a user ID, and a password. See “Remote System Access Information”
on page 152 for details.
Other information is also required, depending on the choices that you make when
you configure the profile. To help determine if you need more information for your
configuration profile, see the following:
v Figure 99 on page 147 contains a sample display for adding profile EEL.
v “Dial-Out Point-to-Point Profile Parameters” on page 147 contains information
about each parameter.
To add the profile:
1. Type 1 in the Opt column
Chapter 4. Configuring Point-to-Point TCP/IP (PPP and SLIP)

133

2. Type a name for the profile
3. Type *DIAL to create a dial-out profile

Step 6 - Start the Configuration Profile
Figure 88 shows a number of SLIP *DIAL profiles. Use the option 9=Start to start a
profile.
Work with Point-to-Point TCP/IP
Type option, press Enter.
1=Add
2=Change
3=Copy
4=Remove
9=Start
10=End
12=Work with line status

5=Display details
6=Print
14=Work with session job

Opt

Name

Mode

Type

Status

Line
Description

Line
Type

9__
___
___
___
___
___
___
___
___

MOLEANS1
NIMROD
PEBBLES
AS8TO7NSW
BAMBAM
DIALW31
IBMIGNSP
IBMIGNSP1
IBMIGNSP2

*ANS
*ANS
*ANS
*DIAL
*DIAL
*DIAL
*DIAL
*DIAL
*DIAL

*SLIP
*SLIP
*SLIP
*SLIP
*SLIP
*SLIP
*SLIP
*SLIP
*SLIP

INACTIVE
STRSSN
RINGW
INACTIVE
INACTIVE
INACTIVE
ACTIVE
INACTIVE
INACTIVE

ASCSWIT6
ASCSWIT4
ASCSWIT8
ASCNONSW3
ASCNONSW3
ASCSWIT5
ASCSWIT7
ASCSWIT7
ASCSWIT7

*ASYNC
*ASYNC QTPPANS021
*ASYNC QTPPANS020
*ASYNC
*ASYNC
*ASYNC QTPPDIAL90
*ASYNC QTPPDIAL93
*ASYNC QTPPDIAL83
*ASYNC QTPPDIAL89

F8=Work with modems
F11=Display text

Job
Name

More...
F9=Command line
F10=Local interface status
F12=Cancel
F14=Work with session jobs
F24=More keys

Figure 88. Work with Point-to-Point TCP/IP-Starting a SLIP Profile

Before you start a profile that is defined for a given line description, make sure that
the line description is not already being used by a different profile. Only one profile
at a time can use a given line.
When you start a profile by using option 9 from this display, you run the
STRTCPPTP command with its default settings. Other settings are available for
your use. For example, you may want to send an inquiry message that requires a
response before AS/400 releases the job. For example, use the inquiry message if
you are doing problem analysis and need to start the System Licensed Internal
Code (SLIC) component trace, tracing the ASCII device and controller. If AS/400 is
creating the device and controller names automatically at SLIP profile startup, you
need a way to pause the SLIP session job so you can display the object names. Or
you may want to keep the controller and device descriptions that AS/400 created
automatically, so that the jobs can be reused.

|
|
|
|
|
|
|
|
|
|

If your configuration profile does not start, you can print the script dialog that occurs
during start by specifying the *ERROR or *PRINT options on the STRTCPPTP
command. For information about using the *ERROR and *PRINT parameters, see
“Point-to-Point Jobs That Are Not Active” on page 139.

Monitoring Point-to-Point Activity
Use the Work with Point-to-Point TCP/IP (WRKTCPPTP) command to monitor and
manage SLIP activity.

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Options From WRKTCPPTP
Using Figure 89 as a reference, the following is a summary of selected
management tasks you can do from this display. This information is a supplement to
the information provided in the online help information for the various options. This
information is not intended to be a complete summary of the online text. Be sure
the profile that you want to change, copy, or remove is not active.
Work with Point-to-Point TCP/IP
Type option, press Enter.
1=Add
2=Change
3=Copy
4=Remove
9=Start
10=End
12=Work with line status

5=Display details
6=Print
14=Work with session job

Opt

Name

Mode

Type

Status

Line
Description

Line
Type

___
___
___
___
___
___
_14
___
___

MOLEANS1
NIMROD
PEBBLES
AS8TO7NSW
BAMBAM
DIALW31
IBMIGNSP
IBMIGNSP1
IBMIGNSP2

*ANS
*ANS
*ANS
*DIAL
*DIAL
*DIAL
*DIAL
*DIAL
*DIAL

*SLIP
*SLIP
*SLIP
*SLIP
*SLIP
*SLIP
*SLIP
*SLIP
*SLIP

INACTIVE
STRSSN
RINGW
INACTIVE
INACTIVE
INACTIVE
ACTIVE
INACTIVE
INACTIVE

ASCSWIT6
ASCSWIT4
ASCSWIT8
ASCNONSW3
ASCNONSW3
ASCSWIT5
ASCSWIT7
ASCSWIT7
ASCSWIT7

*ASYNC
*ASYNC QTPPANS021
*ASYNC QTPPANS020
*ASYNC
*ASYNC
*ASYNC QTPPDIAL90
*ASYNC QTPPDIAL93
*ASYNC QTPPDIAL83
*ASYNC QTPPDIAL89

F8=Work with modems
F11=Display text

Job
Name

More...
F9=Command line
F10=Local interface status
F12=Cancel
F14=Work with session jobs
F24=More keys

Figure 89. Work with Point-to-Point TCP/IP-Working With a Specific Job

Option 1 (Add)
Use this option to add a new configuration profile. See “Step 3 - Determine
Configuration Profile Type” on page 132 for information about the connection
profiles.
Option 2 (Change)
Use this option to change the information associated with a configuration profile
that is not active.
Option 3 (Copy)
Use this option to add a new profile that has the exact same characteristics as
the one being copied.
Option 4 (Remove)
Use this option to remove a configuration profile that is not active.
Option 5 (Display)
Use this option to display a configuration profile.
Option 6 (Print)
Use this option to print the same information about the configuration profile that
you see on the display when you select option 5.
Option 9 (Start)
Use this option to start a point-to-point session for a particular configuration
profile. This option calls the Start Point-to-Point TCP/IP (STRTCPPTP)
command with the name of the profile. If you enter the command and press
F4=Prompt, you can specify:
Chapter 4. Configuring Point-to-Point TCP/IP (PPP and SLIP)

135

v Which profile to start.
v Whether to capture any errors that occur while establishing the Point-to-Point
session.
v Whether to capture the complete connection script dialog in a spooled file.
F8 (Work with modems)
Displays the Work with TCP/IP Point-to-Point Modem Information display
(shown in Figure 86 on page 131).
F10 (Local interface status)
Displays the Work with TCP/IP Interface display. From this display you can
display information about particular interfaces and associated routes, start or
end a TCP/IP interface, or work with configuration status.
F14 (Work with session jobs)
Runs the Work with Active Jobs (WRKACTJOB) command for active jobs with
job names that start with the characters QTPP. This displays a list of any active
point-to-point TCP/IP jobs and allows you to work directly with these jobs. For
more information about managing jobs, see “Working With Point-to-Point Jobs”.

Working With Point-to-Point Jobs
SLIP jobs are Point-to-Point jobs that run in the QSYSWRK subsystem. In general,
you can work with the Point-to-Point jobs just as you work with any other jobs
running on AS/400. The Work Management book contains detailed information
about how to manage AS/400 jobs. You can work with individual SLIP jobs for
profiles that have a job name associated with them as seen on the WRKTCPPTP
display ( Figure 89 on page 135). To work with a job, select 14=Work with session
job. If you select option 14 against a profile that does not have a job associated
with it, such as MOLEANS1, AS/400 displays an error message.

Point-to-Point Job Names: The Point-to-Point job names for SLIP start with the
string QTPP, where dial-out jobs (*DIAL) are QTPPDIALnn, and Dial-In jobs (*ANS)
are QTPPANSnnn. The number string nn or nnn is a sequential number from 1 to 99
for *DIAL jobs and 1 to 999 for *ANS jobs. The AS/400 system starts a new job for
each SLIP profile that you start.
Point-to-Point Job Status Indicators: This topic summarizes the job status
indicators that Point-to-Point jobs can have. Some of the status indicators show you
what AS/400 is doing as a connection is starting, in use, or ending. Other status
indicators show error conditions. The jobs displayed in Figure 89 on page 135 show
some of the possible status indicators.
INACTIVE
No jobs are currently running for this profile. However, if a job is listed in under
Job Name on the Work with Point-to-Point TCP/IP display, you can display the
spooled file output for the job. To do this, select option 14 (Work with session
job). Option 14 runs the WRKJOB command for the configuration profile.
SBMERR
An error occurred during the submission of the job. If a SBMJOB fails (SLIP
status SBMERR), then no job name exists. The job name and job number are
generated if the SBMJOB actually completes and the job is added to the job
queue. If SBMERR occurs, look at the messages in the job log of the job that
ran the STRTCPPTP command to determine what caused the error.

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OS/400 TCP/IP Configuration and Reference V4R4

OUTQ
The connection has ended, and job information is available. Select option 14 to
display the job information.
JOBQ
A request to start the connection was submitted. The job is waiting on the job
queue.
STRSSN
A job is starting for this profile, but has not yet completed.
ENDSSN
The connection for this profile is ending.
JOBLOG
The connection for this profile has ended, and AS/400 is placing information in
the job log for this job.
ADDTCPCFG
TCP/IP interface address information is being added for the connection.
RMVTCPCFG
TCP/IP interface information is being removed from the connection.
MSGW
An inquiry message was sent to either the QTCP or to the QSYSOPR message
queue. Job connection processing is suspended until you respond to the inquiry
message.
SSNERR
An error occurred while the connection was established. To find out more about
the error, type option 14 next to the configuration profile name to run the
WRKJOB command.
STRTCPCMN
Starting TCP/IP communications. AS/400 is starting the SLIP protocol jobs.
ENDTCPCMN
Ending TCP/IP communications.
DIAL
AS/400 is calling the remote system to establish the connection.
RINGW
For a *ANS session that is waiting for someone to call.
CNNDIALOG
Connection dialog information is being exchanged over this connection.
ACTIVE
Connection has been made, and the job is running.
ICFERR
An error occurred during intersystem communications function (ICF)
communications. To find out more about the error, type option 14 next to the
configuration profile name to run the WRKJOB command.

Active Point-to-Point Jobs: Figure 90 on page 138 shows some active
point-to-point jobs that AS/400 displays when you do either of the following:
v Press F14 from the WRKTCPPTP display.
v Select option 2 from the Configure Point-to-Point TCP/IP display.

Chapter 4. Configuring Point-to-Point TCP/IP (PPP and SLIP)

137

To display the jobs, AS/400 runs the WRKACTJOB command. If no SLIP profiles
are started, AS/400 displays the following message:
No active jobs to display.

Work with Active Jobs
CPU %:

11.4

Elapsed time:

Type options, press Enter.
2=Change
3=Hold
4=End
8=Work with spooled files
Opt
__
__
__

Subsystem/Job User
QTPPANS020 QTCP
QTPPANS021 QTCP
QTPPDIAL93 QTCP

07:17:29

Active jobs:

5=Work with
6=Release
13=Disconnect ...
Type
BCH
BCH
BCH

CPU %
.0
.0
.0

7=Display message

Function
PGM-QTOCPPSM
PGM-QTOCPPSM
PGM-QTOCPPSM

Parameters or command
===>
F3=Exit
F5=Refresh
F10=Restart statistics
F12=Cancel
F23=More options
F24=More keys

Status
ICFW
RUN
ICFW

Bottom
F11=Display elapsed date

Figure 90. Work with Active Jobs-Displaying SLIP Jobs

Figure 91 shows the WRKJOB display for job QTPPDIAL93. For active
point-to-point jobs, option 10 from the WRKJOB display shows you the current job
log. You can use the job log to monitor the job while the job is running.
Work with Job
Job:

QTPPDIAL93

User:

QTCP

Number:

System:
009919

SYSNAM

Select one of the following:
1.
2.
3.
4.
10.
11.
12.
13.
14.
15.
16.

Display job status attributes
Display job definition attributes
Display job run attributes, if active
Work with spooled files
Display job log, if active or on job queue
Display call stack, if active
Work with locks, if active
Display library list, if active
Display open files, if active
Display file overrides, if active
Display commitment control status, if active

Selection or command
===> 10
F3=Exit

F4=Prompt

F9=Retrieve

Figure 91. Working with a Job

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OS/400 TCP/IP Configuration and Reference V4R4

F12=Cancel

More...

Point-to-Point Jobs That Are Not Active: To work with point-to-point jobs that
are not active, type option 14 next to the job in the Work with Point-to-Point
TCP/IP display. Then select option 4 from the WRKJOB menu to work with the
spooled file output from the job. The spooled file output includes a spooled file for
the job log and possibly a spooled file for the connection script dialog that occurred
between AS/400 and the remote system. AS/400 creates spooled file output for the
connection script dialog for connections that:
v Use a connection script, and
v Run with the output parameter on the STRTCPPTP command set to either of the
following:
– *ERROR (the default), and an error occurs during the connection dialog
between the local AS/400 system and the remote system.
– *PRINT, which puts the complete dialog into a spooled file.
Figure 93 on page 140 contains an example of a spooled file that contains
connection dialog.
Figure 92 shows the Work with Job Spooled Files (WRKSPLF) display. The display
results when you use option 4 from the WRKJOB display for a SLIP job that is not
active. In this case, job QTPPDIAL90, which is associated with SLIP profile
DIALW31, has two spooled files. You can display the output by using option 5
(Display).
Work with Job Spooled Files
Job:

QTPPDIAL90

User:

QTCP

Number:

Type options, press Enter.
1=Send
2=Change
3=Hold
4=Delete
5=Display
8=Attributes
9=Work with printing status
Opt
5
_

File
DIALW31
QPJOBLOG

Device or
Queue
PRT01
QEZJOBLOG

User Data
QTPPDIAL90
QTPPDIAL90

Status
RDY
RDY

Parameters for options 1, 2, 3 or command
===>
F3=Exit
F10=View 3
F11=View 2
F12=Cancel

Total
Pages
2
6

009524
6=Release
Current
Page

7=Messages

Copies
1
1

Bottom
F22=Printers

F24=More keys

Figure 92. Work with Job Spooled Files-Spooled Output for SLIP Jobs

The spooled file DIALW31 in Figure 92 is illustrated in Figure 93 on page 140.
v The leftmost column indicates the time a command, response, or informational
message was recorded.
v The next column from the left indicates the type of information that is recorded.
– === indicates that informational text follows
– ==> indicates outbound text follows
– <== indicates inbound text follows
Chapter 4. Configuring Point-to-Point TCP/IP (PPP and SLIP)

139

v The remaining text on a line is one of the following:
– Modem command or response
– Informational message
– Inbound or outbound text itself
Figure 93 shows an example of the information AS/400 places into the connection
dialog script spooled file output.
Display Spooled File
File . . . . . : DIALW31
Page/Line
Control . . . . .
Columns
Find . . . . . .
10:21:57 === Attempting modem reset.
10:21:57 ==> AT&FS0=0
10:21:57 === Reading modem response.
10:21:58 <==
10:21:58 <== OK
10:22:02 === Attempting modem initialization.
10:22:02 ==> AT&D2&C1X4V1Q0S7=70¬N6&K3%C1E0&S1
10:22:02 === Reading modem response.
10:22:02 <== AT&D2&C1X4V1Q0S7=70¬N6&K3%C1E0&S1
10:22:02 <== OK
10:22:06 === Attempting modem dial/answer.
10:22:06 ==> ATDT9,,752-4622
10:22:07 === Reading modem response.
10:22:12 === Reading modem response.
10:22:37 <==
10:22:37 <== CONNECT 19200/V42BIS
10:22:37 ==>
10:22:41 <== login:
10:22:41 ==> sliptest8
10:22:45 <== password:
10:22:45 ==> ********
10:22:45 === Establishing remote host connection.
10:27:08 === Remote host connection ended.

1/6
1 - 78

Figure 93. Work With Job Spooled Files-Spooled Output From a SLIP Job

You can use the connection script spooled file output to accomplish the following:
v Debug connection scripts.
v Ensure that the commands being sent to the modem are correct.
v Ensure that the expected modem responses are returned.

Dial-In (*ANS) Point-to-Point Profile Parameters
This topic provides explanations of the parameters available on the dial-in profile.
Enter CFGTCPPTP on the command line to get the display shown in Figure 94 on
page 141.

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OS/400 TCP/IP Configuration and Reference V4R4

Work with Point-to-Point TCP/IP
Type option, press Enter.
1=Add
2=Change
3=Copy
4=Remove
9=Start
10=End
12=Work with line status
Opt Name
1
EDITH

Mode
*ANS

Type

5=Display details
6=Print
14=Work with session job
Line
Description

Status

Line
Type

Job
Name

Figure 94. Add *ANS Configuration Profile for SLIP

Figure 95 shows the default entries you get when you first access the display.
Add TCP/IP Point-to-Point *ANS Profile
Name:
Text

EDITH

System:

SYSNAM

Type choices, press Enter.
TCP/IP information:
Protocol type . . . . . .
Local interface address .
Remote IP address . . . .
Maximum transmission unit
Allow proxy ARP . . . . .
Add default route . . . .

.
.
.
.
.
.

Physical line information:
Line description . . . .
Line type . . . . . . . .
Autocreate controller and
Remote location name .

. . . . .
. . . . :
device
. . . . .

F2=Change modem information
F12=Cancel

.
.
.
.
.
.

:
.
.
.
.
.

F3=Exit

*SLIP
576
N
N

*ASYNC
Y
F4=List

2
3
4
5
6

Address, F4 for list
Address
576-1006
Y=Yes, N=No
Y=Yes, N=No

Name

8
9

Y=Yes, N=No
Name
More...
F9=Command line

Figure 95. Creating a *ANS Configuration Profile-Display 1

Chapter 4. Configuring Point-to-Point TCP/IP (PPP and SLIP)

141

Add TCP/IP Point-to-Point *ANS Profile
Name:
Text

EDITH

System:

SYSNAM

Type choices, press Enter.
Modem information:
Use a modem . . . . . . . . . . . .
Modem information name
Script source information:
Use connection dialog script . .
Member . . . . . . . . . . . .
File . . . . . . . . . . . . .
Library . . . . . . . . . . .
ASCII character set identifier

F2=Change modem information
F12=Cancel

.
.
.
.

F3=Exit

Y=Yes, N=No
F4 for list

N
11
ANS400
QATOCPPSCR
QUSRSYS
00819

Y=Yes, N=No
Name
Name
Name
1-65533, *DFT

F4=List

More...

F9=Command line

Figure 96. Creating a *ANS Configuration Profile-Display 2

Add TCP/IP Point-to-Point *ANS Profile
Name:
Text

EDITH

System:

SYSNAM

Type choices, press Enter.
Local system security:
Allow IP datagram forwarding . . .
System access authorization list

F2=Change modem information
F12=Cancel

F3=Exit

N
*NONE

F4=List

12
13

F9=Command line

Figure 97. Creating a *ANS Configuration Profile-Display 3

Text:
1

Enter descriptive text for this configuration profile

Local Interface Address:
2

You can do one of the following:
v Enter a new interface address.
The new address can be:

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OS/400 TCP/IP Configuration and Reference V4R4

Y=Yes, N=No
*NONE, Name

Bottom

– A new interface address, or
– An interface address on the same network as an existing interface.
v Choose an existing address.
To find these existing addresses, press F4 (List) when the cursor is in
this field. Then select the interface you want to use.
Note: Using this option allows this AS/400 system to serve as a proxy
for ARP requests for the remote IP address of the system dialing
in.
For more information about proxy ARP, see “Allow Proxy ARP”.

Remote IP Address:
3

If you choose an existing interface address for the local interface address,
then AS/400 uses the remote interface address for TCP/IP communications
over the point-to-point connection. If you define a new local interface
address, then AS/400 uses the remote interface address only for routing to
the remote system.
If the remote system that is dialing in expects the IP address to be passed
back to it, then the remote system uses the remote address defined here as
its local interface address for the connection.
Note: If you choose to use proxy address resolution (ARP), then this
remote IP address must be on the same subnet as the local
interface address. See “Subnetworks and Subnet Masks” on page 6
for more information about subnets.

Maximum Transmission Unit:
4

This is the size in bytes of the largest packet that AS/400 can send over the
physical line that this interface uses. Ensure that the size of the MTU is no
larger than the maximum buffer size (MAXBUFFER) parameter that is
specified for the *ASYNC line you select for this *SLIP interface.

Allow Proxy ARP:
5

Select Y if you plan to use the local interface for proxy ARP. The local
interface must be an existing interface address.

Proxy ARP-Definition: Proxy ARP is a technique that allows one machine, the
proxy agent, to answer ARP requests that are actually destined for a different
machine. Proxy ARP is useful with SLIP because it allows a remote SLIP client to
logically appear to be part of a local network. This provides automatic connectivity
between the SLIP client and all hosts on a local network.
Proxy ARP-Example: Consider AS/400 with an IP address of 9.4.24.93, attached
to the 9.4.24 subnet. A remote workstation dials in to AS/400. AS/400 assigns an IP
address of 9.4.24.193. to the remote workstation. AS/400 sends data for 9.4.24.193
over the SLIP line. But to all other 9.4.24.x hosts on the local LAN, 9.4.24.193
appears to be attached to the local LAN. To send data to 9.4.24.193, the other
hosts send an ARP request to 9.4.24.193. SLIP connections do not support ARP.
Without proxy ARP, the remote workstation has no way to respond to the ARP
request. If AS/400 is configured to allow proxy ARP, AS/400 answers the ARP
request for 9.4.24.193. AS/400 receives the IP packet from the originating host, and
forwards the packet on over the SLIP connection to the remote client.
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143

If you want AS/400 to do this, set the Proxy ARP parameter (“Allow Proxy ARP” on
page 143 ) to Y.
Notes:
1. Only interface types that support ARP can be used with Proxy ARP. Interface
types that support ARP include token-ring, Ethernet, and FDDI. Point-to-point
interface types such as X.25 and *SLIP do not support ARP.
2. Proxy ARP does not mean proxy gateway. PCs connected directly to the LAN
cannot use AS/400 system as a gateway for Internet access through SLIP.
Be sure that the local interface is active before you start the configuration profile.
The start fails if the local interface is not active when you start the point-to-point
TCP/IP profile. To determine if the interface is active, type the following:
NETSTAT *IFC

Add Default Route:
6

Select Y to add a default route to the system. AS/400 adds the route when
the SLIP session is started. The local interface address specified in this
configuration profile is the next hop for the default route that is added.
Note: Only one default route can be active at a time. If you run the Start
Point-to-Point TCP/IP (STRTCPPTP) command for a configuration
profile that specifies Y to add a default route, and a default route is
already active, the session cannot start.
Use this option for *ANS profiles if you want to do the following:
v Connect two networks together and use a SLIP connection to do so
v Use an automatic default route to the other network
Otherwise, do not automatically add routes for your *ANS profiles.

Line Description:
7

Type the name of the line description to be used for this connection.
See “Step 1 - Configure an Asynchronous Line Description” on page 129 for
information about how to create or find the line description.

Autocreate Controller and Device:
8

Specify the default value of Y to have AS/400 automatically create the
controller and device descriptions for the line description specified in 7 (
“Line Description”). If you specify N, you must specify a remote location
name. See “Remote Location Name” on page 145.
Notes:
1. The setting for this parameter does not affect and is not affected by any
of the autoconfiguration system values (QAUTOCFG, QAUTORMT and
QAUTOVRT).
2. AS/400 creates controller and device descriptions only if they do not
already exist.
If Start Point-to-Point TCP/IP (STRTCPPTP) is issued with
AUTODLTCFG(*YES), then the controller and device description are
deleted when the point-to-point connection ends. The next time you
start a point-to-point connection using this profile the controller and
device descriptions are created again.

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OS/400 TCP/IP Configuration and Reference V4R4

However, if STRTCPPTP is issued with AUTODLTCFG(*NO), AS/400
does not delete the controller and device descriptions when the
connection ends. The next time the profile is used the previously
created controller and device descriptions are re-used.

Remote Location Name:
9

If Autocreate Controller and Device is N then this field must specify the
remote location name defined in the device description of the controller and
device description pair to use when Start Point-to-Point TCP/IP
(STRTCPPTP) is issued for this configuration profile. If Autocreate
Controller and Device is Y, then any name entered in this field is ignored.
Specify a value for this field only when using a specific controller and
device description pair that you created.
Notes:
1. The value specified is the same value specified for the Create
Asynchronous Device Description (CRTDEVASC) command
RMTLOCNAME parameter on the device description you want to use
when activating this point-to-point connection.
2. The controller and device description that you create must have status
VARIED ON prior to starting the TCP/IP point-to-point connection.
3. The TCP/IP point-to-point connection cannot start if the device
description is already in use.

Modem Information:
10

You must specify modem information if you are using a modem. For most
modems, you can select one of the entries that appears when you press
F4.
Note: You can change modem information by pressing F2 on the Add
TCP/IP Point-to-Point *ANS Profile display. If no modem
information is found, go to “Step 2 - Configure AS/400 For Your
Modem” on page 130.

Use Connection Dialog Script:
11

The remote system that is dialing in must provide the information required
by the server connection script. The remote system can do this by doing
either of the following:
v Using a matching connection script on its system.
v Providing the information interactively.
Note: Not all systems support the option to provide the information
interactively.
You determine whether a script is used by specifying Y or N on this
parameter. The most common use of scripts is to exchange sign-on and
password information before a remote client may connect to AS/400
system. Another common use is to dynamically assign an IP address to the
remote SLIP client. See “NLS Considerations” on page 125 for information
about the ASCII character set identifier used in scripts.

Allow IP Datagram Forwarding:

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145

Use IP datagram forwarding to forward IP datagrams that come from a
remote host, but are not meant for the local IP address.
The default is N (No). Datagrams from the remote system that are not
destined for this address are discarded.
Note: You can disable datagram forwarding for all TCP/IP interfaces on this
system by using the command CHGTCPA IPDTGFWD(*NO). When
you do this, the value set in configuration profiles is ignored, and no
IP datagrams are forwarded. Once a remote system is connected to
AS/400 and the user signs on to AS/400 using TELNET or FTP, then
the user can access the other systems in the network that is
connected to this AS/400 system. The user has access because the
interface address for the user is now from this AS/400 system and
not from the original remote client.
To determine the current value for system datagram forwarding, enter
CHGTCPA and press F4. The AS/400 prompter will show the current value
for the parameter.
For information about security for AS/400 support of the SLIP protocol, see
the Tips and Tools for Securing Your AS/400 book.

PING-ing your local IP address: After establishing a point-to-point connection
with a remote system, it is typical to try to PING both the remote and local IP
addresses defined for the connection. This is done to ensure the connection to the
remote system is actually operational. If the connection is complete, the PING to
the remote IP address should complete successfully. However, a PING to your local
IP address may or may not work, depending on whether the remote system
forwards IP datagrams or not.
When a PING is done on a local IP address for point-to-point links such as SLIP,
X.25, and so on, the PING ECHO request will actually leave the local system and
travel to the remote system. The remote system will then look at the PING ECHO
request and determine that the PING address is not its own. If the remote system is
capable of forwarding IP datagrams, it will resend the PING ECHO request back out
over the point-to-point link to the local system. When the local system receives the
PING ECHO request, it determines that the PING address is its own and replies
back with a PING ECHO reply completing the PING request. However, if the remote
system does not do IP datagram forwarding, then a PING of your local IP address
will not work since the PING ECHO request will be thrown out.
PING time metrics will normally show that a PING to the local IP address takes
twice as long to complete as a PING to the remote IP address because all PING
requests to the local address have to travel through the remote system first.

System Access Authorization List:
13

Enter the name of an AS/400 authorization list if you want to allow only the
user profiles that are specified in the authorization list to connect to this
AS/400 from a remote system over SLIP.
Note: If ’Use connection dialog script’ (see “Use Connection Dialog Script”
on page 145) is set to N (No), you must set the system access
authorization list to *NONE. Authorization list checking is only done
as part of a connection dialog script.

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OS/400 TCP/IP Configuration and Reference V4R4

Use the Create Authorization List (CRTAUTL) command to create an
authorization list. Use the Add Authorization List Entry (ADDAUTLE)
command to add user profile entries to the list.
For more information about how and when to use authorization lists, see
the Tips and Tools for Securing Your AS/400 book.

Dial-Out Point-to-Point Profile Parameters: To create a dial-out (*DIAL) profile,
enter WRKTCPPTP. AS/400 displays the Work with Point-to-Point TCP/IP display
shown in Figure 98. Enter the following:
1. Option 1 to add a profile.
2. A name for the profile.
3. *DIAL for a dial-out profile.

Work with Point-to-Point TCP/IP
Type option, press Enter.
1=Add
2=Change
3=Copy
4=Remove
9=Start
10=End
12=Work with line status
Opt Name
1
EEL

Mode
*DIAL

Type

5=Display details
6=Print
14=Work with session job
Line
Description

Status

Line
Type

Job
Name

Figure 98. Add *DIAL Configuration Profile for SLIP

Figure 99, Figure 100, Figure 101, and Figure 102 show the default entries that
AS/400 displays for adding a *DIAL profile.
Add TCP/IP Point-to-Point *DIAL Profile
Name:
Text

EEL

System:

SYSNAM

Type choices, press Enter.
TCP/IP information:
Protocol type . . . . . . .
Local interface address . .
Remote IP address . . . . .
Request header compression
Maximum transmission unit .
Add default route . . . . .
Additional name server . .

F2=Change modem information
F12=Cancel

.
.
.
.
.
.
.

:
.
.
.
.
.
.

F3=Exit

*SLIP
Y
576
N
*NONE

F4=List

1
2
3
4
5
6

Address, *DYNAMIC
Address, *DYNAMIC
Y=Yes, N=No
576-1006
Y=Yes, N=No
Address, *NONE

F9=Command line

More...

Figure 99. Creating a *DIAL Configuration Profile-Display 1

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147

Add TCP/IP Point-to-Point *DIAL Profile
Name:
Text

System:

EEL

SYSNAM

Type choices, press Enter.
Physical line information:
Line description . . . .
Line type . . . . . . . .
Autocreate controller and
Remote location name .

. . . . .
. . . . :
device
. . . . .

Modem information:
Use a modem . . . . . . . . . . . .
Modem information name

F2=Change modem information
F12=Cancel

F3=Exit

*ASYNC
Y

F4=List

Name

8
9

Y=Yes, N=No
Name

Y=Yes, N=No
F4 for list

More...

F9=Command line

Figure 100. Creating a *DIAL Configuration Profile-Display 2

Add TCP/IP Point-to-Point *DIAL Profile
Name:
Text

EEL

System:

SYSNAM

Type choices, press Enter.
Script source information:
Use connection dialog script . .
Member . . . . . . . . . . . .
File . . . . . . . . . . . . .
Library . . . . . . . . . . .
ASCII character set identifier

F2=Change modem information
F12=Cancel

.
.
.
.

F3=Exit

11
N
DIAL400
QATOCPPSCR
QUSRSYS
00819

F4=List

Y=Yes, N=No
Name
Name
Name
1-65533, *DFT

F9=Command line

Figure 101. Creating a *DIAL Configuration Profile-Display 3

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OS/400 TCP/IP Configuration and Reference V4R4

More...

Add TCP/IP Point-to-Point *DIAL Profile
Name:
Text

EEL

System:

SYSNAM

Type choices, press Enter.
12

Remote system access information:
Remote service phone number
*NONE
Remote service access name
*NONE
Remote service access password
*NONE

F2=Change modem information
F12=Cancel

F3=Exit

F4=List

F9=Command line

Bottom

Figure 102. Creating a *DIAL Configuration Profile-Display 4

Local Interface Address:
1

This address is the local interface address to be used by this AS/400 for
point-to-point communications.
You can do one of the following:
v Enter a new interface address.
v Enter a new interface address on the same network as an existing
interface when you want to tie two AS/400 systems together.
v Choose *DYNAMIC.
Use the special value *DYNAMIC when the remote system specifies a
local interface address for your system. If you specify *DYNAMIC, you
must use a connection dialog script. Both the connection dialog script
and the remote system must support IP address passing.

Remote IP Address:
2

Enter the IP address of the remote system for this profile. This address is
the local interface address on the remote system.
Specify *DYNAMIC to allow the remote address to be determined
dynamically. You need this special value when the remote system specifies
a remote IP address for your system.
Note: *DYNAMIC requires use of a connection dialog script.

Request Header Compression:
3

The default, Y, indicates this system compresses header information when it
establishes the point-to-point connection. If the remote system does not
support the header compression, which is called Van Jacobson (VJ) header

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149

compression, 1 AS/400 establishes a session that does not use header
compression. Therefore, you should not need to change this value.
Using header compression improves the performance of the serial line,
which is usually slow anyway.

Maximum Transmission Unit:
4

The maximum transmission unit (MTU) is the size in bytes of the largest
packet that is to be sent over the physical line that this interface uses.
Note: The MTU size cannot be larger than the maximum buffer size
(MAXBUFFER) on the *ASYNC line description that this *SLIP
interface uses.

Add Default Route:
5

If you change this value to Y (Yes), AS/400 adds a default route to the
remote system when the session is started. The local interface address
specified in this configuration profile becomes the next hop for the default
route that is added. Turn this option off when you know to which host this
AS/400 system will connect.
Note: There can be only one active default route. If the Start Point-to-Point
TCP/IP (STRTCPPTP) command is issued for a configuration profile
that specifies Y for Add default route field, and a default route is
already active, the session cannot start.

Additional Name Server:
6

Enter the IP address of a name server that is accessed through the
point-to-point connection to the remote system.
If you specify a name server address, AS/400 adds the name server
address to the end of any existing list of name servers when this
configuration profile is started. This field is valid only for *DIAL point-to-point
TCP/IP profiles.
If you use an ISP to connect to the Internet, you may receive a name
server address from the ISP. Then when you connect, you can use host
names instead of IP addresses for remote sites.
If you add an additional name server for this connection, then you must fully
qualify any host names on this connection. Otherwise, the domain of your
local AS/400 is appended to the unqualified host name. If this occurs, the
additional name server cannot find the host entry.
Note: There can only be one active point-to-point session with an
additional name server address defined. If the Start Point-to-Point
TCP/IP (STRTCPPTP) command is issued for a profile that specifies
Y for the Additional Nameserver field, and a point-to-point profile is
already active with an additional name server address, the session
cannot start. The default value for this field is *NONE. The list of
name servers is not changed.
This name server provides limited support when connecting to a remote
network. Most sockets applications that were activated prior to establishing

1. SLIP support with header compression is also called CSLIP, or Compressed Serial Line Internet Protocol.

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OS/400 TCP/IP Configuration and Reference V4R4

the *DIAL connection to a remote system will not see this name server
unless they are ended and restarted. In particular, you will need to restart
SMTP after establishing a remote connection in order to use a name server
that has been dynamically added.

Line Description:
7

Autocreate Controller and Device:
8

Specify the default value of Y to have AS/400 automatically create the
controller and device descriptions for the line description specified in 7
(“Line Description”). If you specify N, you must specify a remote location
name (see “Remote Location Name”).
Notes:
1. The setting for this parameter does not affect and is not affected by any
of the autoconfiguration system values (QAUTOCFG, QAUTORMT and
QAUTOVRT).
2. AS/400 creates controller and device descriptions only if they do not
already exist.
If Start Point-to-Point TCP/IP (STRTCPPTP) is issued with
AUTODLTCFG(*YES), then when the point-to-point connection ends the
controller and device description are deleted. The next time you start a
point-to-point connection using this profile the controller and device
descriptions are created again.
However, if STRTCPPTP is issued with AUTODLTCFG(*NO), AS/400
does not delete the controller and device descriptions when the
connection ends. The next time the profile is used the previously
created controller and device descriptions are re-used.

Remote Location Name:
9

Modem Information:

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151

You must specify modem information if you are using a modem. For most
modems, you can select one of the entries that appears when you press
F4.
If your modem does not appear in the list, go to “Step 2 - Configure AS/400
For Your Modem” on page 130.

Script Source Information:
11

You determine whether a connection script is to be used by specifying Y or
N. If you specify Y, the remote system that is dialing in must provide the
information required by the server connection script that you specify. The
remote system can do this by either of the following:
v Using a matching connection script on its system.
v Providing the information interactively.
Note: Not all systems support the option to provide the information
interactively.
The most common uses of scripts are for exchanging sign-on and password
information before permitting the remote client to connect to AS/400 system.
Another common use is to dynamically assign an IP address to the remote
SLIP client. If you do not require these functions, you can bypass script
processing.
For information about the ASCII character set identifier, see “NLS
Considerations” on page 125.
For examples of scripts, see “Connection Dialog Scripts” on page 156.

Remote System Access Information:
12

The remote system access information consists of the following:
v The remote service telephone number.
v The remote service access name.
v The remote service access password.
The remote service telephone number is the number that the modem calls
to contact the remote system. Use the remote service access name to
provide a user ID when the remote system requires this information before
allowing you to connect. If the remote system requires an account name in
addition to the user ID, then enter both values into the Remote service
access name field, separated by a blank as follows:
account userID

Use the remote service access password when the remote system also
requires you to provide a valid password for the user ID or account name.
If the remote system requires a user ID and password information, then you
must use a connection script and include the user ID and PASSWORD
keywords.
For examples of scripts, see “Connection Dialog Scripts” on page 156.

Asynchronous Line Description Parameters: There are many parameters for
AS/400 Create Line Description Asynchronous (CRTLINASC) command. This topic

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OS/400 TCP/IP Configuration and Reference V4R4

describes the parameters that you must specify to use an asynchronous line
description with AS/400 TCP/IP point-to-point configuration profiles. This topic also
discusses parameters and parameter values that differ from the command defaults.
For more information about the parameters options for the CRTLINASC command,
see the Communications Configuration book.
Two examples of commands to create asynchronous line descriptions follow. The
line MODEMLIN using resource LIN011 is an example for a line that is connected to
a modem. The line description NOMODEMLIN using resource LIN022 is an
example of a direct connection. That is, the physical line for NOMODEMLIN is
directly connected to the remote system through a null modem adapter.

CRTLINASC Parameters When Using a Modem: The following topic discusses a
command that was used to create an asynchronous line description that is named
MODEMLIN. MODEMLIN uses resource LIN011. It was created to be used with
AS/400 point-to-point TCP/IP. Figure 103 on page 155 shows the parameters that
you should use for an asynchronous line that is attached to a modem.
CRTLINASC

LIND(MODEMLIN)
LINESPEED(19200)
CNN(*SWTPP)
SWTCNN(*DIAL)
AUTODIAL(*YES)

RSRCNAME(LIN011)
MAXBUFFER(1500)
DIALCMD(*OTHER)
AUTOANS(*NO)
INACTTMR(*NOMAX)

LIND(MODEMLIN)
The name of the line description- you specify this name in any AS/400 TCP/IP
point-to-point configuration profile that uses this line.
RSRCNAME(LIN011)
The unique name that is assigned by AS/400 to identify the physical
communications port attached to your system. This example uses LIN011 as
the name AS/400 has associated with the communications port. For information
about how to determine the resource name you need, see “Hardware
Requirements for the Asynchronous Line Description” on page 128.
LINESPEED(19200)
The line speed of the asynchronous line in bits per second (bps). If your
modem supports data rate conversion, you should be able to use line speed
19200. Most modems that support error correction also support data rate
conversion. If your modem does not support data rate conversion, then the
asynchronous line speed must match the rate that the modem connects to the
remote system.
Note: The 19,200 line speed is used for illustration here because this value
can be specified on any AS/400 system using any adapter and IOP
combination. If both your modem and AS/400 hardware support a higher
line speed, use this value instead.
See “Step 2 - Configure AS/400 For Your Modem” on page 130 for more
information on configuring your modem.
MAXBUFFER(1500)
The maximum size of any single data packet sent across the line. This value
must always be at least as large as the value specified for the Maximum
Transmission Unit (MTU) in any TCP/IP point-to-point profile that uses this line.
Note: The value MAXBUFFER(1500) is used in this example because the
value 1500 is larger than any MTU value that could be specified in a
TCP/IP point-to-point configuration profile.
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153

CNN(*SWTPP)
Specifies that this is a switched point-to-point asynchronous line. The line
description must be specified as a switched line when using a modem.
DIALCMD(*OTHER)
Specifies that this asynchronous line is attached to a modem that uses the
Hayes AT command set. Only AT command modems are supported for use with
AS/400 TCP/IP point-to-point connection profiles. You must use this value if
SLIP is to use the asynchronous line.
SWTCNN(*DIAL)
You must specify this value when you specify DIALCMD(*OTHER).
Note: Do not confuse the value specified for SWTCNN with the operating
mode of your configuration profile. It does not matter whether line
description will be used with an operating mode *DIAL configuration
profile or a *ANS profile. You must always specify SWTCNN(*DIAL) for
the line.
AUTOANS(*NO)
Specifies that the support in AS/400 line description for automatic answering is
not used. You must specify this value when you specify SWTCNN(*DIAL).
Note: AS/400 TCP/IP Point-to-Point uses the Auto Answer Mode capability of
your modem to answer incoming calls to an *ANS Operating Mode
configuration profile. AUTOANS(*NO) does not affect the ability of
AS/400 SLIP to respond to an incoming call.
AUTODIAL(*YES)
You must specify this value when you specify DIALCMD(*OTHER).
INACTTMR(*NOMAX)
You must specify this value when you specify DIALCMD(*OTHER).

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OS/400 TCP/IP Configuration and Reference V4R4

Create Line Desc (Async) (CRTLINASC)
Type choices, press Enter.
Line description . . . .
Resource name . . . . .
Online at IPL . . . . .
Physical interface . . .
Connection type . . . .
Switched network backup
Vary on wait . . . . . .
Autocall unit . . . . .
Data bits per character
Type of parity . . . . .
Stop bits . . . . . . .
Duplex . . . . . . . . .
Echo support . . . . . .
Line speed . . . . . . .
Modem type supported . .
Switched connection type
F3=Exit
F4=Prompt
F24=More keys

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

F5=Refresh

LIND
>
RSRCNAME
>
ONLINE
INTERFACE
CNN> *SWTPP
SNBU
VRYWAIT
AUTOCALL
BITSCHAR
PARITY
STOPBITS
DUPLEX
ECHO
LINESPEED
>
MODEM
SWTCNN> *DIAL
F12=Cancel

MODEMLIN
LIN011
*YES
*RS232V24
*NO
*NOWAIT
*NO
8
*NONE
1
*FULL
*NONE
19200
*NORMAL
More...
F13=How to use this display

Create Line Desc (Async) (CRTLINASC)
Type choices, press Enter.
Autoanswer . . . . . . . . . . . AUTOANS> *NO
Autodial . . . . . . . . . . . . AUTODIAL> *YES
Dial command type . . . . . . . DIALCMD> *OTHER
Autocall resource name . . . . . ACRSRCNAME
Calling number . . . . . . . . . CALLNBR
*NONE
Inactivity timer . . . . . . . . INACTTMR> *NOMAX
Maximum buffer size . . . . . . MAXBUFFER
> 1500
Flow control . . . . . . . . . . FLOWCNTL
*NO
XON character . . . . . . . . . XONCHAR
11
XOFF character . . . . . . . . . XOFFCHAR
13
End-of-Record table:
EORTBL
End-of-Record character . . .
00
Trailing characters . . . . .
0
+ for more values

Figure 103. Creating an Asynchronous Line Description for a Line With a Modem-Example

CRTLINASC Parameters For a Direct Connection: This topic provides a sample
asynchronous line description for a direct connection. The line description name is
NOMODEMLIN. NOMODEMLIN uses resource LIN022. It was created to be used
with AS/400 point-to-point TCP/IP. This example assumes that asynchronous ports
of AS/400 and the remote system are directly connected through a NULL modem
adapter.
CRTLINASC LIND(NOMODEMLIN)
LINESPEED(19200)
CNN(*NONSWTPP)

RSRCNAME(LIN022)
MAXBUFFER(1500)

LIND(NOMODEMLIN)
The name of the line description- you specify this name in any AS/400 TCP/IP
point-to-point configuration profile that uses this line.
RSRCNAME(LIN022)
The unique name that AS/400 has assigned to identify the physical
communications port attached to your system. This example uses LIN022 is the

Chapter 4. Configuring Point-to-Point TCP/IP (PPP and SLIP)

155

name AS/400 has assigned to the communications port. To determine the
resource name you need, see “Hardware Requirements for the Asynchronous
Line Description” on page 128.
LINESPEED(19200)
The line speed of the asynchronous line in bits per second (bps). The line
speed you specify must be compatible with the modem attached to the line. In
this example, the line speed is set to 19,200 bps.
Note: When using a direct connection, both systems must specify the same
value for the line speed.
MAXBUFFER(1500)
The maximum size of any single data packet sent across the line. This value
must always be at least as large as the value specified for the Maximum
Transmission Unit (MTU) in any TCP/IP point-to-point profile that uses this line.
Note: The value MAXBUFFER(1500) is used in this example because the
value 1500 is larger than any MTU value that could be specified in a
TCP/IP point-to-point configuration profile.
CNN(*NONSWTPP)
Specifies that this is a non-switched point-to-point asynchronous line. The line
description must be specified as a non-switched line when two systems are
directly connected with a NULL modem adapter.

Connection Dialog Scripts: To control whether AS/400 uses a connection script,
you configure the Use connection dialog script field on the point-to-point
configuration profile. Valid values for this field are:
N

No login sequence is required beyond the physical modem connection.

A connection dialog script is required. Each connection script contains a
text template that outlines the exchange of authorization and connection
parameters with a remote host.

Security: For information about security for AS/400 support of the SLIP protocol,
see the Tips and Tools for Securing Your AS/400 book.

PPP/SLIP over *PPP
You must use the Operations Navigator to configure and administer PPP and
SLIP profiles using a *PPP linetype.
If you use the command line interface to control Dial-in and Dial-out operations,
you can still use these functions:

|
|
|
|
|

v STRTCPPTP to START *PPP profiles
v ENDTCPPTP to END *PPP profiles
v
v
v
v
v

|
|
|
|

156

WRKTCPPTP to Work with *PPP profiles, but only in a limited capacity:
9 (Start)
10 (End)
12 (Work with line status)
14 (Work with session job)

OS/400 TCP/IP Configuration and Reference V4R4

|
|

Note: You can perform these panel options only by using AS/400 Operations
Navigator: 2 (Change), 3 (Copy), 4 (Remove), and 5 (Display details).

|
|
|

Basically, you can control the operational aspects of PPP from the command line
interface, but for configuration tasks that are PPP specific, you need to use
Operations Navigator.
Work with Point-to-Point TCP/IP
Type option, press Enter.
1=Add
2=Change
3=Copy
4=Remove
5=Display details
12=Work with line status
14=Work with session job

9=Start

10=End

Opt

Name

Mode

Type

Status

Line
Description

Line
Type

___
___
___
___
___
___
___
___

______
BAMBAM
BARNEY
BETTY
DINO
PEBBLES
FRED
WILMA

____
*ANS
*ANS
*ANS
*ANS
*ANS
*DIAL
*DIAL

*SLIP
*SLIP
*PPP
*PPP
*SLIP
*SLIP
*PPP

STRSSN
ACTIVE
INACTIVE
OUTQ
CALLW
INACTIVE
ACTIVE

ANSWERIT4
ANSWERIT1
ANSWERIT2
ANSWERIT5
ANSWERIT3
DIALOMATIC
ALTDIAL

*ASYNC QTPPANS002
*ASYNC QTPPANS001
*PPP
QTPPANS003
*PPP
QTPPANS010
*PPP
QTPPANS004
*ASYNC
*PPP
QTPPDIAL01

F3=Exit
F5=Refresh
F11=Display status

Job
Name

Bottom
F9=Command line
F10=Local interface status
F12=Cancel
F14=Work with session jobs
F24=More keys

Figure 104. Sample Work with Point-to-point TCP/IP panel with *PPP profiles

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157

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OS/400 TCP/IP Configuration and Reference V4R4

Chapter 5. Telnet Client
|
|
|
|

Important note: A thorough and in-depth explanation of Telnet is beyond the scope
and purpose of this document. The majority of material on the Telnet client
application is covered in the AS/400e Information Center under the TCP/IP topic.
For more information see “TCP/IP Topics in the Information Center” on page xv.

|
|

The topics that remain in this chapter include conceptual and reference information
on the Telnet client 3270 and VTxxx full-screen modes.

5250 Full-Screen Mode Considerations
This material is covered in the AS/400e Information Center under the TCP/IP
topic. For more information see “TCP/IP Topics in the Information Center” on
page xv.

|
|
|

TN5250—Start TCP/IP Telnet Command
The following optional parameters on the STRTCPTELN or Telnet command are
applicable during a 5250 full-screen mode session:
v Timeout wait for host (INZWAIT)
v Keyboard language type (KBDTYPE) (See “TN3270 or TN5250—Specifying
Keyboard and Character Sets” on page 160)
v Port number of the remote host server application (PORT)

TN5250—Screen Size
Telnet 5250 full-screen mode supports the following screen sizes:
v 1920-character (24 x 80) on all 5250 display stations.
v 3564-character (27 x 132) on 3180 Model 2; 3197 Models D1, D2, W1, W2; and
3477 Models FA, FC, FD, FE, FG, FW.

3270 Full-Screen Mode Considerations
The 3270 full-screen mode is activated by negotiating 327x workstation support with
the remote Telnet server application. A typical example of a Telnet client 3270 mode
environment is shown in Figure 105.
AS/400 System

Display
Device

Physical
Device
Description

IBM or Other System
TELNET
Client
Support

TCP/IP

TELNET
3270
Server
Support

RV3H025-0

Figure 105. Typical Telnet 3270 Mode Environment (Telnet Client)

3270 full-screen support is negotiated with any Telnet server application that
supports 3270 full-screen (rather than 5250) applications. An example of such a
© Copyright IBM Corp. 1997, 1999

159

system is the System/370 or System/390* system. All workstation types are
negotiated to the 3278 Model 2 workstation when Telnet is in 3270 full-screen
mode. The exceptions to this rule are:
v Remote 3277 workstations are negotiated as a 3277 Model 2
v Remote 3279 workstations are negotiated as a 3279 Model 2
When the Telnet session is started, your display station is controlled by the remote
system application. You receive the same displays and enter data in the same way
that you do for other 3270 devices attached to the remote system.

TN3270—Start TCP/IP Telnet Command
The following optional parameters on the STRTCPTELN or Telnet command are
applicable during a 3270 full-screen mode session:
v Keyboard language type (KBDTYPE) (See “TN3270 or TN5250—Specifying
Keyboard and Character Sets”)
v Page up (roll down) key (PAGEUP)
v Page down (roll up) key (PAGEDOWN)
v Cursor select key (CSRSLT)
v Outgoing 3270 translation table (TBL3270OUT)
v Incoming 3270 translation table (TBL3270IN)
v Timeout wait for host (INZWAIT)
v Numeric lock keyboard (NUMLCK)
v Change how nulls are handled (NULLS)

Using a Display Station during Telnet 3270 Full-Screen Mode
When using a display station during a Telnet 3270 full-screen session, you should
be aware of keyboard and display differences. Other special considerations for
Telnet 3270 mode include number of input fields, error messages, and ending a
session.

TN3270 or TN5250—Specifying Keyboard and Character Sets
The keyboard language type you specify for your work station, using the keyboard
language type parameter on the STRTCPTELN command, must be the same as
the keyboard language type parameter of the remotely attached workstation. If you
specify a keyboard language type that does not match, some of the characters are
not displayed as expected.
For a description of different keyboard language types, see the Local Device
Configuration book.

5250 and 3270 Keyboards
The placement and function of keys is different on the 5250 keyboard (3196G, 3180
Model 2, or 5291) than on the 3278 keyboard. Differences between these
keyboards are shown in the 3270 Device Emulation Support book.
Note: For the Telnet client operating in a 3270 full-screen mode, the 3270 Clear
function defaults to the key sequence Shift-Cmd-Backspace.

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OS/400 TCP/IP Configuration and Reference V4R4

Keyboard differences for the following keyboards are shown in the System
Operation for New Users book.
v IBM-enhanced keyboard
v 122-key typewriter keyboard
v 5250 keyboard
v Personal computer or personal computer AT style keyboard
v Personal computer or personal computer AT 5250 style keyboard
v IBM-enhanced personal computer keyboard

Personal Computer Keyboards
If your personal computer uses the Client Access Workstation Function (WSF), you
can display the layout of your 5250 keyboard using the Work Station Function Keys
(WSFKEYS) command. You can alter the style using the Configure Work Station
Function (CFGWSF) command. These commands are discussed in the Client
Access/400 for DOS with Extended Memory Setup book. If your personal computer
does not use the workstation function, refer to the appropriate documentation for
your emulator (for example, OS/2 CM/2) to view or change the keyboard style.

TN3270—Minus Sign
If you specified the value *YES for the numeric lock keyboard parameter of the
STRTCPTELN command, if you are using a data entry keyboard, and if the cursor
is located in a numeric-only field, then do the following to display a minus sign.
To display a 5250 minus sign:
1. Press the Num (Numeric) key.
2. Press the minus sign (−) key.
To display a 3278 minus sign, press the minus sign key.

TN3270—Page Down and Page Up
If the 3270 application has a display that does not allow all the input data fields to
be viewed, use the 5250 Page Down and Page Up keys to enter data when the
maximum number of input fields on the display is exceeded.
You can also assign PF and PA functions to the page keys by specifying their use
on the STRTCPTELN command.
The cursor always appears as an underline on both 5250 and 3270 displays.

TN3270—Screen Size
Telnet 3270 full-screen mode requirements:
v If the negotiated 3270 device type requires 1920 characters, the AS/400 Telnet
client code will run with any 5250 device type as the client terminal.
v If the negotiated 3270 device type requires 3564 characters, the AS/400 Telnet
client code requires either a 3180 Model 2, 3197 Model D1, D2, W1, W2, or
3477 Model FA, FC, FD, FE, FG, or FW 5250 device type as the client terminal.

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161

TN3270—Cursor Select Key
The existing Cursor Select key is disabled if you choose to emulate the Cursor
Select key. The Cursor Select key is emulated if you specify one of the following
parameters for the STRTCPTELN command:
Parameter
Page Up (Roll Down) key
Page Down (Roll Up) key
Cursor Select key

Value
*CSRSLT
*CSRSLT
*F-key (specify a function key *F1 to *F24)

TN3270—Messages
Several types of error messages may be displayed when you are using Telnet 3270
full-screen mode.
v Key entry errors appear as flashing 4-digit numbers on the lower left corner of
the display. Press the Help key or F1 (Help) to obtain more information about the
message. See the System Operation book if you cannot correct the error.
v System messages include Telnet messages and are issued from the AS/400
system.
v For information on messages sent from the remote system, see the remote
system documentation.

TN3270—Handling Null Characters
All null characters are removed when a data stream is sent from a 3270 display
station. Specify one of the following values for the handle nulls (NULLS) parameter
on the STRTCPTELN command:
*REMOVE
Removes beginning and embedded null characters
*BLANK
The default value; changes beginning and embedded null characters to blanks
Trailing null characters are always removed for both values. For example, assume
the data consists of the following (0 indicates a null):
0x0yz000

The data stream sent from a 5250 display station running Telnet 3270 full-screen
with the default *BLANK would contain the following:
xyz

The data stream sent from a 3270 display station or from a 5250 display station
running a Telnet 3270 full-screen session when the value *REMOVE is specified
would contain the following:
xyz

The value *REMOVE is valid for the following devices:
v Any locally attached display
v Displays attached to a remote 5394 controller
v Personal computer displays using the workstation function

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VTxxx Full-Screen Mode Considerations
VT220 and VT100 terminals are ASCII full-screen terminals manufactured by Digital
Equipment Corporation (DEC) and are the full-screen terminal types supported by
AS/400. A typical example of a Telnet client VTxxx mode environment is shown in
Figure 106.
AS/400 System

Display
Device

Physical
Device
Description

IBM or Other System
TELNET
Client
Support

TCP/IP

TELNET
VTxxx
Server
Support

RV3H026-0

Figure 106. Typical Telnet VTxxx Mode Environment (Telnet Client)

When the VT220 terminal type is negotiated, there are several operating modes
that are supported:
v VT200 mode, 7-bit controls is the default mode and uses the standard ANSI
functions. This mode provides the full range of VT220 capabilities in an 8-bit
communications environment with 7-bit controls. This mode supports the DEC**
multinational character set or national replacement character (NRC) sets,
depending on the character set mode selected.
v VT200 mode, 8-bit controls uses the standard ANSI functions and provides the
full range of VT220 capabilities in an 8-bit communications environment with 8-bit
controls. This mode supports the DEC multinational character set or national
replacement character (NRC) sets, depending on the character set mode
selected.
v VT100 mode uses standard ANSI functions. This mode restricts the use of the
keyboard to VT100 keys. All data is restricted to 7 bits, and only ASCII, national
replacement characters (NRC), or special graphics characters are generated.
v VT52 mode uses DEC private functions (not ANSI). This mode restricts the use
of the keyboard to VT52 keys.
If VT220 mode is negotiated, then an initial operating mode for Telnet client is
selected using the ASCII operating mode (ASCOPRMOD) parameter of the
STRTCPTELN or Telnet command.
Telnet VTxxx support allows AS/400 users to sign on to non-AS/400 systems as if
they were on a VTxxx terminal locally attached to the system and to access
full-screen VTxxx applications. VTxxx client support allows an AS/400 user to sign
on to any remote system in a TCP/IP network that supports the VTxxx terminal data
stream.

Operational Differences
As an AS/400 Telnet user, you should be aware of physical and operational
differences between VTxxx and 5250 terminals.
The 5250 is a block mode terminal. Data typed on a 5250 is accumulated in a
buffer and only sent to the AS/400 system when an AID (attention identifier) key is

Chapter 5. Telnet Client

163

pressed. An AID key on a 5250 keyboard is a key that initiates a function. The
following are the AID keys on a 5250 keyboard:
v Clear
v Command Function 1 through 24
v Enter/Rec Adv
v Help
v Print
v Record Backspace Function
v Roll Down (Page Up)
v Roll Up (Page Down)
VTxxx terminals operate in a character mode. Characters are sent immediately to
the host when a key is pressed.
Another difference is the way the data arrives on the display. Data is written to a
VTxxx terminal one character at a time, and you see the data arrive as streams of
characters. With the 5250, data is written in blocks, and all or part of the display
changes at once.

Keyboard Issues
You should avoid using the 5250 cursor movement keys. Instead, you should use
the function keys associated with the *CSRUP, *CSRDOWN, *CSRRIGHT, and
*CSRLEFT keywords. By default these are keys F13, F14, F15 and F16
respectively. If you use the 5250 cursor movement keys, the VTxxx application you
are using may not function as expected because the results of using these keys are
not transmitted to the remote system until an attention identifier (AID) key is
pressed.
For example, using Telnet to the RISC System/6000 and obtaining VT220
emulation, the SMIT command provides a menu driven interface to AIX. Here the
function keys associated with *CSRxx keywords perform as you would expect the
cursor movement keys to do. However, the 5250 cursor movement keys, while
physically moving the cursor down the screen and correctly selecting the SMIT
option, do not cause the selected option to be highlighted. The highlighting in
reverse video remains with the first option on the SMIT menu, regardless of the key
position.
Typing a control character on an AS/400 keyboard is different than typing a control
character on an actual VTxxx terminal. On a VTxxx terminal, the control key is
pressed and held down while the character associated with the control function is
pressed. For example, the VTxxx Control-C function is entered by pressing the
following key sequence:

CTRL

C
RV2H015-1

Figure 107. VTxxx Control-C Sequence

When using the AS/400 Telnet support, the equivalent is achieved by typing a
two-character control indicator followed by pressing the function key associated with
the *SENDWOCR (Send without Carriage Return) default function (the F11 key).

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For example, if the default keyboard map and the default STRTCPTELN command
parameters are in effect, the VTxxx Control-C function can be entered by typing &C
followed by pressing the F11 key. (It can also be entered simply by using the
default keyboard map, but in case you are using an application where is
remapped, this example is included, and illustrates the principle of the
*SENDWOCR key.
The character used to indicate a control character can be selected on the
CTLCHAR parameter of the STRTCPTELN command. The default is &. The &C
characters must be the last characters typed before pressing the *SENDWOCR
function key or the &C is not interpreted as a control character. A control character is
only sent when the *SENDWOCR function key is pressed. You can assign
frequently used VTxxx control characters to a function key. An example of the Ctrl-C
command can be described as follows. When using Telnet client to connect to an
RS/6000 system, VT220 emulation will typically be negotiated. The Ctrl-C sequence
is an important one in AIX to end long running commands, such as PING. It is,
therefore, important that you know how to do this before issuing any RS/6000
commands. By default the sequence is &C . Note that these keys have to be
entered quickly, and it may take several attempts before the RS/6000 task accepts
the input.
If you do not want the characters that are being typed to be displayed, the function
key associated with the *HIDE function should be pressed (F6 on the default
keyboard map). This function should be used when typing a password.
If you want the characters that have been typed to be sent to the remote system for
processing without pressing the Enter key, you should press the function key
associated with the *SENDWOCR function (F11 on the default keyboard map).
It is often useful to be able to recall previously entered commands. On the AS/400
F9 often provides this function. On AIX, this can be activated by typing the
command set -o vi and pressing Enter. After this, you can start retrieving commands
with the sequence EscK. To perform this sequence using the default keyboard map
while in VTxxx emulation, you should use the sequence k. The Esc
character starts the command retrieval. The k can then be used to retrieve further
commands. While operating in this mode, the commands H for right, L for left, X for
delete, I for insert, and R for replace apply. The sequence i switches this
facility off.

Screen Issues
The character in the position just before the cursor position will always be blank.
The actual character is saved internally and is displayed when the display is
refreshed with the cursor in a different position.
A VTxxx application that uses row 1, column 1 of the display does not work the
same when using AS/400 Telnet client support. Most 5250-type display stations do
not allow input to row 1, column 1. If the VTxxx application positions the cursor at
row 1, column 1, the AS/400 system puts the cursor at row 1, column 2,
automatically.
Due to architectural differences, certain VTxxx commands or sequences are not
supported and are ignored. An example is downstream loadable character sets.

Chapter 5. Telnet Client

165

VTxxx—Screen Size
Telnet VTxxx full-screen mode supports the following screen sizes:
v On 3180 display stations:
– 24 x 80 VTxxx screens should display as 24 x 80.
– 24 x 132 VTxxx screens should display as 24 x 132.
v On 5250 display stations:
– 24 x 80 VTxxx screens should display as 24 x 80.
– 24 x 132 screens require the function key assigned to *SHIFTDSP (F10 on
the default keyboard map) to move the information on the screen right or left.

VTxxx—Character Attributes
A VTxxx terminal supports the following attributes:
v Blink
v Bold
v Reverse video
v Underline
v Any combination of the above
The 5250 data stream supports the previous attributes so that all of the VTxxx
attributes can be represented on a 5250 display station. However, there are some
limitations.
v The 5250 data stream can only support three of the character attributes at the
same time. If all VTxxx attributes are selected at the same time by the remote
system, the underline, blink, and reverse video attributes are displayed. Also, the
combination of underline, bold, and reverse image cannot be displayed on a
5250 display station. When a VTxxx application selects this combination,
underline and reverse image are displayed.
v The attribute byte takes up a space on the 5250 display stations that do not
support extended attributes. Attributes do not take up space on a VTxxx terminal.
This means that you do not see all of the data shown on the 5250 display if
character attributes are selected. When VTxxx data is received that is to be
displayed with character attributes, the position before the data is overlaid with
the 5250 attribute byte. The character that was displayed there is lost. If a
character is to be displayed in row 1, column 1 with the attributes set, that
character is not displayed. You can choose not to have the character attributes
displayed by specifying DSPCHRATTR(*NO) on the STRTCPTELN command.
This allows you to see all of the data on the display without attributes.
Note: This restriction is not applicable for displays that support extended attributes
such as the 3477 display.

VT100—Keyboard Indicator
A VT100 terminal has an L1 indicator that can be programmed for different
applications. This indicator is not emulated by the AS/400 Telnet support.

VTxxx—Start TCP/IP Telnet Command
The following optional parameters on the STRTCPTELN or Telnet command are
applicable during a VTxxx full-screen mode session:

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OS/400 TCP/IP Configuration and Reference V4R4

v
v
v
v
v

Control characters (CTLCHAR)
Incoming ASCII translation table (TBLVTIN)
Outgoing ASCII translation table (TBLVTOUT)
Special table out (TBLVTDRWO)
Special table in (TBLVTDRWI)

v
v
v
v
v
v
v

Options selected (VTOPT)
Display character attributes (DSPCHRATTR)
Page scroll feature (PAGESCROLL)
Answerback feature (ANSWERBACK)
Tab stops (TABSTOP)
Timeout wait for host (INZWAIT)
Coded character set identifier (CCSID)

v ASCII operating mode (ASCOPRMOD). This parameter applies to initializing a
VT220 session only and has no effect on negotiations. See “VTxxx Full-Screen
Mode Considerations” on page 163 for a description of the operating modes that
are supported.
v Port number of the remote host server application (PORT)
If unexpected characters appear, the remote server system may not be configured
correctly. Some server systems use a workstation-type system value to define the
capabilities of the client workstation. If you are connected to such a server system,
verify that the workstation-type value is set to an appropriate value for a VTxxx
full-screen mode workstation.
You can also use the set term command to change the full-screen mode of the
connection. For example, if you use Telnet to sign on to a RISC System/6000
(RS/6000) system, you should type:
set term=vt100

after the connection has been established. This should correctly map the
unexpected characters.

Changing the VTxxx Keyboard Map
The client session support for both the VT100 and VT220 modes provides a
primary and alternate keyboard mapping. This method of providing the keyboard
mapping is done to accommodate the additional keypad capabilities of the VT220
mode. All changes to these keyboard mappings can be saved for later sessions
using the F6 key from the Change VTxxx ... Keyboard Map display. The data is
saved in the user profile, and once saved will automatically apply the next time
Telnet VTxxx emulation is activated.
The keyboard option that you select from the Send Telnet Control Functions menu
determines which keyboard mapping you use. The following displays show the
VTxxx functions that correspond to the 5250 AID key.
v Option 6 (Change VT100 Primary Keyboard Map), shown in Figure 108 on
page 168 and Figure 109 on page 169.
v Option 7 (Change VT100 Alternate Keyboard Map), shown in Figure 110 on
page 169 and Figure 111 on page 170.
v Option 8 (Change VT220 Primary Keyboard Map), shown in Figure 112 on
page 170 and Figure 113 on page 171.
Chapter 5. Telnet Client

167

v Option 9 (Change VT220 Alternate Keyboard Map), shown in Figure 114 on
page 171 and Figure 115 on page 172.
The level of support negotiated between the AS/400 system and the server system
determines which options are displayed on the Send Telnet Control Functions
menu. If the VT100 full-screen mode support is negotiated initially, options 6 and 7
are displayed. If the VT220 full-screen mode support is negotiated initially, options 8
and 9 are displayed.
If you have previously installed TCP/IP at Version 2 Release 2, and upgrade to a
later version, and if you previously used VT100 emulation, then if the server system
is capable of negotiating the VT220 level of support, then the VT100 keyboard map
previously used on the AS/400 system is no longer used. Instead the VT220
keyboard map would be used.
Note: There are no differences in the default values of the VT100 primary and
alternate keyboard mappings.
The following figures show the default keyboard mappings. You can change any of
the values. If you press the Enter key, your changes are saved for the current
session only. If you press F6 (Save), your changes are permanently saved and are
in effect the next time you start a VTxxx Telnet session.
Change VT100 Primary Keyboard Map
Type changes, press Enter:
5250 key
VT100 function
Function Key 1 . . .
*PF1
Function Key 2 . . .
*PF2
Function Key 3 . . .
*PF3
Function Key 4 . . .
*PF4
Function Key 5 . . .
*ESC
Function Key 6 . . . *HIDE
Function Key 7 . . .
*TAB
Function Key 8 . . .
*CTLA
Function Key 9 . . .
*CTLB
Function Key 10 . .
*SHIFTDSP
Function Key 11 . .
*SENDWOCR
Function Key 12 . .
*CTLC
Function Key 13 . .
*CSRUP
Function Key 14 . .
*CSRDOWN
Function Key 15 . .
*CSRRIGHT
Function Key 16 . .
*CSRLEFT
F3=Exit

F6=Save

F12=Cancel

Figure 108. Change VT100 Primary Keyboard Map (Display 1)

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OS/400 TCP/IP Configuration and Reference V4R4

More...

Change VT100 Primary Keyboard Map
Type changes, press Enter:
5250 key
VT100 function
Function Key 17 . .
*CTLD
Function Key 18 . .
*CTLE
Function Key 19 . .
*CTLF
Function Key 20 . .
*CTLG
Function Key 21 . .
*CTLH
Function Key 22 . .
*CTLI
Function Key 23 . .
*CTLJ
Function Key 24 . .
*CTLK
Rollup key . . . . . *CTLL
Rolldown key . . . .
*CTLM

F3=Exit

F6=Save

F12=Cancel

Bottom

Figure 109. Change VT100 Primary Keyboard Map (Display 2)

Change VT100 Alternate Keyboard Map
Type changes, press Enter:
5250 key
VT100 function
Function Key 1 . . . *PF1
Function Key 2 . . .
*PF2
Function Key 3 . . . *PF3
Function Key 4 . . .
*PF4
Function Key 5 . . . *ESC
Function Key 6 . . . *HIDE
Function Key 7 . . . *TAB
Function Key 8 . . . *CTLA
Function Key 9 . . . *CTLB
Function Key 10 . .
*SHIFTDSP
Function Key 11 . .
*SENDWOCR
Function Key 12 . .
*CTLC
Function Key 13 . .
*CSRUP
Function Key 14 . .
*CSRDOWN
Function Key 15 . .
*CSRRIGHT
Function Key 16 . .
*CSRLEFT
F3=Exit

F6=Save

F12=Cancel

More...

Figure 110. Change VT100 Alternate Keyboard Map (Display 1)

Chapter 5. Telnet Client

169

Change VT100 Alternate Keyboard Map
Type changes, press Enter:
5250 key
VT100 function
Function Key 17 . .
*CTLD
Function Key 18 . .
*CTLE
Function Key 19 . .
*CTLF
Function Key 20 . .
*CTLG
Function Key 21 . .
*CTLH
Function Key 22 . .
*CTLI
Function Key 23 . .
*CTLJ
Function Key 24 . .
*CTLK
Rollup key . . . . .
*CTLL
Rolldown key . . . .
*CTLM

F3=Exit

F6=Save

F12=Cancel

Bottom

Figure 111. Change VT100 Alternate Keyboard Map (Display 2)

You can switch between the primary and alternate keyboard mappings during a
VTxxx session using the function key assigned to the *KEYPRI and *KEYALT
keywords. You can assign these keywords to any of the available 5250 function
keys. It is recommended that you assign *KEYPRI to the Page Up 5250 function
key and *KEYALT to the Page Down 5250 function key for both the primary and
alternate keyboard mappings.
Change VT220 Primary Keyboard Map
Type changes, press Enter:
5250 key
VT220 function
Function Key 1 . . .
*PF1
Function Key 2 . . .
*PF2
Function Key 3 . . .
*PF3
Function Key 4 . . .
*PF4
Function Key 5 . . .
*ESC
Function Key 6 . . . *HIDE
Function Key 7 . . .
*TAB
Function Key 8 . . .
*CTLA
Function Key 9 . . .
*CTLB
Function Key 10 . .
*SHIFTDSP
Function Key 11 . .
*SENDWOCR
Function Key 12 . .
*CTLC
Function Key 13 . .
*CSRUP
Function Key 14 . .
*CSRDOWN
Function Key 15 . .
*CSRRIGHT
Function Key 16 . .
*CSRLEFT
F3=Exit

F6=Save

F12=Cancel

Figure 112. Change VT220 Primary Keyboard Map (Display 1)

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OS/400 TCP/IP Configuration and Reference V4R4

More...

Change VT220 Primary Keyboard Map
Type changes, press Enter:
5250 key
VT220 function
Function Key 17 . .
*CTLD
Function Key 18 . .
*CTLE
Function Key 19 . .
*CTLF
Function Key 20 . .
*CTLG
Function Key 21 . .
*CTLH
Function Key 22 . .
*CTLI
Function Key 23 . .
*CTLJ
Function Key 24 . .
*CTLK
Page up (rolldown) .
*KEYPRI
Page down (rollup) .
*KEYALT

F3=Exit

F6=Save

Bottom

F12=Cancel

Figure 113. Change VT220 Primary Keyboard Map (Display 2)

Change VT220 Alternate Keyboard Map
Type changes, press Enter:
5250 key
VT220 function
Function Key 1 . . . *PF1
Function Key 2 . . .
*PF2
Function Key 3 . . . *PF3
Function Key 4 . . .
*PF4
Function Key 5 . . . *ESC
Function Key 6 . . . *HIDE
Function Key 7 . . . *TAB
Function Key 8 . . . *CTLA
Function Key 9 . . . *CTLB
Function Key 10 . .
*SHIFTDSP
Function Key 11 . .
*SENDWOCR
Function Key 12 . .
*CTLC
Function Key 13 . .
*CSRUP
Function Key 14 . .
*CSRDOWN
Function Key 15 . .
*CSRRIGHT
Function Key 16 . .
*CSRLEFT
F3=Exit

F6=Save

F12=Cancel

More...

Figure 114. Change VT220 Alternate Keyboard Map (Display 1)

Chapter 5. Telnet Client

171

Change VT220 Alternate Keyboard Map
Type changes, press Enter:
5250 key
VT220 function
Function Key 17 . .
*CTLD
Function Key 18 . .
*FINDKEY
Function Key 19 . .
*INSERTKEY
Function Key 20 . .
*REMOVEKEY
Function Key 21 . .
*SELECTKEY
Function Key 22 . .
*PREVSCN
Function Key 23 . .
*NEXTSCN
Function Key 24 . .
*CTLK
Rollup key . . . . .
*KEYPRI
Rolldown key . . . .
*KEYALT

F3=Exit

F6=Save

Bottom

F12=Cancel

Figure 115. Change VT220 Alternate Keyboard Map (Display 2)

There are several types of VTxxx information that you can enter.
v Character data. You can assign a character string to a function key. For
example, you are on the AS/400 system and are using Telnet to establish a
connection with an RS/6000 system. To assign the character string set
term=vt100 to the following function key:
Function Key 24

. .

*CTLK

from the AS/400 system you would type:
Function Key 24

. .

'set term=vt100'

This allows you to press a function key rather than always having to type in that
character string.
When you press the function key during a VTxxx session, the character string
assigned to the function key is sent to the remote system with the carriage
return, line feed characters added. If you type data before pressing the function
key, the character string is added to the data that you type. This allows you to
assign a frequently used command string to a function key. The character data
typed is mapped from EBCDIC to ASCII before being transmitted to the remote
system.
v Control key keywords. You can assign a VTxxx control keystroke to a function
key using a defined keyword. For example, if you wanted to assign a different
VTxxx control keystroke to the following function key:
Function Key 24

. .

*CTLK

. .

*CTLZ

you would type:
Function Key 24

When you press the function key, the new control character assigned to the
function key is sent to the remote system. If you type data before pressing the
function key, the control character is added to the typed data and sent to the
remote system.
v Hexadecimal data. You can assign a hexadecimal string to a function key. When
you press the function key, the hexadecimal data is sent to the remote system.

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OS/400 TCP/IP Configuration and Reference V4R4

The carriage return, line feed characters are not added to hexadecimal data. If
you type data before pressing the function key, the hexadecimal data is added to
the typed data and sent to the remote system. This allows you to type a
character that is not on the 5250 keyboard (for example, square brackets).
Hexadecimal data is entered by typing X followed by a quoted string of
hexadecimal characters, for example, X'1A1A'. The hexadecimal data is not
mapped before being transmitted to the remote system.
v Local AS/400 control functions. You can assign a keyword to be handled
locally within the AS/400 Telnet client session. These assignments or mappings
may not result in ASCII data stream traffic being sent to the remote Telnet server
session. These local control functions are *HIDE, *SHIFTDSP, *KEYPRI, and
*KEYALT. The *SENDWOCR function is a local function, but ASCII data streams
are sent to the remote Telnet server session.
Figure 116 shows the VT100 keyboard. Figure 117 on page 174 shows the VT220
keyboard. Table 10 on page 174 shows the valid control codes that are sent. The
CTRL key is used in conjunction with other keys on the keyboard to generate
control codes.

ONLINE
SET/
CLEAR
TABS

SETUP
ESC

!
1

TAB
CTRL

CAPS
LOCK
SHIFT

CLEAR LINE/
ALL TABS LOCAL

@
2

#
3

&
7

{
[

:
;

L
<

+
=

O
K

_
-

)
0

I
J

H
B

(
9

*
U

BELL
G
V

TOGGLE TRANSMIT RECEIVE 80/132
I/O
SPEED SPEED COLUMNS RESET

^
6

D
X

%
5
R

E
S

SETUP
A/B

$
4

KBD
LOCKED

LOCAL

PF2

PF3

PF4
-

‘
}
]

"
’
?
/

PF1

RETURN
SHIFT

|
\

LINE
FEED

’

RV2H014-2

Figure 116. VT100 Keyboard

Chapter 5. Telnet Client

173

Function Keys

Hold
Screen

Print
Screen

Data/
Talk

Set-up

Break

F11
(ESC)

F10

F12
(BS)

F13
(LF)

F14

Hold Screen

Lock Compose

Help

‘

2
Q

Tab

Ctrl

#
3

>
<

Shift

Lock

S
Z

%
5

R
D

(

)

T
F

Y
G

H
B

J
N

:
;

L
’
’

.
.

"
’
?
/

F17

F18

F19

F20

PF4

Find

Insert
Here

Remove

PF!

PF2

PF3

Select

Prev
Screen

Next
Screen

’

Enter

Return

}

{

Wait

\
Shift

Compose
Character

Editing
Keypad
Auxiliary
Keypad

Main Keypad

RV2N452

Figure 117. VT220 Keyboard
Table 10. VT100 and VT220 Control Character Keywords
Control Character
Description

Key Pressed with CTRL
Key Down

Keyword

Hex Character
Transmitted

Null

Spacebar

*NUL

X'00'

Start of heading

*SOH,*CTLA

X'01'

Start of text

*STX,*CTLB

X'02'

End of text

*ETX,*CTLC

X'03'

End of transmission

*EOT,*CTLD

X'04'

Enquire

*ENQ,*CTLE

X'05'

Acknowledge

*ACK,*CTLF

X'06'

Bell

*BEL,*CTLG

X'07'

Back Space

*BS,*CTLH

X'08'

Horizontal tabulation

*HT,*CTLI

X'09'

Line feed

*LF,*CTLJ

X'0A'

Vertical tab

*VT,*CTLK

X'0B'

Form feed

*FF,*CTLL

X'0C'

Carriage return

*CR,*CTLM

X'0D'

Shift out

*SO,*CTLN

X'0E'

Shift in

*SI,*CTLO

X'0F'

Data link escape

*DLE,*CTLP

X'10'

Device control 1

*DC1,*CTLQ

X'11'

Device control 2

*DC2,*CTLR

X'12'

Device control 3

*DC3,*CTLS

X'13'

Device control 4

*DC4,*CTLT

X'14'

Negative acknowledgement

*NAK,*CTLU

X'15'

174

OS/400 TCP/IP Configuration and Reference V4R4

Table 10. VT100 and VT220 Control Character Keywords (continued)
Control Character
Description

Key Pressed with CTRL
Key Down

Keyword

Hex Character
Transmitted

Synchronous idle

*SYN,*CTLV

X'16'

End of transmission block

*ETB,*CTLW

X'17'

Cancel previous word or
character

*CAN,*CTLX

X'18'

End of medium

*EM,*CTLY

X'19'

Substitute

*SUB,*CTLZ

X'1A'

Escape

[

*ESC

X'1B'

File separator

*FS

X'1C'

Group separator

]

*GS

X'1D'

Record separator

∼

*RS

X'1E'

Unit separator

*US

X'1F'

*DEL

X'7F'

Delete

Table 11 shows the keys on the auxiliary keypad that normally transmit the codes
for the numerals, decimal point, minus sign, and comma.
Table 11. Numeric Keypads
Keyword
*NUM0

Hex Character Transmitted

Numeric keypad 0 key (VT52 mode)

Numeric keypad 0 key (VT100 or VT220 7-bit mode)

X'30' or X'1B3F70'

X'30' or X'1B4F70'
2

Numeric keypad 0 key (VT220 8-bit mode)

X'30' or X'8F70'
*NUM1

Numeric keypad 1 key (VT52 mode)

Numeric keypad 1 key (VT100 or VT220 7-bit mode)

X'31' or X'1B3F71'
X'31' or X'1B4F71'
2

Numeric keypad 1 key (VT220 8-bit mode)

X'31' or X'8F71'
*NUM2

Numeric keypad 2 key (VT52 mode)

Numeric keypad 2 key (VT100 or VT220 7-bit mode)

X'32' or X'1B3F72'
X'32' or X'1B4F72'
2

Numeric keypad 2 key (VT220 8-bit mode)

X'32' or X'8F72'
*NUM3

Numeric keypad 3 key (VT52 mode)

Numeric keypad 3 key (VT100 or VT220 7-bit mode)

X'33' or X'1B3F73'
X'33' or X'1B4F73'
2

Numeric keypad 3 key (VT220 8-bit mode)

X'33' or X'8F73'
*NUM4

Numeric keypad 4 key (VT52 mode)

Numeric keypad 4 key (VT100 or VT220 7-bit mode)

X'34' or X'1B3F74'
X'34' or X'1B4F74'
2

Numeric keypad 4 key (VT220 8-bit mode)

X'34' or X'8F74'
*NUM5

Numeric keypad 5 key (VT52 mode)

Numeric keypad 5 key (VT100 or VT220 7-bit mode)

X'35' or X'1B3F75'
X'35' or X'1B4F75'
2

Numeric keypad 5 key (VT220 8-bit mode)

X'35' or X'8F75'
*NUM6

Numeric keypad 6 key (VT52 mode)

Numeric keypad 6 key (VT100 or VT220 7-bit mode)

X'36' or X'1B3F76'
X'36' or X'1B4F76'
2

X'36' or X'8F76'

Control Character Description

Numeric keypad 6 key (VT220 8-bit mode)

Chapter 5. Telnet Client

175

Table 11. Numeric Keypads (continued)
Keyword
*NUM7

Hex Character Transmitted

Numeric keypad 7 key (VT52 mode)

Numeric keypad 7 key (VT100 or VT220 7-bit mode)

X'37' or X'1B3F77'

X'37' or X'1B4F77'
2

Numeric keypad 7 key (VT220 8-bit mode)

X'37' or X'8F77'
*NUM8

Numeric keypad 8 key (VT52 mode)

Numeric keypad 8 key (VT100 or VT220 7-bit mode)

X'38' or X'1B3F78'
X'38' or X'1B4F78'
2

Numeric keypad 8 key (VT220 8-bit mode)

X'38' or X'8F78'
*NUM9

Numeric keypad 9 key (VT52 mode)

Numeric keypad 9 key (VT100 or VT220 7-bit mode)

X'39' or X'1B3F79'
X'39' or X'1B4F79'
2

Numeric keypad 9 key (VT220 8-bit mode)

X'39' or X'8F79'
*NUMMINUS

Numeric keypad minus key (VT52 mode)

Numeric keypad minus key (VT100 or VT220 7-bit mode)

X'2D' or X'1B3F6D'
X'2D' or X'1B4F6D'
2

Numeric keypad minus key (VT220 8-bit mode)

X'2D'or X'8F6D'
*NUMCOMMA

Numeric keypad comma key (VT52 mode)

Numeric keypad comma key (VT100 or VT220 7-bit mode)

X'2C' or X'1B3F6C'
X'2C' or X'1B4F6C'
2

Numeric keypad comma key (VT220 8-bit mode)

X'2C' or X'8F6C'
*NUMPERIOD

Numeric keypad period key (VT52 mode)

Numeric keypad period key (VT100 or VT220 7-bit mode)

X'2E' or X'1B3F6E'
X'2E' or X'1B4F6E'
2

*PF1

X'2E' or X'8F6E'

Numeric keypad period key (VT220 8-bit mode)

X'1B50'

Numeric keypad PF1 key (VT52 mode)

X'1B4F50'

Numeric keypad PF1 key (VT100 or VT220 7-bit mode)

*PF2

X'8F50'

Numeric keypad PF1 key (VT220 8-bit mode)

X'1B51'

Numeric keypad PF2 key (VT52 mode)

X'1B4F51'

Numeric keypad PF2 key (VT100 or VT220 7-bit mode)

*PF3

X'8F51'

Numeric keypad PF2 key (VT220 8-bit mode)

X'1B52'

Numeric keypad PF3 key (VT52 mode)

X'1B4F52'

Numeric keypad PF3 key (VT100 or VT220 7-bit mode)

*PF4

Control Character Description

X'8F52'

Numeric keypad PF3 key (VT220 8-bit mode)

X'1B53'

Numeric keypad PF4 key (VT52 mode)

X'1B4F53'

Numeric keypad PF4 key (VT100 or VT220 7-bit mode)

X'8F53'

Numeric keypad PF4 key (VT220 8-bit mode)

Notes:
1. A single-character is transmitted when in keypad numeric mode; a 3-character sequence is sent when in keypad
application mode.
2.

This sequence is a shortened version of the 7-bit sequence. It is either presented when operating in 8-bit mode,
which can be called by the remote VT220 host or server, or it may be specified in the ASCOPRMOD parameter
of the STRTCPTELN CL command.

Table 12 on page 177 shows the keys that transmit the codes for the function keys
on the top row of the VT220 keyboard.

176

OS/400 TCP/IP Configuration and Reference V4R4

Table 12. Top Row Function Keys
Keyword

Hex Character Transmitted

Control Character Description

*F6

X'1B5B31377E'

Top row F6 function key (VT220 7-bit mode)

X'9B31377E'
*F7

X'1B5B31387E'
X'9B31387E'

*F8

X'1B5B31397E'
X'9B31397E'

*F9

X'1B5B32307E'
X'9B32307E'

*F10

X'1B5B32317E'
X'9B32317E'

*F11

*F16 or *DO

*F17

*F18

*F19

*F20

X'1B5B32367E'
X'9B32367E'

*F15 or *HELP

X'1B5B32357E'
X'9B32357E'

*F14

X'1B5B32347E'
X'9B32347E'

*F13

X'1B5B32337E'
X'9B32337E'

*F12

Top row F6 function key (VT220 8-bit mode)
Top row F7 function key (VT220 7-bit mode)
Top row F7 function key (VT220 8-bit mode)
Top row F8 function key (VT220 7-bit mode)
Top row F8 function key (VT220 8-bit mode)
Top row F9 function key (VT220 7-bit mode)
Top row F9 function key (VT220 8-bit mode)
Top row F10 function key (VT220 7-bit mode)
Top row F10 function key (VT220 8-bit mode)
Top row F11 function key (VT220 7-bit mode)
Top row F11 function key (VT220 8-bit mode)
Top row F12 function key (VT220 7-bit mode)
Top row F12 function key (VT220 8-bit mode)
Top row F13 function key (VT220 7-bit mode)
Top row F13 function key (VT220 8-bit mode)
Top row F14 function key (VT220 7-bit mode)
Top row F14 function key (VT220 8-bit mode)

X'1B5B32387E'

Top row F15 function key (also HELP key) (VT220 7-bit
mode)

X'9B32387E'1

Top row F15 function key (also HELP key) (VT220 8-bit
mode)

X'1B5B32397E'

Top row F16 function key (also Do key) (VT220 7-bit mode)

X'9B32397E'1

Top row F16 function key (also Do key) (VT220 8-bit mode)

X'1B5B33317E'

Top row F17 function key (VT220 7-bit mode)

X'9B33317E'1

Top row F17 function key (VT220 8-bit mode)

X'1B5B33327E'

Top row F18 function key (VT220 7-bit mode)

X'9B33327E'1

Top row F18 function key (VT220 8-bit mode)

X'1B5B33337E'

Top row F19 function key (VT220 7-bit mode)

X'9B33337E'1

Top row F19 function key (VT220 8-bit mode)

X'1B5B33347E'

Top row F20 function key (VT220 7-bit mode)

X'9B33347E'

Top row F20 function key (VT220 8-bit mode)

Notes:
1.

This sequence is a shortened version of the 7-bit sequence. It is only presented when operating in 8-bit mode,
which can be called by the remote VT220 host or server, or it may be specified in the ASCOPRMOD parameter
of the STRTCPTELN CL command.

Table 13 on page 178 shows the keys that transmit codes for the editing keypad
keys.

Chapter 5. Telnet Client

177

Table 13. Editing Keypad
Keyword

Hex Character Transmitted

Control Character Description

*CSRUP

X'1B41'

Cursor-up key (VT52 mode)

X'1B5B41'

Cursor-up key (VT100 or VT220 7-bit Cursor Key Mode
Reset)

X'9B41'

Cursor-up key (VT220 8-bit Cursor Key Mode Reset)

X'1B4F41'

Cursor-up key (VT100 or VT220 7-bit Cursor Key Mode Set)

X'8F41'

Cursor-up key (VT220 8-bit Cursor Key Mode Set)

X'1B42'

Cursor-down key (VT52 mode)

X'1B5B42'

Cursor-down key (VT100 or VT220 7-bit Cursor Key Mode
Reset)

X'9B42'

Cursor-down key (VT220 8-bit mode Cursor Key Mode
Reset)

X'1B4F42'

Cursor-down key (VT100 or VT220 7-bit Cursor Key Mode
Set)

X'8F42'

Cursor-down key (VT220 8-bit mode Cursor Key Mode Set)

X'1B43'

Cursor-right key (VT52 mode)

X'1B5B43'

Cursor-right key (VT100 or VT220 7-bit Cursor Key Mode
Reset)

X'9B43'

Cursor-right key (VT220 8-bit Cursor Key Mode Reset)

X'1B4F43'

Cursor-right key (VT100 or VT220 7-bit Cursor Key Mode
Set)

X'8F43'

Cursor-right Key (VT220 8-bit Cursor Key Mode Set)

X'1B44'

Cursor-left key (VT52 mode)

X'1B5B44'

Cursor-left key (VT100 or VT220 7-bit Cursor Key Mode
Reset)

X'9B44'

Cursor-left key (VT220 8-bit Cursor Key Mode Reset)

X'1B4F44'

Cursor-left key (VT100 or VT220 7-bit Cursor Key Mode Set)

X'8F44'

Cursor-left key (VT220 8-bit Cursor Key Mode Set)

*CSRDOWN

*CSRRIGHT

*CSRLEFT

*FINDKEY

X'1B5B317E'
X'9B317E'

*INSERTKEY

X'1B5B327E'
X'9B327E'

*REMOVEKEY

X'1B5B367E'
X'9B367E'

178

X'1B5B357E'
X'9B357E'

*NEXTSCN

X'1B5B347E'
X'9B347E'

*PREVSCN

X'1B5B337E'
X'9B337E'

*SELECTKEY

OS/400 TCP/IP Configuration and Reference V4R4

Editing keypad Find key (VT220 7-bit mode)
Editing keypad Find key (VT220 8-bit mode)
Editing keypad Insert Here key (VT220 7-bit mode)
Editing keypad Insert Here key (VT220 8-bit mode)
Editing keypad Remove key (VT220 7-bit mode)
Editing keypad Remove key (VT220 8-bit mode)
Editing keypad Select key (VT220 7-bit mode)
Editing keypad Select key (VT220 8-bit mode)
Editing keypad Prev Screen key (VT220 7-bit mode)
Editing keypad Prev Screen key (VT220 8-bit mode)
Editing keypad Next Screen key (VT220 7-bit mode)
Editing keypad Next Screen key (VT220 8-bit mode)

Table 13. Editing Keypad (continued)
Keyword

Hex Character Transmitted

Control Character Description

Notes:
1. This sequence is a shortened version of the 7-bit sequence. It is only presented when operating in 8-bit mode,
which can be called by the remote VT220 host or server, or it may be specified in the ASCOPRMOD parameter
of the STRTCPTELN CL command.

Table 14 shows the keywords that are handled locally within the AS/400 Telnet
client session.
Table 14. Local AS/400 Function Keys
Keyword
*SENDWOCR
*SHIFTDSP
*HIDE
*KEYPRI
*KEYALT

Hex Character Transmitted

Control Character Description

None

VT100 and VT220 control key

None

Shift display

None

Hide input

None

Call primary keyboard mapping of 5250 function keys

None

Call alternate keyboard mapping of 5250 function keys

Notes:
1. The data that has been typed is sent to the remote system without appending the carriage return and line feed
characters.
2. The *SHIFTDSP keyword is used when the remote system has selected 132-column mode and the 5250 terminal
only has 80 columns. When the function key that has the *SHIFTDSP function assigned to it is pressed, the
rightmost 80 columns or the leftmost 80 columns are shown depending on what is currently on the display.
3.

The *HIDE keyword is used when the user does not want typed characters shown on the display, for example,
when typing a password.

4. The *KEYPRI and *KEYALT keywords signal the TELNET client session to dynamically call the respective
full-screen ASCII keyboard map. The *KEYPRI mapping calls the primary keyboard map, and *KEYALT calls the
alternate keyboard map. By default, they are assigned to the Page Down (Roll Up) and the Page Up (Roll Down)
5250 function keys. When the requested keyboard map is already in effect, no action is taken.

VTxxx—National Language Support
There are alternative methods of selecting character mapping between the client
and server systems with VTxxx emulation. These are:
v Coded character set identifier (CCSID)
v Multinational mode
v National mode
If none of these modes is suitable, you may set up and specify your own
user-defined mapping tables.
Note: VTxxx support is limited to a subset of single-byte character set (SBCS)
languages. A list of the supported languages is found later in this section.
Any of these supported single-byte language translation tables can be
modified to map any single-byte language that is preferred, then identified in
the appropriate parameter for starting Client Telnet.
Mode selection is done with the CCSID parameter of the Start TCP/IP Telnet
(STRTCPTELN) command. The incoming ASCII/EBCDIC table (TBLVTIN) and
outgoing EBCDIC/ASCII table (TBLVTOUT) parameters of this command allow the

Chapter 5. Telnet Client

179

specification of user-defined mapping tables. If these are not required, the default
value of *CCSID allows for character mapping by using the mode specified in the
CCSID parameter.

VTxxx—Multinational Mode
The multinational mode supports the DEC multinational character set, which is an
8-bit character set that contains most characters used in the major European
languages. The ASCII character set is included in the DEC multinational character
set. The DEC multinational character set is used by default.

VTxxx—National Mode
The national mode supports the national replacement character set, which is a
group of 7-bit character sets. Only one national character set is available for use at
any one time. VT220 also supports the standard 7-bit ASCII character set as part of
the national mode. The VT220 terminal supports the following 7-bit ASCII national
language character sets:
v British
v Dutch
v Finnish
v French
v French/Canadian
v
v
v
v
v
v

German
Italian
Norwegian Danish
Spanish
Swedish
Swiss

v US English
To use a national mode, mapping tables are required to map incoming ASCII data
into EBCDIC and outgoing EBCDIC data into ASCII when operating in VTxxx
full-screen mode.
A national mode (NLS mapping table) may be selected with the CCSID parameter
on the Telnet command (see “VTxxx—Start TCP/IP Telnet Command” on page 166).
A numeric value representing a registered CCSID value in the range 1-65553 may
be entered to identify the appropriate mapping table. Details of registered CCSIDs
are found in the International Application Development book.
The NLS mapping tables are built dynamically to a remote system the first time
Telnet is used, and are based on DEC national replacement character sets.
Because the character sets are based on 7 bits, they can contain only the unique
characters from one country. Because the DEC multinational character set is based
on 8 bits, it has sufficient bits to allow the unique characters from a group of
countries to be included.

180

OS/400 TCP/IP Configuration and Reference V4R4

Identifying Table Objects
You can identify the table objects (*TBL) using the Work with Object command:
WRKOBJ OBJ(QUSRSYS/Q*) OBJTYPE(*TBL)

All of the system table objects are in QUSRSYS library.
The table objects are named Qxxxyyyzzz where xxx is the FROM code page, yyy is
the TO character set and zzz is the TO code page.
For the outgoing (EBCDIC-to-ASCII) table:
v The FROM code page ID is taken from the code page ID in QCHRID of message
description CPX8416 (use WRKMSGD CPX8416 to display), 037 in Figure 118
from a US English based system.
v The TO character set and code page are derived from the CCSID parameter
used with the Telnet command. See Table 15 for the IDs used.
For the incoming (ASCII-to-EBCDIC) table:
v The FROM code page ID is derived from the CCSID parameter used with the
Telnet command. See Table 15 for the IDs used.
v The TO character set and code page are taken from the character set ID and
code page ID in QCHRID of message description CPX8416 (use WRKMSGD
CPX8416 to display), 697 and 037 in Figure 118 from a US English based
system.

Message ID . . . . . . . . . :
Message file . . . . . . . . :
Library . . . . . . . . . :

System:

CPX8416
QCPFMSG
QSYS

Message . . . . :
QCHRID
697 37
QCURSYM
QDECFMT
QLEAPADJ
0 QCCSID
37
QCNTRYID
US QIGCCDEFNT *NONE

$ QDATFMT
QTIMSEP

SYSNAM01

MDY QDATSEP
/
: QLANGID
ENU

Figure 118. Example CPX8416 Message
Table 15. ASCII/EBCDIC Translation Table Naming
Character Set
CCSID
MULTINAT
BRITISH
1292
1293
289
1192
265
293
1297
1195
1296
1193

Actual ID
1290
1291
A07
A08
289
A8E
265
293
BAB
A8H
BAA
A8F

Table ID
A05
A06
1102
1103
1104
1020
1011
1012
1107
1023
1106
1021

Code Page
Actual ID
1100
1101
A5W
A5X
A5Y
A3M
A3D
A3E
A52
A3P
A51
A3N

Table ID
A5U
A5V

Chapter 5. Telnet Client

181

For example, on a British system with a QCHRID of 697 285 (character set 697
code page 285) in message CPX8416 that uses Telnet with CCSID(*BRITISH), the
tables would have the following names:
v Outgoing (EBCDIC-to-ASCII) Q285A06A5V
v Incoming (ASCII-to-EBCDIC) QA5V697285

User-Defined Mapping Tables (ASCII Mode)
Where the multinational or NLS mapping tables do not meet the requirements of a
user, user-defined character mapping tables can be created and used.
You also have the ability to specify user-defined mapping tables using the outgoing
ASCII-to-EBCDIC table (TBLVTOUT) and incoming ASCII-to-EBCDIC table
(TBLVTIN) parameters of the STRTCPTELN command. You can specify a
user-defined mapping table for either the outgoing mapping table or the incoming
mapping table and then use the system default value for the other.
For details on how to create user-defined mapping tables, see Appendix C. Mapping
Tables Associated with TCP/IP Function.

System Functions Available during a Telnet Client Session
This material is covered in the AS/400e Information Center under the TCP/IP
topic. For more information see “TCP/IP Topics in the Information Center” on
page xv.

|
|
|

Print
Press the 5250-mode Print key to start the printing function and produce a printed
copy of the display. Press the Reset key to return to the Telnet session. The Print
key is always processed on the client system, so the spooled file created by the
Print key is placed on the job output queue on the client system. Refer to the
System Operation book for more information about working with and printing
spooled files.

182

OS/400 TCP/IP Configuration and Reference V4R4

Chapter 6. Telnet Server
|
|
|
|

Important note: A thorough and in-depth explanation of Telnet is beyond the scope
and purpose of this document. The majority of material on the Telnet server is
covered in the AS/400e Information Center under the TCP/IP topic. For more
information see “TCP/IP Topics in the Information Center” on page xv.

|
|
|

The topics that remain in this chapter include conceptual and reference information
on the Telnet server 3270 and VTxxx full-screen modes, and ASCII line and Printer
pass-through modes. Also in this chapter, you will find the following topics:

|
|
|
|

v Telnet scenarios for establishing cascaded sessions
v workstation type negotiations and mappings
v system API enhancement, including a discussion on dynamic application printing
with TCP/IP

Setting Up the Telnet Server
|
|
|

This material is covered in the AS/400e Information Center under the TCP/IP
topic. For more information see “TCP/IP Topics in the Information Center” on
page xv.

Determining Which Emulation Is Negotiated
To determine which type of emulation an autoselected Telnet client session
negotiates, the type of virtual device that is created should be examined by the
WRKDEVD QPADEV* command. For both VT220 and VT100, the virtual device
type that is created is V100. For virtual printer sessions, the device type that is
created is 3812 for single byte and 5553 for double byte.

5250 Full-Screen Mode
|
|
|

This material is covered in the AS/400e Information Center under the TCP/IP
topic. For more information see “TCP/IP Topics in the Information Center” on
page xv.

Examples of 5250 Server to 5250 Full-Screen Telnet Client
This topic describes some practical experiences of a 5250 full-screen Telnet server
with different 5250 clients.
OS/2
Apple Macintosh

OS/2 5250 Full-Screen Telnet Client
IBM TCP/IP Version 2.0 for OS/2 provides a 5250 full-screen Telnet client (TN5250).
TN5250 can be started either by clicking on the TN5250 icon or from an OS/2
command line. For example:
[C:\]tn5250 sysnam123

The session is ended by selecting Exit from the menu bar.

183

Keyboard Mapping: The default keyboard map can be changed by creating a file
named TN5250.KEY by using a text editor. For example, the following would map
the PS/2 Enter key (Enter key on numeric keypad) to the AS/400 Enter key
function:
enter enter

TN5250.KEY is searched for (and used if found) when TN5250 is called. OS/2 looks
for this file first in the current directory and then in the ETC directory. There is a list
of valid PS/2 keys and AS/400 functions plus a listing of the default keyboard map
in the IBM TCP/IP Version 2.0 for OS/2 User’s Guide.

Character Mapping: The PS/2 is an ASCII-based device. 5250 Telnet data
streams are in EBCDIC format. The PS/2 must, therefore, translate all incoming
data from EBCDIC to ASCII and all outgoing data from ASCII to EBCDIC. A default
mapping table is provided to do this. User-defined mapping tables can also be
created. A sample table (5250XLT.SAM) is provided in the ETC directory. The table
includes both ASCII-to-EBCDIC and EBCDIC-to-ASCII translation. A user-defined
mapping table is selected using the -tx option when starting a session, for example:
[C:\]tn5250 sysnam123 -tx 5250xlt.sam

Apple Macintosh 5250 Full-Screen Telnet Client
Apple SNAvps 5250 provides 5250 connectivity for Apple Macintosh computers.
Version 1.2 adds support for AppleTalk and TCP/IP. The TCP/IP support is used in
conjunction with TCP/IP Connection for Macintosh (M8113Z). This support provides
a TN5250 client that allows Apple Macintosh computers to connect directly (the
gateway support is SNA/APPC only) to an AS/400. Token-ring and Ethernet are
supported. LocalTalk/Ethernet gateways are available from third parties.
Once installed, the Macintosh TCP/IP support is configured using three displays in
two steps:
1. The first two displays are selected with the MacTCP control panel icon. Having
selected the type of network adapter to be used (token-ring or Ethernet) from
the first display, click on more for the second display. The following is configured
with the second display:
v
v
v
v

The gateway internet address
Your domain name
The name server internet address
Your internet address

The internet address of the gateway in our network example was 9.4.73.193.
This was entered in the Gateway Address field under Routing Information. Our
domain name of RCHLAND.IBM.COM was entered in the Domain field under
Domain Name Server Information. The name server internet address
(9.4.191.76 in our network example) was entered in the IP Address field, also
under Domain Name Server Information.
The IP Address section is used to enter your own internet address. Enter your
network class (A in our network example). The slider will now move to show the
bits allocated to the network ID (Net), 8-bits in our class A network example
(see Figure 119 on page 185). The slider bar must now be moved to correctly
divide the remaining section into Subnetwork ID (Subnet) and Host ID (Node).
The subnet mask in our network example was 255.255.255.192. As you move
the slider bar, the subnet mask ID is dynamically updated. You should now
move the bar until the subnet mask ID matches yours. At this point, the number

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OS/400 TCP/IP Configuration and Reference V4R4

of bits in the subnet and in the node in your network are shown. In the example
here, this equates to 18-bits allocated to the Subnet and 6-bits allocated to the
Node. For information on subaddressing, see “Subnetworks and Subnet Masks”
on page 6
Now enter your local internet address by entering information in the network ID
(Net), Subnetwork ID (Subnet), and Host ID (Node) fields. The information is
entered in these fields in decimal format. In our example the local IP address
in the more normal dotted decimal format was 9.4.73.214. This information was
entered as follows: 9 in the Net field, 5399 in the Subnet field and 22 in the
Node field. The example below shows how these numbers are derived from the
dotted decimal IP address once the internet address has been divided into Net,
Subnet and Node:
9

0 0 0 0 1 0 0 1

5
0 0 0 0 0 1 0 1

69
0 1 0 0 0 1 0 1

214
1 1 0 1 0 1 1 0

Net (class A)

Figure 119. Class A Network Example

Note:
The arithmetic involved in converting a dotted decimal address to the
required decimals for the subnet and node can be tedious. If you are
unsure of the value to put here, enter what you think it should be and
click on OK. An IP address will be displayed (corresponding to the
numbers you have entered) in the more normal dotted decimal format on
the previous panel. By now correcting the IP Address on this panel, and
selecting more again (do not press the Enter key after correcting the IP
address), you will see that the Macintosh has calculated the correct
Subnet and Node values on the next panel.
Once you are satisfied with this, click on OK and you are returned to the first
panel where your IP address is shown in dotted decimal format.
Having completed the above, close the MacTCP control panel and start the
Macintosh again.
2. The Macintosh host table information is configured with the third panel. Select
the SNAvps TCP/5250 option from the Apple Menu control panels option. Add
host names and addresses as required. Click on ADD to add a name entered to
the table.
To
1.
2.
3.
4.
5.

start a TN5250 session:
Select TCP/IP with SNAvps 5250 from the SNAvps folder.
Select Session from the menu bar
Select Connection from the menu bar
Select a Connection Type of 5250 Access/TCP.
Select the required host name from the list of configured Hosts.
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185

6. Click on tn5250 on the right side of the screen.
7. Click on Connect.
8. You should then be presented with an AS/400 sign-on display.
When the AS/400 sign-on display appears, it is inside a Macintosh Window. Along
the top of the window is a menu bar, where you see various options. Most of these
need not concern us. However, you should take note of the following:
Note: To end the session, select Session and then Disconnect from the menu bar.

Keyboard Mapping: A function key can be selected either with the mouse or with
the keyboard. To select a function key with the mouse, use the Keypad option from
the menu bar. A default keypad is provided (Standard Keypad). Others can be
created as required that might include Autokeys for example. To display the current
keyboard map, select Preferences and then Keyboard Map from the menu bar. The
keyboard map can also be changed from the panel presented using a ’drag and
drop’ process.
Character Mapping: The Apple Macintosh is an ASCII-based device. Because the
TN5250 data stream is EBCDIC-based, the Macintosh must do ASCII-to-EBCDIC
character translation. The translation table used is changed by selecting an
appropriate host language. To do this, select Session and then Host Language from
the menu bar. A list of the languages that are supported is presented from which a
language can be selected.
For more detailed information about configuring an Apple Macintosh to connect to
the AS/400 with both TCP/IP and SNA, see Using Apple Macintosh with the AS/400,
GG24-4071.

3270 Full-Screen Mode
3270 full-screen support allows Telnet client users to sign on and run AS/400 5250
full-screen applications even though 3270 full-screen support is negotiated. 3270
full-screen support is negotiated with any Telnet client application that supports
3270 full-screen applications rather than 5250 full-screen applications. An example
of a system that negotiates 3270 full-screen support is the System/390 family.
TN5250 delivers the data stream between the two systems as EBCDIC. Because
the 3270 data streams are translated into 5250 data streams, the workstation
devices operate as a remote 5251 display to the AS/400 system and application
programs.
Figure 120 on page 187 shows a network configuration using the AS/400 3270
Telnet server support.

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OS/400 TCP/IP Configuration and Reference V4R4

IBM System
Devices
3277
3278
3279

TCP/IP

AS/400 System
TELNET
Server
Support

Other System

Virtual
Device
Description

TCP/IP
Non-IBM
Terminal

TELNET
3270
Client
Support
RV2H000-2

Figure 120. Configuration Example of 3270 Telnet Server Support

Setting up for 3270 Full-Screen Mode
You can use the CFGTCPTELN command to set up your 3270 full-screen mode
session.
Configure TCP/IP TELNET
Select one of the following:

System:

SYSNAM01

1. Change TELNET attributes
6. Display 3270 keyboard map
7. Change 3270 keyboard map
8. Set 3270 keyboard map
Work with associated system values:
10. Autoconfigure virtual devices
11. Limit security officer device access
12. Inactive job time-out
13. Inactive job message queue
14. Limit device sessions
15. Action to take for failed sign-on attempts
16. Maximum sign-on attempts allowed
Selection or command
===>
F3=Exit
F4=Prompt

F9=Retrieve

More...

F12=Cancel

Figure 121. CFGTCPTELN in 3270 Full-Screen Session

Step 1—3270—Starting the Telnet Server Job
The server job for a TCP/IP application must be started in the QSYSWRK
subsystem. The Start TCP/IP Server (STRTCPSVR) command starts the servers
that are shipped with the TCP/IP Utilities licensed program.
Even though the Change Telnet Attributes (CHGTELNA) command has an
AUTOSTART parameter, that parameter is overridden or ignored by the
STRTCPSVR command.

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187

Step 2—3270—Setting the Number of Virtual Devices
The server system uses virtual devices to direct output to devices on your system.
AS/400 Telnet server support automatically selects (and creates, if necessary) these
devices for you. You may also choose to create your own virtual device under the
QVIRCDnnnn virtual controller. Note that virtual devices that you create under
QVIRCDnnnn will not be auto-selected. This would require a user exit program or
client subnegotiation to select this device.
The option is available for you to allow the Telnet server support on the AS/400
system to automatically configure virtual controllers and devices. The QAUTOVRT
system value specifies the maximum number of devices that are automatically
configured by the system. Use the Change System Value (CHGSYSVAL) command
to change the value of the QAUTOVRT system value. For example, entering the
following command string changes the number of virtual devices that can be
allocated on a system to 50:
CHGSYSVAL SYSVAL(QAUTOVRT) VALUE(50)

Note: QAUTOVRT has been modified for Version 4 Release 2 to support numeric
values of 0 through 32500, and a special value of *NOMAX.
To determine and set the maximum number of users you want signed on to the
AS/400 system at any time, do the following:
1. Set the QAUTOVRT value to 32500, the maximum value allowed, or use the
*NOMAX value.
2. Let your users use pass-through, Telnet, the virtual terminal application program
interface and Telnet Printer pass-through until you decide that the number of
virtual devices created is sufficient for normal system operation.
3. Change the QAUTOVRT value from 32500 to the number of virtual devices you
require for normal system operation.
If you have never allowed automatic configuration of virtual devices on your system,
the QAUTOVRT value is 0. A Telnet connection attempt with a dependence on
automatic creation of the virtual device then fails because the Telnet server does
not create more than the specified QAUTOVRT devices (zero). If you try to connect,
you receive a message (TCP2504) indicating that the Telnet client session has
ended and the connection is closed. In addition, the QTGTELNETS job in the
QSYSWRK subsystem on the AS/400 Telnet server sends a message (CPF8940)
indicating that a virtual device cannot be automatically selected.
If you change the QAUTOVRT value to 10, the next Telnet connection attempt
causes the Telnet server to create a virtual device. This virtual device is created
because the number of virtual devices on the controller (0) is less than the number
specified in the QAUTOVRT (10). Even if you change the specified number to 0
again, the next user attempting a Telnet connection succeeds. When a Telnet
connection attempt fails, the CPF87D7 message is sent to the system operator
message queue on the Telnet server system. The CPF87D7 message indicates that
the AS/400 server is not able to create a virtual device.
The Telnet server uses the following conventions for naming virtual controllers and
devices:
v Virtual controllers are named QPACTLnn.

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v Virtual device descriptions can be a name selected by the user. If a valid device
name is communicated to the Telnet server either via user exit or a Telnet client,
a device by that name will be created, if necessary, under virtual controller
QVIRCDnnnn.
The virtual controller descriptions (QPACTLnn) have the 5250 data stream
optimization switch (OPTDTASTR) set to *YES by default. There is no reason to
change this for use by 3270 Telnet.

Security Considerations for 3270 Full-Screen Mode: The number of sign-on
attempts allowed increases if virtual devices are automatically configured. The
number of sign-on attempts is equal to the number of system sign-on attempts
allowed multiplied by the number of virtual devices that can be created. The number
of system sign-on attempts allowed is defined by the QMAXSIGN system value.
The number of virtual devices that can be created is defined by the QAUTOVRT
system value.
In Version 4 Release 2, the following level of support has been added with regard
to security of virtual devices:
v With a user-supplied exit program, you can audit the number of sign-on attempts
v You have the ability to deny connections
v You have the ability to allow bypassing of the sign-on screen
For more information on Telnet exit points and how to use them, see “TELNET Exit
Points” on page 541 in Appendix E. TCP/IP Application Exit Points and Programs.

Telnet and SNA 5250 Pass-Through Considerations for 3270 Full-Screen
Mode: The AS/400 system supports 5250 pass-through. 5250 pass-through is
similar to Telnet but runs on an SNA (Systems Network Architecture) protocol
network rather than a TCP/IP network. 5250 pass-through uses virtual displays to
direct output to the physical devices just as Telnet does. In 5250 pass-through, the
AS/400 system automatically creates virtual devices in the same way that it does
for Telnet. Therefore, the QAUTOVRT system value controls the number of
automatically configured virtual devices for both 5250 pass-through and Telnet. For
more information about 5250 pass-through, see the Remote Work Station Support
book.

Step 3—3270—Setting the QLMTSECOFR Value
The OS/400 licensed program supports the limit security officer (QLMTSECOFR)
system value, which limits the devices the security officer can sign on to. If the
QLMTSECOFR value is greater than zero, the security officer must be authorized to
use the virtual device descriptions. However, when this value is 0, the system does
not limit the devices users with *ALLOBJ or *SERVICE special authority can sign on
to.
On AS/400 systems with a QSECURITY value of 30 or greater, a user with security
officer authority (*ALLOBJ) must be authorized to use devices before the system
allows the user to use those devices. For example, each display device that a
security officer wants to sign on to (local, remote, or virtual), must have had the
following authority specified with the Grant Object Authority (GRTOBJAUT)
command:
GRTOBJAUT

OBJ(display_name) OBJTYPE(*DEVD)
AUT(*CHANGE) USER(QSECOFR)

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189

This procedure is very important because Telnet automatically configures virtual
devices. If the QLMTSECOFR value is set to 0, all devices automatically configured
by Telnet can be used by the security officer. If you set the QLMTSECOFR value to
1, your security officer is not able to use the virtual devices created by Telnet unless
you grant object authority to the security officer for that virtual device. The automatic
configuration support can delete and re-create the virtual device. If this occurs,
authority must be granted to the security officer each time the virtual device is
created.

Step 4—3270—Working with Associated System Values

|
|
|
|
|
|
|

In addition to the QAUTOVRT and QLMTSECOFR, the following system values are
available for you to work with from the Configure TCP/IP Telnet (CFGTCPTELN)
menu:

|
|

v
v
v
v
v
v
v

v QDSCJOBITV: Time interval before disconnected jobs end

Figure 122 on page 192 shows the Configure TCP/IP Telnet (CFGTCPTELN) menu.

|
|

Setting the Telnet Timemark Timeout Value: You should also take into
consideration the TIMMRKTIMO parameter.

|
|
|

The Telnet timemark timeout (TIMMRKTIMO) parameter specifies the number of
seconds between TIMEMARK commands sent by the Telnet server. If Telnet is
unable to send the TIMEMARK command, it closes the connection.

QINACTITV: Inactive job time-out
QINACTMSGQ: Inactive job message queue
QLMTDEVSSN: Limit device sessions
QMAXSGNACN: Action to take for failed sign-on attempts
QMAXSIGN: Maximum sign-on attempts allowed
QRMTSIGN: Remote sign-on control
QDEVRCYACN: Device I/O error action

Step 5—3270—Creating Virtual Controllers and Devices
You can create virtual controllers and devices. If you create your own virtual
devices, by allowing the system to automatically select the device name, you must
be aware of the following:
v The virtual controller must be named QPACTLnn, where nn is a decimal number 01
or greater.
v The virtual device should be named QPADEVxxxx, where xxxx is an alphanumeric
character from 0001 to ZZZZ.
Note: Starting with Version 4 Release 2, the xxxx are no longer only numeric
characters, but also alphanumeric characters from 0001 to ZZZZ, allowing
a maximum of 1,679,615 unique names (devices).
If you want to use more than 32500 devices, which is the maximum value
for the QAUTOVRT system, you can set the QAUTOVRT system value to
*NOMAX to allow additional devices to be created.
v The Telnet server reuses available existing virtual devices that were auto-created
by selecting virtual devices of the same device type and model. When there are
no more device type and model matches, but there are still available virtual
devices, then the device type and model will be changed to match the client

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device and model negotiated. This is true only for auto-created (QPADEVnnn)
virtual devices. Typically, the auto-created virtual device will use the AS/400
system values for keyboard type, character set, and code page. Optionally, these
display device attributes may be more specifically defined through the exit
program or device specified client subnegotiation. Devices can also be selected
via the exit program interface as opposed to being negotiated.

Step 6—3270—Defining Workstations to Subsystems
When you use Telnet to sign-on to an AS/400 server, the sign-on screen may not
be displayed on your workstation. Before a user can sign on to the AS/400 server,
the workstation must be defined to the subsystem. If the workstation has not been
defined to the subsystem, you need to add a workstation entry to the subsystem
description under which you want your job to run on the AS/400 server. The
workstation in this case is the virtual display device automatically created by the
Telnet server (QPADEVxxxx). The workstation name or the workstation type must
be specified in the subsystem description on the AS/400 server. Use the Display
Subsystem Description (DSPSBSD) command to see the workstation entries
defined to a subsystem. (This only applies to display devices. Printer devices
typically run in the QSPL subsystem.) The following command can be used to add
all workstation types to a subsystem named QINTER:
ADDWSE SBSD(QINTER) WRKSTNTYPE(*ALL)

Note: The Add Work Station Entry (ADDWSE) command can be done when the
subsystem is active. However, the changes may or may not take effect
immediately. You may need to end and restart the subsystem.

Step 7—3270—Activating the QSYSWRK Subsystem
The QSYSWRK subsystem must be active. Use the Work with Subsystem
(WRKSBS) command to display the status of the subsystem.
The Telnet server must also be started. The interactive subsystem, QINTER, which
is used in previous examples in this chapter, needs to be started to run interactive
jobs for Telnet sessions. The spooling subsystem (QSPL) needs to be active to run
printer pass-through sessions.

Step 8—3270—Creating User Profiles for Telnet Users
At the server system, create one or more user profiles for Telnet users from other
systems. The default user profile is *SYS. The following example shows a sample
user profile:
CRTUSRPRF

USRPRF(CLERK1)
PASSWORD(unique-password)
JOBD(CLERKLIB/CLERKL1)
TEXT('User profile Clerks Group 1')

Step 9—3270—Checking the QKBDTYPE System Value
When the AS/400 Telnet server automatically creates virtual display devices, it uses
the QKBDTYPE system value to determine the keyboard type for the virtual device.
If the initial creation of the virtual device fails using the QKBDTYPE system value,
the Telnet server attempts to create the device again, using a keyboard type value
of USB. If the second attempt to create the virtual display device fails using the
value of USB, then a message (CPF87D7) indicating that the virtual device cannot
be automatically selected is sent to the system operator message queue.
Chapter 6. Telnet Server

191

Step 10—3270—Setting the Default Keyboard Mapping
A 3270 display station connected to an AS/400 system using Telnet appears to be a
5251 display station to an AS/400 system. The 3270 display station keyboard has a
5251-equivalent keyboard map associated with it which allows it to complete
5251-equivalent functions on the AS/400 system.
When a Telnet client system user first signs on in 3270 full-screen mode, the
AS/400 system automatically assigns the default keyboard map to the user’s 3277,
3278, or 3279 keyboard (unless a user-defined keyboard map has been set up to
be automatically included in the user’s profile sign-on procedure). This supplies the
mapping needed for the 3270 keyboards to do most of the same functions as their
5250-equivalent keyboards do.
Note: If you are satisfied with the default keyboard mapping supplied when you
sign on, you may skip the remainder of this topic and go to the next topic,
“Break Messages in 3270 Full-Screen Mode” on page 195.

Configure TCP/IP TELNET
Select one of the following:

System:

SYSNAM11

F4=Prompt

F9=Retrieve

More...

F12=Cancel

Figure 122. Configure TCP/IP TELNET Menu—TN3270

Displaying a Keyboard Map: Table 16 shows the default PF key assignments to
perform the various 5250 functions. You can use the Display Keyboard Map
(DSPKBDMAP) command to see the current keyboard mapping or use option 6
(Display 3270 keyboard map) on the Configure TCP/IP Telnet menu, while your
terminal is in 3270 emulation mode.
Table 16. Default Keyboard Mapping
5250 Key Function
Help
3270 Help
Clear
Print
Display Embedded Attributes
Test Request

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OS/400 TCP/IP Configuration and Reference V4R4

Default 3270 Keys to Select Function
PF1
PF2
PF3
PF4
PF5
PF6

Table 16. Default Keyboard Mapping (continued)
5250 Key Function
Default 3270 Keys to Select Function
Roll Down
PF7
Roll Up
PF8
Error Reset
PF10 (System/38), PF10 or Enter (System/36 and
AS/400 system)
Sys Req
PF11
Record Backspace
PF12
F1 through F12
Press PA1, then one of the following: PF1 through
PF121
F13 through F24
Press PA2, then one of the following: PF1 through
PF12, or PF13 through F24 (if present)
Field Exit
Erase EOF, then Field Tab
Attention
For 3277 use Test Request, then PA1. For
3278/3279 use Attn key
Notes:
1. For example, to start F3, press PA1, wait for the system to respond, and then press PF3.

Changing a Keyboard Map: If you want to make either minor changes to the
default keyboard map or to set a new keyboard map, use the Change Keyboard
Map (CHGKBDMAP) or the Set Keyboard Map (SETKBDMAP) command. These
commands are available from the Configure TCP/IP Telnet menu as option 7
(Change 3270 keyboard map) and option 8 (Set 3270 keyboard map), while your
terminal is in 3270 emulation mode. The key assignments you specify are in effect
until you use these commands again to specify new key assignments or until you
sign off.

Note
The difference between CHGKBDMAP and SETKBDMAP is that with
SETKBDMAP the system defaults are taken and then the changes in the
SETKBDMAP are applied. With CHGKBDMAP, the system defaults plus any
changes you have previously made during this session are taken and then the
changes in the CHGKBDMAP are applied.

The following example of a CL program sets the keyboard mapping for a 327x-type
terminal that is using Telnet to go to an AS/400 system. This program maps the
AS/400 function keys to their equivalent function keys on the 327x terminal. The
CPF8701 message is received if you attempt a CHGKBDMAP command from a
terminal not in 3270 emulation mode. By monitoring for it, the rest of the program is
not used in these circumstances.
PGM

MONMSG
MSGID(CPF8701 CPF0000)
CHGKBDMAP PF1(*F1) PF2(*F2) PF3(*F3) PF4(*F4) PF5(*F5)
PF6(*F6) PF7(*DOWN) PF8(*UP) PF9(*F9)
PF10(*F10) PF11(*F11) PF12(*F12)
PA1PF1(*HELP) PA1PF2(*HLP3270)
PA1PF3(*CLEAR) PA1PF4(*PRINT)
PA1PF5(*DSPATR) PA1PF6(*TEST) PA1PF7(*F7)
PA1PF8(*F8) PA1PF9(*ATTN) PA1PF10(*RESET)
PA1PF11(*SYSREQ) PA1PF12(*BCKSPC)
ENDPGM

By storing this CL source as part of the QCLSRC file in library TCPLIB as member
CHGKBD, you can create the CL program CHGKBD into the TCPLIB library by
using the following CL command:
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193

CRTCLPGM PGM(TCPLIB/CHGKBD) SRCFILE(TCPLIB/QCLSRC)
TEXT('Change the keyboard mapping for 327x terminals')

The CHGKBD program can then be called by anyone using Telnet to an AS/400
system. It can also be called automatically at sign-on time by specifying the
CHGKBD program for the Initial program parameter on the CHGUSRPRF command
or the CHGKBD program can be called by the profile’s initial program.

PA1 and PA2 Keys on a PC Keyboard: The PA1 and PA2 keys do not appear on
a PC keyboard. The function of these 3270 keys on a PC keyboard is provided by a
keyboard mapping in your 3270 emulator.
These keys are used by the default 3270 Telnet keyboard mapping, so it is
important that you know where these keys are on the keyboard before starting a
3270 Telnet session. This is especially important if you are planning to start a
session without changing the keyboard mapping. You should refer to your emulator
documentation for the keys or keystrokes required to provide these functions.
There are some 5250 key sequences for which there is no supported 3270 key
sequence and, therefore, it is not possible to set using the keyboard mapping
commands. These key sequences are:
v Field Plus
v Field Minus
v Erase all input fields
The 5250 Field Exit Key function is performed on a 3270 keyboard using the Erase
EOF key and then the tab key.
Note: When using Telnet 3270 full-screen mode from the 3270 terminal and before
the default mapping for the terminal is changed, the keys PF1 to PF12 might
be emulated by the key sequence PA1 PFx. Prior to creating a new
keyboard map, as in the previous example, instructions like Press PF3 or
Press PF4 should read: Press PA1 PF3 and Press PA1 PF4. In this case,
depending on the installation of the Telnet client for the host (VM Telnet client
for example), when pressing PA1 the user might get the instruction TELNET
command: at the bottom line of the display. If this instruction is displayed, then
type: PA1, press the Enter key, move the cursor to the command line and
press the desired PF key. In this case PF1 to PF12 might be emulated by:
1. Press PA1, get the Telnet instruction TELNET command:
2. Type PA1, press the Enter key.
3. Move the cursor to the command line.
4. Press the desired PF key.
For additional keyboard mapping information, see Appendix D. TELNET 3270
Keyboard Mappings.
Note: The Host Command Facility (HCF) is a feature available on System/370,
43xx, and 30xx host systems that enables a user on the host system to use
applications on an AS/400 system or other systems as if they were using
remotely attached 5250-type display stations. If you use HCF to connect to
an AS/400 system and then use Telnet to sign on to another AS/400 system
from that AS/400 system, you are in a 3270 full-screen mode session. The
keyboard is mapped twice, once for the initial HCF session and once for the
Telnet session. To use your PF keys the way you normally would, you must

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OS/400 TCP/IP Configuration and Reference V4R4

change the keyboard mapping on both AS/400 systems, making sure that
you use the same keyboard mapping on each AS/400 system.

Break Messages in 3270 Full-Screen Mode
When your workstation message queue is in break mode (you must specify
*BREAK on the CHGMSGQ command), messages appear on the 3270 device
exactly as they appear on the 5250 display. When your workstation is not in break
mode, the following message is displayed: A message has arrived on a message
queue. To continue, press the function key assigned to the help function or the
function key assigned the error reset function. Then use the Display Message
(DSPMSG) command or the function key assigned to the system request function
followed by option 4 (Display message) to view the waiting message. Set the
workstation message queue to break mode to see the messages as they arrive.

Input-Inhibited Light
When using an AS/400 system from a 5250-type terminal, pressing certain keys in
certain situations causes input to be inhibited and the input-inhibited light to be
displayed on the 5250 terminal. When using Telnet server 3270 full-screen mode,
the input-inhibited light is indicated by two asterisks shown in the lower right corner
of the display (see Figure 123).

F3=Exit
F4=Prompt
F5=Refresh
F24=More keys
FUNCTION KEY NOT ALLOWED.

F12=Cancel

Bottom
F13=How to use this display
**

Figure 123. Input-Inhibited Light

When the keyboard is inhibited, any keys mapped to the AS/400 function keys are
ignored. The keyboard must be reset by pressing the Enter key or by pressing the
key mapped to the AS/400 Reset key.

Defining Capabilities for 3270 Devices
Table 17 lists the capabilities of the 3270 devices supported by Telnet.
Make sure that your Telnet client 3270 is negotiating one of the supported 3270
terminal types. The supported terminal types are shown in Table 19 on page 230.
Table 17. 3270 Device Capabilities
Device Type
Device Capabilities
3277

This display station supports generic 3270 data streams. Extended
attributes, such as underlining, blinking, reverse image, or color are not
supported.

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195

Table 17. 3270 Device Capabilities (continued)
Device Type
Device Capabilities
3278

This display station supports extended attributes, such as blinking, reverse
image, and underlining if requested by the OS/400 DDS (data description
specifications) keywords.
Notes:
1. Extended attributes are not supported by some client implementations
of TELNET 3270 full-screen mode (TN3270).

3279

2. DBCS terminals that negotiate a 3278-2-E terminal type are
supported.
This display station supports color attributes and the extended data
stream attributes sent for a 3278 device. The color attributes are
determined (in the same manner as a 5292 Full Color Display) by
interpreting the DDS attributes as blinking, high intensity, or the DDS color
keywords.

VTxxx Full-Screen Mode
VTxxx server support allows Telnet client users to log on and run AS/400 5250
full-screen applications even though VTxxx full-screen support is negotiated. The
Telnet client application must be able to negotiate VTxxx terminal support. When
VTxxx full-screen mode is negotiated, the AS/400 Telnet server is responsible for
mapping 5250 functions to VTxxx keys and vice versa.
Although the AS/400 Telnet server supports VTxxx clients, this is not the preferred
mode to use because the AS/400 system is a block mode system, and the VTxxx
terminal is a character mode device. Most Telnet implementations support a
TN3270 or TN5250 client that should be used when connecting to an AS/400 Telnet
server.
In general, when a key on a VTxxx terminal is pressed, the hexadecimal code
associated with that key is immediately transmitted to the Telnet server. The Telnet
server must process that keystroke and then echo that character back to the VTxxx
terminal to be displayed. This results in a large amount of overhead associated with
each keystroke. In contrast, the 5250 and 3270 block mode devices buffer all
keystrokes at the client system until an Attention Identifier (AID) key is pressed.
When an AID key is pressed, the client sends the buffered input to the server for
processing. The block mode devices result in less overhead per keystroke and
generally provide better performance than a character-mode device, such as the
VTxxx terminal.
VTxxx delivers the data between the two systems as ASCII.

Setting up for VTxxx Full-Screen Mode
You can use the CFGTCPTELN command to set up your VTxxx full-screen mode
session.

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Configure TCP/IP TELNET
Select one of the following:
1.
2.
3.
4.
5.

System:

SYSNAM01

Change TELNET attributes
Set VT mapping tables
Display VT keyboard map
Change VT keyboard map
Set VT keyboard map

Work with associated system values:
10. Autoconfigure virtual devices
11. Limit security officer device access
12. Inactive job time-out
13. Inactive job message queue
14. Limit device sessions
15. Action to take for failed sign-on attempts
16. Maximum sign-on attempts allowed
More...
Selection or command
===>
F3=Exit

F4=Prompt

F9=Retrieve

F12=Cancel

Figure 124. CFGTCPTELN in VTxxx Full-Screen Session

Step 1—VTxxx—Starting the Telnet Server Job
The server job for a TCP/IP application must be started in the QSYSWRK
subsystem. The Start TCP/IP Server (STRTCPSVR) command starts the servers
that are shipped with the TCP/IP Utilities licensed program.
Even though the Change Telnet Attributes (CHGTELNA) command has an
AUTOSTART parameter, that parameter is overridden or ignored by the
STRTCPSVR command.

Step 2—VTxxx—Setting the Number of Virtual Devices
Virtual devices are used by the server system to direct output to devices on your
system. AS/400 Telnet server support automatically selects (and creates, if
necessary) these devices for you. You may also choose to create your own virtual
device under the QVIRCDnnnn virtual controller.
The option is available for you to allow the Telnet server support on the AS/400
system to automatically configure virtual controllers and devices. The QAUTOVRT
system value specifies the maximum number of devices that are automatically
configured by the system. Use the Change System Value (CHGSYSVAL) command
to change the value of the QAUTOVRT system value. For example, entering the
following command string changes the number of virtual devices that can be
allocated on a system to 50:
CHGSYSVAL SYSVAL(QAUTOVRT) VALUE(50)

197

1. Set the QAUTOVRT value to 32500, the maximum value allowed, or use the
*NOMAX value.
2. Let your users use pass-through, Telnet, and the virtual terminal application
program interface until you decide that the number of virtual devices created is
sufficient for normal system operation.
3. Change the QAUTOVRT value from 32500 to the number of virtual devices you
require for normal system operation.
If you have never allowed automatic configuration of virtual devices on your system,
the QAUTOVRT value is 0. A Telnet connection attempt with a dependence on
automatic creation of the virtual device then fails because the Telnet server does
not create more than the specified QAUTOVRT devices (zero). If you try to connect,
you receive a message (TCP2504) indicating that the Telnet client session has
ended and the connection is closed. In addition, the QTGTELNETS job in the
QSYSWRK subsystem on the AS/400 Telnet server sends a message (CPF8940)
indicating that a virtual device cannot be automatically selected.
If you change the QAUTOVRT value to 10, the next Telnet connection attempt
causes the Telnet server to create a virtual device. This virtual device is created
because the number of virtual devices on the controller (0) is less than the number
specified in the QAUTOVRT (10). Even if you change the specified number to 0
again, the next user attempting a Telnet connection succeeds. When a Telnet
connection attempt fails, the CPF87D7 message is sent to the system operator
message queue on the Telnet server system. The CPF87D7 message indicates that
the AS/400 server is not able to create a virtual device.

Security Considerations for VTxxx Full-Screen Mode: The number of sign-on
attempts allowed increases if virtual devices are automatically configured. The
number of sign-on attempts is equal to the number of system sign-on attempts
allowed multiplied by the number of virtual devices that can be created. The number
of system sign-on attempts allowed is defined by the QMAXSIGN system value.
The number of virtual devices that can be created is defined by the QAUTOVRT
system value.
In
to
v
v
v

Version 4 Release 2, the following level of support has been added with regard
security of virtual devices:
With a user-supplied exit program, you can audit the number of sign-on attempts
You have the ability to deny connections
You have the ability to allow bypassing of the sign-on screen

For more information on Telnet exit points and how to use them, see “TELNET Exit
Points” on page 541 in Appendix E. TCP/IP Application Exit Points and Programs.

Telnet and SNA 5250 Pass-Through Considerations for VTxxx Full-Screen
Mode: The AS/400 system supports 5250 pass-through. 5250 pass-through is
similar to Telnet but runs on an SNA (Systems Network Architecture) protocol
network rather than a TCP/IP network. 5250 pass-through uses virtual displays to
direct output to the physical devices just as Telnet does. In 5250 pass-through, the
AS/400 system automatically creates virtual devices in the same way that it does
for Telnet. Therefore, the QAUTOVRT system value controls the number of
automatically configured virtual devices for both 5250 pass-through and Telnet. For
more information about 5250 pass-through, see the Remote Work Station Support,
SC41-5402-00 book.

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Step 3—VTxxx—Setting the QLMTSECOFR Value
The OS/400 licensed program supports the limit security officer (QLMTSECOFR)
system value, which limits the devices the security officer can sign on to. If the
QLMTSECOFR value is greater than zero, the security officer must be authorized to
use the virtual device descriptions. However, when this value is 0, the system does
not limit the devices users with *ALLOBJ or *SERVICE special authority can sign on
to.
On AS/400 systems with a QSECURITY value of 30 or greater, a user with security
officer authority (*ALLOBJ) must be authorized to use devices before the system
allows the user to use those devices. For example, each display device that a
security officer wants to sign on to (local, remote, or virtual), must have had the
following authority specified with the Grant Object Authority (GRTOBJAUT)
command:
GRTOBJAUT

OBJ(display_name) OBJTYPE(*DEVD)
AUT(*CHANGE) USER(QSECOFR)

Step 4—VTxxx—Working with Associated System Values

|
|
|
|
|

In addition to the QAUTOVRT and QLMTSECOFR, the following system values are
available for you to work with from the Configure TCP/IP Telnet (CFGTCPTELN)
menu:
v QINACTITV: Inactive job time-out
v QINACTMSGQ: Inactive job message queue

|
|
|
|
|
|

v QLMTDEVSSN: Limit device sessions
v QMAXSGNACN: Action to take for failed sign-on attempts
v QMAXSIGN: Maximum sign-on attempts allowed

Figure 124 on page 197 shows the Configure TCP/IP Telnet (CFGTCPTELN) menu.

|
|

Setting the Telnet Timemark Timeout Value: You should also take into
consideration the TIMMRKTIMO parameter.

|
|
|

v QRMTSIGN: Remote sign-on control
v QDEVRCYACN: Device I/O error action
v QDSCJOBITV: Time interval before disconnected jobs end

Chapter 6. Telnet Server

199

Step 5—VTxxx—Creating Virtual Controllers and Devices
You can create virtual controllers and devices. If you create your own virtual
devices, by allowing the system to automatically select the device name, you must
be aware of the following:
v The virtual controller must be named QPACTLnn, where nn is a decimal number 01
or greater.
v The virtual device should be named QPADEVxxxx, where xxxx is an alphanumeric
character from 0001 to ZZZZ.
Note: Starting with Version 4 Release 2, the xxxx are no longer only numeric
characters, but also alphanumeric characters from 0001 to ZZZZ, allowing
a maximum of 1,679,615 unique names (devices).
If you want to use more than 32500 devices, which is the maximum value
for the QAUTOVRT system, you can set the QAUTOVRT system value to
*NOMAX to allow additional devices to be created.
v The Telnet server reuses available existing virtual devices that were auto-created
by selecting virtual devices of the same device type and model. When there are
no more device type and model matches, but there are still available virtual
devices, then the device type and model will be changed to match the client
device and model negotiated. This is true only for auto-created (QPADEVnnn)
virtual devices. Typically, the auto-created virtual device will use the AS/400
system values for keyboard type, character set, and code page. Optionally, these
display device attributes may be more specifically defined through the exit
program or device specified client subnegotiation. Devices can also be selected
via the exit program interface as opposed to being negotiated.
v The Device Type for a virtual device with VTxxx emulation is V100.

Step 6—VTxxx—Defining Workstations to Subsystems
When you use Telnet to sign-on to an AS/400 server, the sign-on screen may not
be displayed on your workstation. Before a user can sign on to the AS/400 server,
the workstation must be defined to the subsystem. If the workstation has not been
defined to the subsystem, you need to add a workstation entry to the subsystem
description under which you want your job to run on the AS/400 server. The
workstation in this case is the virtual display device automatically created by the
Telnet server (QPADEVxxxx). The workstation name or the workstation type must
be specified in the subsystem description on the AS/400 server. Use the Display
Subsystem Description (DSPSBSD) command to see the workstation entries
defined to a subsystem. (This only applies to display devices. Printer devices
typically run in the QSPL subsystem.)
Note: The Add Work Station Entry (ADDWSE) command can be done when the
subsystem is active. However, the changes may or may not take effect
immediately. You may need to end and restart the subsystem.

Step 7—VTxxx—Activating the QSYSWRK Subsystem
The QSYSWRK subsystem must be active. Use the Work with Subsystem
(WRKSBS) command to display the status of the subsystem.

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OS/400 TCP/IP Configuration and Reference V4R4

The Telnet server must also be started. The interactive subsystem, QINTER, which
is used in previous examples in this chapter, needs to be started to run interactive
jobs for Telnet sessions. The spooling subsystem (QSPL) needs to be active to run
printer pass-through sessions.

Step 8—VTxxx—Creating User Profiles for Telnet Users
At the server system, create one or more user profiles for Telnet users from other
systems. The default user profile is *SYS. The following example shows a sample
user profile:
CRTUSRPRF

USRPRF(CLERK1)
PASSWORD(unique-password)
JOBD(CLERKLIB/CLERKL1)
TEXT('User profile for Clerks Group 1')

Step 9—VTxxx—Checking the QKBDTYPE System Value
When the AS/400 Telnet server automatically creates virtual display devices, it uses
the QKBDTYPE system value to determine the keyboard type for the virtual device.
If the initial creation of the virtual device fails using the QKBDTYPE system value,
the Telnet server attempts to create the device again, using a keyboard type value
of USB. If the second attempt to create the keyboard type fails, then a message
(CPF87D7) is sent to the QTCPIP job log, indicating that the virtual device cannot
be automatically selected. This message is also sent to the system operator
message queue.

Step 10—VTxxx—Setting the Default Keyboard Mapping
When a Telnet session is negotiated in VTxxx full-screen mode, a default keyboard
map is used. To display the default keyboard map for VTxxx, use the Display VT
Keyboard Map command (DSPVTMAP) (see “Displaying a VTxxx Keyboard Map”
on page 205). To change the VTxxx keyboard map, use the Change VT Keyboard
Map (CHGVTMAP) command (see “Changing a VTxxx Keyboard Map” on
page 206) or the Set VT Keyboard Map (SETVTMAP) command (see “Setting a
VTxxx Keyboard Map” on page 206).
Because the VTxxx keyboard does not have the same keys as a 5250 keyboard, a
keyboard mapping must exist between the VTxxx keys and the AS/400 functions.
The AS/400 server assigns a default keyboard mapping when a VTxxx session is
first established. In some cases there can be more than one key or key sequence
that maps to a particular AS/400 function. In these cases, you can use any of the
defined keys to call the desired AS/400 function. Table 18 on page 202 shows the
5250 functions along with the default VTxxx key or key sequences that are mapped
to these functions.
Notes:
1. Each control character is a one-byte value that is generated from a VTxxx
keyboard by holding down the CTRL key while pressing one of the alphabetic
keys. Both shifted and unshifted control characters generate the same
hexadecimal values.
2. The escape sequences are multiple byte codes that are generated by pressing
the Esc key followed by the characters that make up the desired sequence.
3. The AS/400 server ignores the case of all alphabetic characters in an escape
sequence. You can type alphabetic characters in escape sequences in either
uppercase or lowercase.
Chapter 6. Telnet Server

201

4. The AS/400 F1-F12 functions are mapped to the Esc key followed by one of the
keys in the top row of a VTxxx keyboard. The F13-F24 functions are mapped to
the Esc key followed by a shifted key in the top row of a VTxxx keyboard.
5.

Some Telnet VTxxx client systems use Ctrl-S and Ctrl-Q for flow control
purposes. This is generally referred to as XON/XOFF flow control. If you are
using a client system that has XON/XOFF enabled, you should not use the
values *CTLS and *CTLQ in your keyboard mapping.

Table 18. Special Values for VTxxx Keys
Default 5250 Function

Special Value

VTxxx Keys

Hexadecimal Value1

Attention

*CTLA

X'01'

*ESCA

X'1B41'

Backspace

*BACKSPC

X'08'

Clear Screen

*ESCC

X'1B43'

Cursor Down

*CSRDOWN

X'1B5B42'

Cursor Left

*CSRLEFT

X'1B5B44'

Cursor Right

*CSRRIGHT

X'1B5B43'

Cursor Up

*CSRUP

X'1B5B41'

Delete

*DLT

X'7F'

*RMV

X'1B5B337E'2
X'9B337E'3

Duplicate

*ESCD

X'1B44'

Enter

*RETURN

X'0D'

Erase Input

*CTLE

X'05'

Error Reset

*CTLR

X'12'

*ESCR

X'1B52'

Field Advance

*TAB

X'09'

Field Backspace

*ESCTAB

X'1B09'

Field Exit

*CTLK

X'OB'

*CTLX

X'18'

*ESCX

X'1B58'

Field Minus

*ESCM

X'1B4D'

Help

*CTLQST

X'1F'

*ESCH

X'1B48'

Home

*CTLO

X'0F'

Insert

*ESCI

X'1B49'

*ESCDLT

X'1B7F'

*INS

X'1B5B327E'2
X'9B327E'3

New Line

202

*ESCLF

OS/400 TCP/IP Configuration and Reference V4R4

X'1B0A'

Table 18. Special Values for VTxxx Keys (continued)
Default 5250 Function

Special Value

VTxxx Keys

Hexadecimal Value1

Page Down (Roll Up)

*CTLD

X'04'

*CTLF

X'06'

*NXTSCR

X'1B5B367E'2
X'9B367E'3

Page Up (Roll Down)

*CTLB

X'02'

*CTLU

X'15'

*PRVSCR

X'1B5B357E'2
X'9B357E'3

*CTLP

X'10'

*ESCP

ESC

X'1B50'

*CTLL

X'0C'

*ESCL

X'1B4C'

*CTLC

X'03'

*ESCS

X'1B53'

Test Request

*CTLT

X'14'

Toggle Indicator Lights

*ESCT

X'1B54'

*ESC1

<1>

X'1B31'

Redraw Screen

System Request

*F1

X'1B5B31317E'2
X'9B31317E'3

*PF1

X'1B4F50'2
X'8F50'3

*ESC2
*F2

<2>

X'1B32'
X'1B5B31327E'2
X'9B31327E'3

*PF2

X'1B4F51'2
X'8F51'3

*ESC3
*F3

<3>

X'1B33'
X'1B5B31337E'2
X'9B31337E'3

*PF3

X'1B4F52'2
X'8F52'3

*ESC4
*F4

<4>

X'1B34'
X'1B5B31347E'2
X'9B31347E'3

*PF4

X'1B4F53'2
X'8F53'3

*ESC5
*F5

<5>

X'1B35'
X'1B5B31357E'2
X'9B31357E'3

Chapter 6. Telnet Server

203

Table 18. Special Values for VTxxx Keys (continued)
Default 5250 Function

Special Value

VTxxx Keys

Hexadecimal Value1

*ESC6

<6>

X'1B36'

*F6

X'1B5B31377E'2
X'9B31377E'3

*ESC7

<7>

X'1B37'

*F7

X'1B5B31387E'2
X'9B31387E'3

*ESC8

<8>

X'1B38'

*F8

X'1B5B31397E'2
X'9B31397E'3

*ESC9

<9>

X'1B39'

*F9

X'1B5B32307E'2
X'9B32307E'3

F10

*ESC0

<0>

X'1B30'

*F10

X'1B5B32317E'2
X'9B32317E'3

F11

*ESCMINUS

X'1B2D'

*F11

X'1B5B32337E'2
X'9B32337E'3

F12

*ESCEQ

X'1B3D'

*F12

X'1B5B32347E'2
X'9B32347E'3

F13

*ESCEXCL

X'1B21'

*F13

X'1B5B32357E'2
X'9B32357E'3

F14

*ESCAT

X'1B40'

*F14

X'1B5B32367E'2
X'9B32367E'3

F15

*ESCPOUND

X'1B23'

*F15

X'1B5B32387E'2
X'9B32387E'3

F16

*ESCDOLLAR

X'1B24'

*F16

X'1B5B32397E'2
X'9B32397E'3

F17

*ESCPCT

X'1B25'

*F17

X'1B5B33317E'2
X'9B33317E'3

F18

*ESCCFX

X'1B5E'1

*F18

X'1B5B33327E'2
X'9B33327E'3

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OS/400 TCP/IP Configuration and Reference V4R4

Table 18. Special Values for VTxxx Keys (continued)
Default 5250 Function

Special Value

VTxxx Keys

Hexadecimal Value1

F19

*ESCAMP

X'1B26'

*F19

X'1B5B33337E'2
X'9B33337E'3

F20

*ESCAST

X'1B2A'

*F20

X'1B5B33347E'2
X'9B33347E'3

F21

*ESCLPAR

X'1B50'

F22

*ESCRPAR

X'1B51'

F23

*ESCUS

X'1B5F'

F24

*ESCPLUS

X'1B2B'

See note 4

*FIND

X'1B5B317E'
X'9B317E'

See note 4

*SELECT