Authentication Authorization And Accounting Configuration Guide Cisco IOS XE Release 3S

User Manual:

Open the PDF directly: View PDF .
Page Count: 292

Download
Open PDF In Browser	View PDF

Authentication Authorization and Accounting Configuration Guide
Cisco IOS XE Release 3S

Americas Headquarters
Cisco Systems, Inc.
170 West Tasman Drive
San Jose, CA 95134-1706
USA
http://www.cisco.com
Tel: 408 526-4000
800 553-NETS (6387)
Fax: 408 527-0883

THE SPECIFICATIONS AND INFORMATION REGARDING THE PRODUCTS IN THIS MANUAL ARE SUBJECT TO CHANGE WITHOUT NOTICE. ALL STATEMENTS,
INFORMATION, AND RECOMMENDATIONS IN THIS MANUAL ARE BELIEVED TO BE ACCURATE BUT ARE PRESENTED WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED. USERS MUST TAKE FULL RESPONSIBILITY FOR THEIR APPLICATION OF ANY PRODUCTS.
THE SOFTWARE LICENSE AND LIMITED WARRANTY FOR THE ACCOMPANYING PRODUCT ARE SET FORTH IN THE INFORMATION PACKET THAT SHIPPED WITH
THE PRODUCT AND ARE INCORPORATED HEREIN BY THIS REFERENCE. IF YOU ARE UNABLE TO LOCATE THE SOFTWARE LICENSE OR LIMITED WARRANTY,
CONTACT YOUR CISCO REPRESENTATIVE FOR A COPY.
The Cisco implementation of TCP header compression is an adaptation of a program developed by the University of California, Berkeley (UCB) as part of UCB's public domain version
of the UNIX operating system. All rights reserved. Copyright © 1981, Regents of the University of California.
NOTWITHSTANDING ANY OTHER WARRANTY HEREIN, ALL DOCUMENT FILES AND SOFTWARE OF THESE SUPPLIERS ARE PROVIDED “AS IS" WITH ALL FAULTS.
CISCO AND THE ABOVE-NAMED SUPPLIERS DISCLAIM ALL WARRANTIES, EXPRESSED OR IMPLIED, INCLUDING, WITHOUT LIMITATION, THOSE OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OR ARISING FROM A COURSE OF DEALING, USAGE, OR TRADE PRACTICE.
IN NO EVENT SHALL CISCO OR ITS SUPPLIERS BE LIABLE FOR ANY INDIRECT, SPECIAL, CONSEQUENTIAL, OR INCIDENTAL DAMAGES, INCLUDING, WITHOUT
LIMITATION, LOST PROFITS OR LOSS OR DAMAGE TO DATA ARISING OUT OF THE USE OR INABILITY TO USE THIS MANUAL, EVEN IF CISCO OR ITS SUPPLIERS
HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network
topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional
and coincidental.
Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: http://

www.cisco.com/go/trademarks. Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership
relationship between Cisco and any other company. (1110R)
© 2015

CONTENTS

CHAPTER 1

Configuring Authentication 1
Finding Feature Information 1
Prerequisites for Configuring Authentication 1
Restrictions for Configuring Authentication 2
Information About Configuring Authentication 2
Named Method Lists for Authentication 2
Method Lists and Server Groups 2
Method List Examples 3
About RADIUS Change of Authorization 4
CoA Requests 5
RFC 5176 Compliance 5
CoA Request Response Code 6
Session Identification 7
CoA ACK Response Code 7
CoA NAK Response Code 7
CoA Request Commands 7
Session Reauthentication 8
Session Termination 8
CoA Request Disable Host Port 8
CoA Request Bounce Port 9
Domain Stripping 9
How to Configure AAA Authentication Methods 9
Configuring Login Authentication Using AAA 10
Login Authentication Using Enable Password 12
Login Authentication Using Kerberos 12
Login Authentication Using Line Password 12
Login Authentication Using Local Password 13
Login Authentication Using Group RADIUS 13

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
iii

Contents

Configuring RADIUS Attribute 8 in Access Requests 13
Login Authentication Using Group TACACS 13
Login Authentication Using group group-name 13
Configuring PPP Authentication Using AAA 14
PPP Authentication Using Kerberos 16
PPP Authentication Using Local Password 16
PPP Authentication Using Group RADIUS 16
Configuring RADIUS Attribute 44 in Access Requests 17
PPP Authentication Using Group TACACS 17
PPP Authentication Using group group-name 17
Configuring AAA Scalability for PPP Requests 17
Configuring ARAP Authentication Using AAA 18
ARAP Authentication Allowing Authorized Guest Logins 20
ARAP Authentication Allowing Guest Logins 20
ARAP Authentication Using Line Password 21
ARAP Authentication Using Local Password 21
ARAP Authentication Using Group RADIUS 21
ARAP Authentication Using Group TACACS 21
ARAP Authentication Using Group group-name 21
Configuring NASI Authentication Using AAA 22
NASI Authentication Using Enable Password 24
NASI Authentication Using Line Password 24
NASI Authentication Using Local Password 24
NASI Authentication Using Group RADIUS 24
NASI Authentication Using Group TACACS 25
NASI Authentication Using group group-name 25
Specifying the Amount of Time for Login Input 25
Enabling Password Protection at the Privileged Level 26
Changing the Text Displayed at the Password Prompt 27
Preventing an Access Request with a Blank Username from Being Sent to the RADIUS
Server 27
Configuring Message Banners for AAA Authentication 28
Configuring a Login Banner 28
Configuring a Failed-Login Banner 29
Configuring AAA Packet of Disconnect 30

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
iv

Contents

Enabling Double Authentication 31
How Double Authentication Works 31
Configuring Double Authentication 32
Accessing the User Profile After Double Authentication 33
Enabling Automated Double Authentication 34
Configuring Automated Double Authentication 35
Troubleshooting Automated Double Authentication 36
Configuring the Dynamic Authorization Service for RADIUS CoA 36
Configuring a Device to Ignore Bounce and Disable RADIUS CoA Requests 38
Configuring Domain Stripping at the Server Group Level 39
Non-AAA Authentication Methods 40
Configuring Line Password Protection 40
Establishing Username Authentication 42
Enabling CHAP or PAP Authentication 43
Enabling PPP Encapsulation 44
Enabling PAP or CHAP 44
Inbound and Outbound Authentication 45
Enabling Outbound PAP Authentication 45
Refusing PAP Authentication Requests 46
Creating a Common CHAP Password 46
Refusing CHAP Authentication Requests 46
Delaying CHAP Authentication Until Peer Authenticates 47
Using MS-CHAP 47
Defining PPP Authentication using MS-CHAP 48
Authentication Examples 49
RADIUS Authentication Examples 49
TACACS Authentication Examples 50
Kerberos Authentication Examples 51
AAA Scalability Example 51
Example: Configuring Login and Failed-Login Banners for AAA Authentication 53
AAA Packet of Disconnect Server Key Example 53
Double Authentication Examples 53
Configuration of the Local Host for AAA with Double Authentication Examples 54
Configuration of the AAA Server for First-Stage PPP Authentication and Authorization
Example 54

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
v

Contents

Configuration of the AAA Server for Second-Stage Per-User Authentication and
Authorization Examples 55
Complete Configuration with TACACS Example 55
Automated Double Authentication Example 58
Additional References 60
Feature Information for Configuring Authentication 62

CHAPTER 2

RADIUS Change of Authorization 67
Finding Feature Information 67
Information About RADIUS Change of Authorization 67
About RADIUS Change of Authorization 67
CoA Requests 68
RFC 5176 Compliance 68
CoA Request Response Code 69
Session Identification 70
CoA ACK Response Code 70
CoA NAK Response Code 70
CoA Request Commands 70
Session Reauthentication 71
Session Termination 71
CoA Request Disable Host Port 71
CoA Request Bounce Port 72
How to Configure RADIUS Change of Authorization 72
Configuring RADIUS Change of Authorization 72
Configuring a Device to Ignore Bounce and Disable RADIUS CoA Requests 74
Configuring the Dynamic Authorization Service for RADIUS CoA 75
Monitoring and Troubleshooting RADIUS Change of Authorization 76
Configuration Examples for RADIUS Change of Authorization 77
Example: Configuring RADIUS Change of Authorization 77
Example: Configuring a Device to Ignore Bounce and Disable a RADIUS Requests 77
Example: Configuring the Dynamic Authorization Service for RADIUS CoA 78
Additional References for RADIUS Change of Authorization 78
Feature Information for RADIUS Change of Authorization 79

CHAPTER 3

Message Banners for AAA Authentication 81

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
vi

Contents

Finding Feature Information 81
Information About Message Banners for AAA Authentication 81
Login and Failed-Login Banners for AAA Authentication 81
How to Configure Message Banners for AAA Authentication 82
Configuring a Login Banner for AAA Authentication 82
Configuring a Failed-Login Banner for AAA Authentication 83
Configuration Examples for Message Banners for AAA Authentication 84
Example: Configuring Login and Failed-Login Banners for AAA Authentication 84
Additional References for Message Banners for AAA Authentication 85
Feature Information for Message Banners for AAA Authentication 86

CHAPTER 4

AAA-Domain Stripping at Server Group Level 87
Finding Feature Information 87
Information About AAA-Domain Stripping at Server Group Level 87
How to Configure AAA-Domain Stripping at Server Level Group 88
Configuring Domain Stripping at the Server Group Level 88
Configuration Example for AAA-Domain Stripping at Server Group Level 89
Example: AAA-Domain Stripping at Server Group Level 89
Additional References 89
Feature Information for AAA-Domain Stripping at Server Group Level 91

CHAPTER 5

AAA Double Authentication Secured by Absolute Timeout 93
Finding Feature Information 93
Prerequisites for AAA Double Authentication Secured by Absolute Timeout 94
Restrictions for AAA Double Authentication Secured by Absolute Timeout 94
Information About AAA Double Authentication Secured by Absolute Timeout 94
AAA Double Authentication 94
How to Apply AAA Double Authentication Secured by Absolute Timeout 95
Applying AAA Double Authentication Secured by Absolute Timeout 95
Verifying AAA Double Authentication Secured by Absolute Timeout 95
Configuration Examples for AAA Double Authentication Secured by Absolute Timeout 98
Example: RADIUS User Profile 98
Example: TACACS User Profile 98
Additional References 100
Feature Information for AAA Double Authentication Secured by Absolute Timeout 101

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
vii

Contents

CHAPTER 6

Throttling of AAA RADIUS Records 103
Finding Feature Information 103
Information About Throttling of AAA RADIUS Records 103
Benefits of the Throttling of AAA RADIUS Records Feature 103
Throttling Access Requests and Accounting Records 104
How to Configure Throttling of AAA RADIUS Records 104
Throttling Accounting and Access Request Packets Globally 105
Throttling Accounting and Access Request Packets Per Server Group 106
Configuration Examples for Throttling of AAA RADIUS Records 107
Throttling Accounting and Access Request Packets Globally Example 107
Throttling Accounting and Access Request Packets Per Server Group Example 107
Additional References 108
Feature Information for Throttling of AAA RADIUS Records 109

CHAPTER 7

RADIUS Packet of Disconnect 111
Finding Feature Information 111
Prerequisites for RADIUS Packet of Disconnect 111
Restrictions for RADIUS Packet of Disconnect 111
Information About RADIUS Packet of Disconnect 112
When the POD is Needed 112
POD Parameters 112
How to Configure the RADIUS Packet of Disconnect 113
Configuring the RADIUS POD 113
Troubleshooting Tips 115
Verifying the RADIUS POD Configuration 115
Additional References 115
Feature Information for RADIUS Packet of Disconnect 117
Glossary 117

CHAPTER 8

AAA Authorization and Authentication Cache 119
Finding Feature Information 119
Prerequisites for Implementing Authorization and Authentication Profile Caching 120
Information About Implementing Authorization and Authentication Profile Caching 120

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
viii

Contents

Network Performance Optimization Using Authorization and Authentication Profile
Caching 120
Authorization and Authentication Profile Caching as a Failover Mechanism 120
Method Lists in Authorization and Authentication Profile Caching 121
Authorization and Authentication Profile Caching Guidelines 121
General Configuration Procedure for Implementing Authorization and Authentication Profile
Caching 121
How to Implement Authorization and Authentication Profile Caching 122
Creating Cache Profile Groups and Defining Caching Rules 122
Defining RADIUS and TACACS Server Groups That Use Cache Profile Group
Information 124
Updating Authorization and Authentication Method Lists to Specify How Cache Information
is Used 126
Configuration Examples for Implementing Authorization and Authentication Profile Caching 128
Implementing Authorization and Authentication Profile Caching for Network Optimization
Example 128
Implementing Authorization and Authentication Profile Caching as a Failover Mechanism
Example 129
Additional References for RADIUS Change of Authorization 131
Feature Information for Implementing Authorization and Authentication Profile Caching 132

CHAPTER 9

Configuring Authorization 135
Finding Feature Information 135
AAA Authorization Prerequisites 135
Information About Configuring Authorization 136
Named Method Lists for Authorization 136
AAA Authorization Methods 137
Authorization Methods 137
Method Lists and Server Groups 138
AAA Authorization Types 138
Authorization Types 139
Authorization Attribute-Value Pairs 139
How to Configure Authorization 139
Configuring AAA Authorization Using Named Method Lists 139
Disabling Authorization for Global Configuration Commands 141

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
ix

Contents

Configuring Authorization for Reverse Telnet 141
Authorization Configuration Examples 142
TACACS Authorization Examples 142
RADIUS Authorization Example 143
Reverse Telnet Authorization Examples 143
Additional References 145
Feature Information for Configuring Authorization 146

CHAPTER 10

Configuring Accounting 147
Finding Feature Information 147
Prerequisites for Configuring Accounting 147
Restrictions for Configuring Accounting 148
Information About Configuring Accounting 148
Named Method Lists for Accounting 148
Method Lists and Server Groups 149
AAA Accounting Methods 150
Accounting Record Types 150
Accounting Methods 150
AAA Accounting Types 151
Network Accounting 152
EXEC Accounting 154
Command Accounting 155
Connection Accounting 156
System Accounting 158
Resource Accounting 158
AAA Resource Failure Stop Accounting 158
AAA Resource Accounting for Start-Stop Records 160
AAA Accounting Enhancements 160
AAA Broadcast Accounting 160
AAA Session MIB 161
Accounting Attribute-Value Pairs 162
How to Configure AAA Accounting 162
Configuring AAA Accounting Using Named Method Lists 162
Suppressing Generation of Accounting Records for Null Username Sessions 163
Generating Interim Accounting Records 164

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
x

Contents

Configuring an Alternate Method to Enable Periodic Accounting Records 164
Generating Interim Service Accounting Records 165
Generating Accounting Records for a Failed Login or Session 166
Specifying Accounting NETWORK-Stop Records Before EXEC-Stop Records 167
Suppressing System Accounting Records over Switchover 167
Configuring AAA Resource Failure Stop Accounting 168
Configuring AAA Resource Accounting for Start-Stop Records 168
Configuring AAA Broadcast Accounting 169
Configuring per-DNIS AAA Broadcast Accounting 169
Configuring the AAA Session MIB 169
Establishing a Session with a Router if the AAA Server Is Unreachable 170
Monitoring Accounting 170
Troubleshooting Accounting 170
Configuration Examples for AAA Accounting 171
Configuring a Named Method List Example 171
Configuring AAA Resource Accounting Example 173
Configuring AAA Broadcast Accounting Example 173
Configuring per-DNIS AAA Broadcast Accounting Example 174
AAA Session MIB Example 174
Additional References 174
Feature Information for Configuring Accounting 176

CHAPTER 11

AAA-SERVER-MIB Set Operation 179
Finding Feature Information 179
Prerequisites for AAA-SERVER-MIB Set Operation 180
Restrictions for AAA-SERVER-MIB Set Operation 180
Information About AAA-SERVER-MIB Set Operation 180
CISCO-AAA-SERVER-MIB 180
CISCO-AAA-SERVER-MIB Set Operation 180
How to Configure AAA-SERVER-MIB Set Operation 180
Verifying RADIUS Server Configuration and Server Statistics 181
Configuration Examples for AAA-SERVER-MIB Set Operation 181
RADIUS Server Configuration and Server Statistics Example 181
Additional References 183
Feature Information for AAA-SERVER-MIB Set Operation 184

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
xi

Contents

CHAPTER 12

Per VRF AAA 187
Prerequisites for Per VRF AAA 187
Restrictions for Per VRF AAA 187
Information About Per VRF AAA 188
How Per VRF AAA Works 188
AAA Accounting Records 188
New Vendor-Specific Attributes 189
VRF Aware Framed-Routes 194
How to Configure Per VRF AAA 194
Configuring Per VRF AAA 194
Configuring AAA 194
Configuring Server Groups 195
Configuring Authentication Authorization and Accounting for Per VRF AAA 196
Configuring RADIUS-Specific Commands for Per VRF AAA 198
Configuring Interface-Specific Commands for Per VRF AAA 199
Configuring Per VRF AAA Using Local Customer Templates 200
Configuring AAA 200
Configuring Server Groups 200
Configuring Authentication Authorization and Accounting for Per VRF AAA 200
Configuring Authorization for Per VRF AAA with Local Customer Templates 201
Configuring Local Customer Templates 201
Configuring Per VRF AAA Using Remote Customer Templates 203
Configuring AAA 203
Configuring Server Groups 203
Configuring Authentication for Per VRF AAA with Remote Customer Profiles 203
Configuring Authorization for Per VRF AAA with Remote Customer Profiles 204
Configuring the RADIUS Profile on the SP RADIUS Server 205
Verifying VRF Routing Configurations 205
Troubleshooting Per VRF AAA Configurations 207
Configuration Examples for Per VRF AAA 207
Per VRF Configuration Examples 207
Per VRF AAA Example 207
Per VRF AAA Using a Locally Defined Customer Template Example 208
Per VRF AAA Using a Remote RADIUS Customer Template Example 208

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
xii

Contents

Customer Template Examples 209
Locally Configured Customer Template with RADIUS Attribute Screening and Broadcast
Accounting Example 209
Remotely Configured Customer Template with RADIUS Attribute Screening and Broadcast
Accounting Example 210
AAA Accounting Stop Record Examples 210
AAA Accounting Stop Record and Rejected Call Example 211
AAA Accounting Stop Record and Successful Call Example 213
Additional References 215
Feature Information for Per VRF AAA 216
Glossary 218

CHAPTER 13

AAA Support for IPv6 221
Finding Feature Information 221
Information About AAA Support for IPv6 221
AAA over IPv6 221
RADIUS over IPv6 222
Prerequisites for Using AAA Attributes for IPv6 222
RADIUS Per-User Attributes for Virtual Access in IPv6 Environments 222
How to Configure AAA Support for IPv6 226
Configuring DHCPv6 AAA Options 226
Configuration Examples for AAA Support for IPv6 227
Example: DHCPv6 AAA Options Configuration 227
Example: RADIUS Configuration 227
Additional References 227
Feature Information for RADIUS over IPv6 229

CHAPTER 14

TACACS+ over IPv6 231
Finding Feature Information 231
Information About TACACS+ over IPv6 231
AAA over IPv6 232
TACACS+ Over an IPv6 Transport 232
How to Configure TACACS+ over IPv6 232
Configuring the TACACS+ Server over IPv6 232
Specifying the Source Address in TACACS+ Packets 234

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
xiii

Contents

Configuring TACACS+ Server Group Options 234
Configuration Examples for TACACS+ over IPv6 235
Example: Configuring TACACS+ Server over IPv6 235
Additional References 236
Feature Information for TACACS+ over IPv6 237

CHAPTER 15

AAA Dead-Server Detection 239
Finding Feature Information 239
Prerequisites for AAA Dead-Server Detection 239
Restrictions for AAA Dead-Server Detection 240
Information About AAA Dead-Server Detection 240
Criteria for Marking a RADIUS Server As Dead 240
How to Configure AAA Dead-Server Detection 240
Configuring AAA Dead-Server Detection 240
Troubleshooting Tips 241
Verifying AAA Dead-Server Detection 242
Configuration Examples for AAA Dead-Server Detection 243
Configuring AAA Dead-Server Detection Example 243
debug aaa dead-criteria transactions Command Example 243
show aaa dead-criteria Command Example 243
Additional References 243
Feature Information for AAA Dead-Server Detection 245

CHAPTER 16

Login Password Retry Lockout 247
Finding Feature Information 247
Prerequisites for Login Password Retry Lockout 247
Restrictions for Login Password Retry Lockout 248
Information About Login Password Retry Lockout 248
Lock Out of a Local AAA User Account 248
How to Configure Login Password Retry Lockout 248
Configuring Login Password Retry Lockout 248
Unlocking a Login Locked-Out User 250
Clearing the Unsuccessful Login Attempts of a User 250
Monitoring and Maintaining Login Password Retry Lockout Status 251
Configuration Examples for Login Password Retry Lockout 252

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
xiv

Contents

Displaying the Login Password Retry Lockout Configuration Example 252
Additional References 253
Feature Information for Login Password Retry Lockout 254
Glossary 254

CHAPTER 17

MSCHAP Version 2 257
Finding Feature Information 257
Prerequisites for MSCHAP Version 2 258
Restrictions for MSCHAP Version 2 258
Information About MSCHAP Version 2 258
How to Configure MSCHAP Version 2 259
Configuring MSCHAP V2 Authentication 259
Verifying MSCHAP V2 Configuration 260
Configuring Password Aging for Crypto-Based Clients 261
Configuration Examples 263
Configuring Local Authentication Example 263
Configuring RADIUS Authentication Example 263
Configuring Password Aging with Crypto Authentication Example 263
Additional References 264
Feature Information for MSCHAP Version 2 265

CHAPTER 18

AAA Broadcast Accounting-Mandatory Response Support 267
Finding Feature Information 267
Prerequisites for AAA Broadcast Accounting-Mandatory Response Support 268
Restrictions for AAA Broadcast Accounting-Mandatory Response Support 268
Information About AAA Broadcast Accounting-Mandatory Response Support 268
AAA Broadcast Accounting 268
Simultaneous Broadcast and Wait Accounting 268
How AAA Broadcast Accounting is Supported for GGSN 269
Configuring Broadcast and Wait Accounting on the GGSN 269
Configuration Examples for AAA Broadcast Accounting-Mandatory Response Support 272
AAA Broadcast Accounting-Mandatory Response Support Example 272
Additional References 273
Feature Information for AAA Broadcast Accounting-Mandatory Response Support 274

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
xv

Contents

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
xvi

CHAPTER

Configuring Authentication
Authentication provides a method to identify users, which includes the login and password dialog, challenge
and response, messaging support, and encryption, depending on the selected security protocol. Authentication
is the way a user is identified prior to being allowed access to the network and network services.
• Finding Feature Information, page 1
• Prerequisites for Configuring Authentication, page 1
• Restrictions for Configuring Authentication, page 2
• Information About Configuring Authentication, page 2
• How to Configure AAA Authentication Methods, page 9
• Non-AAA Authentication Methods, page 40
• Authentication Examples, page 49
• Additional References, page 60
• Feature Information for Configuring Authentication, page 62

Finding Feature Information
Your software release may not support all the features documented in this module. For the latest caveats and
feature information, see Bug Search Tool and the release notes for your platform and software release. To
find information about the features documented in this module, and to see a list of the releases in which each
feature is supported, see the feature information table at the end of this module.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support.
To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.

Prerequisites for Configuring Authentication
The Cisco IOS XE implementation of authentication is divided into AAA Authentication and non-authentication
methods. Cisco recommends that, whenever possible, AAA security services be used to implement
authentication.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
1

Configuring Authentication
Restrictions for Configuring Authentication

Restrictions for Configuring Authentication
The number of AAA method lists that can be configured is 250.

Information About Configuring Authentication
The following sections describe how AAA authentication is configured by defining a named list of
authentication methods and then applying that list to various interfaces. This section also describes how AAA
authentication is handled by using RADIUS Change in Authorization (CoA):

Named Method Lists for Authentication
To configure AAA authentication, you must first define a named list of authentication methods, and then
apply that list to various interfaces. The method list defines the types of authentication to be performed and
the sequence in which they will be performed; it must be applied to a specific interface before any of the
defined authentication methods will be performed. The only exception is the default method list (which is
named “default”). The default method list is automatically applied to all interfaces except those that have a
named method list explicitly defined. A defined method list overrides the default method list.
A method list is a sequential list describing the authentication methods to be queried in order to authenticate
a user. Method lists enable you to designate one or more security protocols to be used for authentication, thus
ensuring a backup system for authentication in case the initial method fails. Cisco IOS XE software uses the
first listed method to authenticate users. If that method fails to respond, the Cisco IOS XE software selects
the next authentication method listed in the method list. This process continues until there is successful
communication with a listed authentication method, or all methods defined in the method list are exhausted.
It is important to note that the Cisco IOS XE software attempts authentication with the next listed authentication
method only when there is no response from the previous method. If authentication fails at any point in this
cycle--meaning that the security server or local username database responds by denying the user access--the
authentication process stops and no other authentication methods are attempted.

Note

The number of AAA method lists that can be configured is 250.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
2

Configuring Authentication
Named Method Lists for Authentication

RADIUS servers and T1 and T2 are TACACS+ servers. R1 and R2 make up the group of RADIUS servers.
T1 and T2 make up the group of TACACS+ servers.
Figure 1: Typical AAA Network Configuration

Using server groups, you can specify a subset of the configured server hosts and use them for a particular
service. For example, server groups allow you to define R1 and R2 as a server group, and define T1 and T2
as a separate server group. For example, you can specify R1 and T1 in the method list for authentication login,
while specifying R2 and T2 in the method list for PPP authentication.
Server groups also can include multiple host entries for the same server, as long as each entry has a unique
identifier. The combination of an IP address and a UDP port number creates a unique identifier, allowing
different ports to be individually defined as RADIUS hosts providing a specific AAA service. In other words,
this unique identifier enables RADIUS requests to be sent to different UDP ports on a server at the same IP
address. If two different host entries on the same RADIUS server are configured for the same service--for
example, authentication--the second host entry configured acts as failover backup to the first one. Using this
example, if the first host entry fails to provide accounting services, the network access server will try the
second host entry configured on the same device for accounting services. (The RADIUS host entries will be
tried in the order in which they are configured.)
For more information about configuring server groups and about configuring server groups based on Dialed
Number Identification Service (DNIS) numbers, refer to the “Configuring RADIUS” or “Configuring
TACACS+” chapter.

Method List Examples
Suppose the system administrator has decided on a security solution where all interfaces will use the same
authentication methods to authenticate PPP connections. In the RADIUS group, R1 is contacted first for
authentication information, then if there is no response, R2 is contacted. If R2 does not respond, T1 in the
TACACS+ group is contacted; if T1 does not respond, T2 is contacted. If all designated servers fail to respond,
authentication falls to the local username database on the access server itself. To implement this solution, the
system administrator would create a default method list by entering the following command:
aaa authentication ppp default group radius group tacacs+ local

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
3

Configuring Authentication
About RADIUS Change of Authorization

In this example, “default” is the name of the method list. The protocols included in this method list are listed
after the name, in the order they are to be queried. The default list is automatically applied to all interfaces.
When a remote user attempts to dial in to the network, the network access server first queries R1 for
authentication information. If R1 authenticates the user, it issues a PASS response to the network access server
and the user is allowed to access the network. If R1 returns a FAIL response, the user is denied access and
the session is terminated. If R1 does not respond, then the network access server processes that as an ERROR
and queries R2 for authentication information. This pattern would continue through the remaining designated
methods until the user is either authenticated or rejected, or until the session is terminated.
It is important to remember that a FAIL response is significantly different from an ERROR. A FAIL means
that the user has not met the criteria contained in the applicable authentication database to be successfully
authenticated. Authentication ends with a FAIL response. An ERROR means that the security server has not
responded to an authentication query. Because of this, no authentication has been attempted. Only when an
ERROR is detected will AAA select the next authentication method defined in the authentication method list.
Suppose the system administrator wants to apply a method list only to a particular interface or set of interfaces.
In this case, the system administrator creates a named method list and then applies this named list to the
applicable interfaces. The following example shows how the system administrator can implement an
authentication method that will be applied only to interface 3:
aaa authentication ppp default group radius group tacacs+ local
aaa authentication ppp apple group radius group tacacs+ local none
interface async 3
ppp authentication chap apple

In this example, “apple” is the name of the method list, and the protocols included in this method list are listed
after the name in the order in which they are to be performed. After the method list has been created, it is
applied to the appropriate interface. Note that the method list name (apple) in both the AAAand PPP
authentication commands must match.
In the following example, the system administrator uses server groups to specify that only R2 and T2 are valid
servers for PPP authentication. To do this, the administrator must define specific server groups whose members
are R2 (172.16.2.7) and T2 (172.16.2.77), respectively. In this example, the RADIUS server group “rad2only”
is defined as follows using the aaa group server command:
aaa group server radius rad2only
server 172.16.2.7

The TACACS+ server group “tac2only” is defined as follows using the aaa group server command:
aaa group server tacacs+ tac2only
server 172.16.2.77

The administrator then applies PPP authentication using the server groups. In this example, the default methods
list for PPP authentication follows this order: group rad2only, group tac2only, and local:
aaa authentication ppp default group rad2only group tac2only local

About RADIUS Change of Authorization
A standard RADIUS interface is typically used in a pulled model, in which the request originates from a
device attached to a network and the response is sent from the queried servers. The Cisco software supports
the RADIUS CoA request defined in RFC 5176 that is used in a pushed model, in which the request originates
from the external server to the device attached to the network, and enables the dynamic reconfiguring of
sessions from external authentication, authorization, and accounting (AAA) or policy servers.
Use the following per-session CoA requests:

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
4

Configuring Authentication
About RADIUS Change of Authorization

• Session reauthentication
• Session termination
• Session termination with port shutdown
• Session termination with port bounce
• Security and Password
• Accounting

CoA Requests
CoA requests, as described in RFC 5176, are used in a pushed model to allow for session identification, host
reauthentication, and session termination. The model comprises one request (CoA-Request) and two possible
response codes:
• CoA acknowledgment (ACK) [CoA-ACK]
• CoA non-acknowledgment (NAK) [CoA-NAK]
The request is initiated from a CoA client (typically a RADIUS or policy server) and directed to the device
that acts as a listener.

RFC 5176 Compliance
The Disconnect Request message, which is also referred to as Packet of Disconnect (POD), is supported by
the device for a session termination.
The following table shows the IETF attributes that are supported for the RADIUS Change of Authorization
(CoA) feature.
Table 1: Supported IETF Attributes

Attribute Number

Attribute Name

State

Calling-Station-ID

Acct-Session-ID

Message-Authenticator

101

Error-Cause

The following table shows the possible values for the Error-Cause attribute.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
5

Configuring Authentication
About RADIUS Change of Authorization

Table 2: Error-Cause Values

Value

Explanation

201

Residual Session Context Removed

202

Invalid EAP Packet (Ignored)

401

Unsupported Attribute

402

Missing Attribute

403

NAS Identification Mismatch

404

Invalid Request

405

Unsupported Service

406

Unsupported Extension

407

Invalid Attribute Value

501

Administratively Prohibited

502

Request Not Routable (Proxy)

503

Session Context Not Found

504

Session Context Not Removable

505

Other Proxy Processing Error

506

Resources Unavailable

507

Request Initiated

508

Multiple Session Selection Unsupported

CoA Request Response Code
The CoA Request Response code can be used to issue a command to the device. The supported commands
are listed in the “CoA Request Commands” section.
The packet format for a CoA Request Response code as defined in RFC 5176 consists of the following fields:
Code, Identifier, Length, Authenticator, and Attributes in the Type:Length:Value (TLV) format.
The Attributes field is used to carry Cisco VSAs.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
6

Configuring Authentication
About RADIUS Change of Authorization

Session Identification
For disconnect and CoA requests targeted at a particular session, the device locates the session based on one
or more of the following attributes:
• Acct-Session-Id (IETF attribute #44)
• Audit-Session-Id (Cisco vendor-specific attribute (VSA))
• Calling-Station-Id (IETF attribute #31, which contains the host MAC address)
Unless all session identification attributes included in the CoA message match the session, the device returns
a Disconnect-NAK or CoA-NAK with the “Invalid Attribute Value” error-code attribute.

Note

A CoA NAK message is not sent for all CoA requests with a key mismatch. The message is sent only for
the first three requests for a client. After that, all the packets from that client are dropped. When there is
a key mismatch, the response authenticator sent with the CoA NAK message is calculated from a dummy
key value.

CoA ACK Response Code
If an authorization state is changed successfully, a positive acknowledgment (ACK) is sent. The attributes
returned within a CoA ACK can vary based on the CoA Request.

CoA NAK Response Code
A negative acknowledgment (NAK) indicates a failure to change the authorization state and can include
attributes that indicate the reason for the failure.

CoA Request Commands
The commands supported on the device are shown in the table below. All CoA commands must include the
session identifier between the device and the CoA client.
Table 3: CoA Request Commands Supported on the Device

Command

Cisco VSA

Bounce host port

Cisco:Avpair=“subscriber:command=bounce-host-port”

Disable host port

Cisco:Avpair=“subscriber:command=disable-host-port”

Reauthenticate host

Cisco:Avpair=“subscriber:command=reauthenticate”

Terminate session

This is a standard disconnect request that does not require a VSA

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
7

Configuring Authentication
About RADIUS Change of Authorization

Session Reauthentication
To initiate session reauthentication, the authentication, authorization, and accounting (AAA) server sends a
standard CoA-Request message that contains a Cisco VSA and one or more session identification attributes.
The Cisco VSA is in the form of Cisco:Avpair=“subscriber:command=reauthenticate”.
The current session state determines the device’s response to the message in the following scenarios:
• If the session is currently authenticated by IEEE 802.1x, the device responds by sending an Extensible
Authentication Protocol over LAN (EAPoL)-RequestId message to the server.
• If the session is currently authenticated by MAC authentication bypass (MAB), the device sends an
access request to the server, passing the same identity attributes used for the initial successful
authentication.
• If session authentication is in progress when the device receives the command, the device terminates
the process and restarts the authentication sequence, starting with the method configured to be attempted
first.

Session Termination
A CoA Disconnect-Request terminates the session without disabling the host port. CoA Disconnect-Request
termination causes reinitialization of the authenticator state machine for the specified host, but does not restrict
the host’s access to the network. If the session cannot be located, the device returns a Disconnect-NAK message
with the “Session Context Not Found” error-code attribute. If the session is located, the device terminates the
session. After the session has been completely removed, the device returns a Disconnect-ACK message.
To restrict a host’s access to the network, use a CoA Request with the
Cisco:Avpair=“subscriber:command=disable-host-port” VSA. This command is useful when a host is known
to cause problems on the network and network access needs to be immediately blocked for the host. If you
want to restore network access on the port, reenable it using a non-RADIUS mechanism.

CoA Request Disable Host Port
The RADIUS server CoA disable port command administratively shuts down the authentication port that is
hosting a session, resulting in session termination. This command is useful when a host is known to cause
problems on the network and network access needs to be immediately blocked for the host. If you want to
restore network access on the port, reenable it using a non-RADIUS mechanism. This command is carried in
a standard CoA-Request message that has the following VSA:
Cisco:Avpair=“subscriber:command=disable-host-port”
Because this command is session-oriented, it must be accompanied by one or more of the session identification
attributes described in the “Session Identification” section. If the device cannot locate the session, it returns a
CoA-NAK message with the “Session Context Not Found” error-code attribute. If the device locates the
session, it disables the hosting port and returns a CoA-ACK message.
If the device fails before returning a CoA-ACK to the client, the process is repeated on the new active device
when the request is re-sent from the client. If the device fails after returning a CoA-ACK message to the client
but before the operation is complete, the operation is restarted on the new active device.
To ignore the RADIUS server CoA disable port command, see the “Configuring the Device to Ignore Bounce
and Disable RADIUS CoA Requests” section.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
8

Configuring Authentication
Domain Stripping

CoA Request Bounce Port
A RADIUS server CoA bounce port sent from a RADIUS server can cause a link flap on an authentication
port, which triggers DHCP renegotiation from one or more hosts connected to this port. This incident can
occur when there is a VLAN change and the endpoint is a device (such as a printer) that does not have a
mechanism to detect a change on this authentication port. The CoA bounce port is carried in a standard
CoA-Request message that contains the following VSA:
Cisco:Avpair=“subscriber:command=bounce-host-port”
Because this command is session-oriented, it must be accompanied by one or more of the session identification
attributes described in the Session Identification. If the session cannot be located, the device returns a CoA-NAK
message with the “Session Context Not Found” error-code attribute. If the session is located, the device disables
the hosting port for a period of 10 seconds, reenables it (port-bounce), and returns a CoA-ACK.
To ignore the RADIUS server CoA bounce port, see the “Configuring the Device to Ignore Bounce and Disable
RADIUS CoA Requests” section.

Domain Stripping
You can remove the domain name from the username received at the global level by using the radius-server
domain-stripping command. When the radius-server domain-stripping command is configured, all the
AAA requests with “user@example.com” go to the remote RADIUS server with the reformatted username
“user.” The domain name is removed from the request.

Note

Domain stripping will not be done in a TACACS configuration.
The AAA Broadcast Accounting feature allows accounting information to be sent to multiple AAA servers
at the same time, that is, accounting information can be broadcast to one or more AAA servers simultaneously.
This functionality allows you to send accounting information to private and public AAA servers. It also
provides redundant billing information for voice applications.
The Domain Stripping feature allows domain stripping to be configured at the server group level.
Per-server group configuration overrides the global configuration. If domain stripping is not enabled globally,
but it is enabled in a server group, then it is enabled only for that server group. Also, if virtual routing and
forwarding (VRF)-specific domain stripping is configured globally and in a server group for a different VRF,
domain stripping is enabled in both the VRFs. VRF configurations are taken from server-group configuration
mode. If server-group configurations are disabled in global configuration mode but are available in server-group
configuration mode, all configurations in server-group configuration mode are applicable.
After the domain stripping and broadcast accounting are configured, you can create separate accounting
records as per the configurations.

How to Configure AAA Authentication Methods
Note

AAA features are not available until you enable AAA globally using the aaa new-model command.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
9

Configuring Authentication
Configuring Login Authentication Using AAA

For authentication configuration examples using the commands in this chapter, refer to the Authentication
Examples.

Configuring Login Authentication Using AAA
The AAA security services facilitate a variety of login authentication methods. Use the aaa authentication
logincommand to enable AAA authentication no matter which of the supported login authentication methods
you decide to use. With the aaa authentication logincommand, you create one or more lists of authentication
methods that are tried at login. These lists are applied using the login authentication line configuration
command.
To configure login authentication by using AAA, use the following commands beginning in global configuration
mode:

SUMMARY STEPS
1. Router(config)# aaa new-model
2. Router(config)# aaa authentication login{default | list-name} method1[method2...]
3. Router(config)# line [aux | console | tty | vty] line-number [ending-line-number]
4. Router(config-line)# login authentication

DETAILED STEPS
Command or Action

Purpose

Step 1

Router(config)# aaa new-model

Enables AAA globally.

Step 2

Router(config)# aaa authentication login{default |
list-name} method1[method2...]

Creates a local authentication list.

Step 3

Router(config)# line [aux | console | tty | vty] line-number Enters line configuration mode for the lines to which
you want to apply the authentication list.
[ending-line-number]

Step 4

Router(config-line)# login authentication

Applies the authentication list to a line or set of lines.

Example:
{default |

list-name}

What to Do Next
The list-name is a character string used to name the list you are creating. The method argument refers to the
actual method the authentication algorithm tries. The additional methods of authentication are used only if
the previous method returns an error, not if it fails. To specify that the authentication should succeed even if
all methods return an error, specify none as the final method in the command line.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
10

Configuring Authentication
Configuring Login Authentication Using AAA

For example, to specify that authentication should succeed even if (in this example) the TACACS+ server
returns an error, enter the following command:
aaa authentication login default group tacacs+ none

Note

Because the none keyword enables any user logging in to successfully authenticate, it should be used only
as a backup method of authentication.
To create a default list that is used when a named list is not specified in the login authentication command,
use the default keyword followed by the methods that are to be used in default situations. The default method
list is automatically applied to all interfaces.
For example, to specify RADIUS as the default method for user authentication during login, enter the following
command:
aaa authentication login default group radius

The table below lists the supported login authentication methods.
Table 4: AAA Authentication Login Methods

Keyword

Description

enable

Uses the enable password for authentication.

krb5

Uses Kerberos 5 for authentication.

krb5-telnet

Uses Kerberos 5 Telnet authentication protocol when
using Telnet to connect to the router. If selected, this
keyword must be listed as the first method in the
method list.

line

Uses the line password for authentication.

local

Uses the local username database for authentication.

local-case

Uses case-sensitive local username authentication.

none

Uses no authentication.

group radius

Uses the list of all RADIUS servers for authentication.

group tacacs+

Uses the list of all TACACS+ servers for
authentication.

group group-name

Uses a subset of RADIUS or TACACS+ servers for
authentication as defined by the aaa group server
radius or aaa group server tacacs+ command.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
11

Configuring Authentication
Configuring Login Authentication Using AAA

Note

The login command only changes username and privilege level but does not execute a shell; therefore
autocommands will not be executed. To execute autocommands under this circumstance, you need to
establish a Telnet session back into the router (loop-back). Make sure that the router has been configured
for secure Telnet sessions if you choose to implement autocommands this way.

Login Authentication Using Enable Password
Use the aaa authentication logincommand with the enable method keyword to specify the enable password
as the login authentication method. For example, to specify the enable password as the method of user
authentication at login when no other method list has been defined, enter the following command:
aaa authentication login default enable

Before you can use the enable password as the login authentication method, you need to define the enable
password. For more information about defining enable passwords, refer to the chapter “Configuring Passwords
and Privileges.”

Login Authentication Using Kerberos
Authentication via Kerberos is different from most other authentication methods: the user’s password is never
sent to the remote access server. Remote users logging in to the network are prompted for a username. If the
key distribution center (KDC) has an entry for that user, it creates an encrypted ticket granting ticket (TGT)
with the password for that user and sends it back to the router. The user is then prompted for a password, and
the router attempts to decrypt the TGT with that password. If it succeeds, the user is authenticated and the
TGT is stored in the user’s credential cache on the router.
While krb5 does use the KINIT program, a user does not need to run the KINIT program to get a TGT to
authenticate to the router. This is because KINIT has been integrated into the login procedure in the Cisco
IOS XE implementation of Kerberos.
Use the aaa authentication logincommand with the krb5method keyword to specify Kerberos as the login
authentication method. For example, to specify Kerberos as the method of user authentication at login when
no other method list has been defined, enter the following command:
aaa authentication login default krb5

Before you can use Kerberos as the login authentication method, you need to enable communication with the
Kerberos security server. For more information about establishing communication with a Kerberos server,
refer to the chapter “Configuring Kerberos.”

Login Authentication Using Line Password
Use the aaa authentication logincommand with the line method keyword to specify the line password as the
login authentication method. For example, to specify the line password as the method of user authentication
at login when no other method list has been defined, enter the following command:
aaa authentication login default line

Before you can use a line password as the login authentication method, you need to define a line password.
For more information about defining line passwords, refer to the Configuring Line Password Protection.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
12

Configuring Authentication
Configuring Login Authentication Using AAA

Login Authentication Using Local Password
Use the aaa authentication logincommand with the local method keyword to specify that the Cisco router
or access server will use the local username database for authentication. For example, to specify the local
username database as the method of user authentication at login when no other method list has been defined,
enter the following command:
aaa authentication login default local

For information about adding users into the local username database, refer to the Establishing Username
Authentication.

Login Authentication Using Group RADIUS
Use the aaa authentication logincommand with the group radius method to specify RADIUS as the login
authentication method. For example, to specify RADIUS as the method of user authentication at login when
no other method list has been defined, enter the following command:
aaa authentication login default group radius

Before you can use RADIUS as the login authentication method, you need to enable communication with the
RADIUS security server. For more information about establishing communication with a RADIUS server,
refer to the chapter “Configuring RADIUS.”

Configuring RADIUS Attribute 8 in Access Requests
After you have used the aaa authentication login command to specify RADIUS and your login host has been
configured to request its IP address from the NAS, you can send attribute 8 (Framed-IP-Address) in
access-request packets by using the radius-server attribute 8 include-in-access-req command in global
configuration mode. This command makes it possible for NAS to provide the RADIUS server a hint of the
user IP address in advance for user authentication. For more information about attribute 8, refer to the appendix
“RADIUS Attributes” at the end of the book.

Login Authentication Using Group TACACS
Use the aaa authentication logincommand with the group tacacs+ method to specify TACACS+ as the login
authentication method. For example, to specify TACACS+ as the method of user authentication at login when
no other method list has been defined, enter the following command:
aaa authentication login default group tacacs+

Before you can use TACACS+ as the login authentication method, you need to enable communication with
the TACACS+ security server. For more information about establishing communication with a TACACS+
server, refer to the chapter “Configuring TACACS+.”

Login Authentication Using group group-name
Use the aaa authentication logincommand with the group group-name method to specify a subset of RADIUS
or TACACS+ servers to use as the login authentication method. To specify and define the group name and

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
13

Configuring Authentication
Configuring PPP Authentication Using AAA

the members of the group, use the aaa group server command. For example, use the aaa group server
command to first define the members of group loginrad:
aaa group server radius loginrad
server 172.16.2.3
server 172.16.2 17
server 172.16.2.32

This command specifies RADIUS servers 172.16.2.3, 172.16.2.17, and 172.16.2.32 as members of the group
loginrad.
To specify group loginrad as the method of user authentication at login when no other method list has been
defined, enter the following command:
aaa authentication login default group loginrad

Before you can use a group name as the login authentication method, you need to enable communication with
the RADIUS or TACACS+ security server. For more information about establishing communication with a
RADIUS server, refer to the chapter “Configuring RADIUS.” For more information about establishing
communication with a TACACS+ server, refer to the chapter “Configuring TACACS+.”

Configuring PPP Authentication Using AAA
Many users access network access servers through dialup via async or ISDN. Dialup via async or ISDN
bypasses the CLI completely; instead, a network protocol (such as PPP or ARA) starts as soon as the connection
is established.
The AAA security services facilitate a variety of authentication methods for use on serial interfaces running
PPP. Use the aaa authentication pppcommand to enable AAA authentication no matter which of the supported
PPP authentication methods you decide to use.
To configure AAA authentication methods for serial lines using PPP, use the following commands in global
configuration mode:

SUMMARY STEPS
1. Router(config)# aaa new-model
2. Router(config)# aaa authentication ppp{default | list-name} method1[method2...]
3. Router(config)# interface interface-type interface-number
4. Router(config-if)# ppp authentication {protocol1 [protocol2...]} [if-needed] {default | list-name} [callin]
[one-time][optional]

DETAILED STEPS
Command or Action

Purpose

Step 1

Router(config)# aaa new-model

Enables AAA globally.

Step 2

Router(config)# aaa authentication ppp{default Creates a local authentication list.
| list-name} method1[method2...]

Step 3

Router(config)# interface interface-type
interface-number

Enters interface configuration mode for the interface to which you
want to apply the authentication list.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
14

Configuring Authentication
Configuring PPP Authentication Using AAA

Command or Action
Step 4

Purpose

Router(config-if)# ppp authentication {protocol1 Applies the authentication list to a line or set of lines. In this
[protocol2...]} [if-needed] {default | list-name} command, protocol1 and protocol2 represent the following
protocols: CHAP, MS-CHAP, and PAP. PPP authentication is
[callin] [one-time][optional]
attempted first using the first authentication method, specified by
protocol1. If protocol1 is unable to establish authentication, the
next configured protocol is used to negotiate authentication.

What to Do Next
With the aaa authentication pppcommand, you create one or more lists of authentication methods that are
tried when a user tries to authenticate via PPP. These lists are applied using the ppp authentication line
configuration command.
To create a default list that is used when a named list is not specified in the ppp authentication command,
use the default keyword followed by the methods you want used in default situations.
For example, to specify the local username database as the default method for user authentication, enter the
following command:
aaa authentication ppp default local

The list-name is any character string used to name the list you are creating. The method argument refers to
the actual method the authentication algorithm tries. The additional methods of authentication are used only
if the previous method returns an error, not if it fails. To specify that the authentication should succeed even
if all methods return an error, specify none as the final method in the command line.
For example, to specify that authentication should succeed even if (in this example) the TACACS+ server
returns an error, enter the following command:
aaa authentication ppp default group tacacs+ none

Note

Because none allows all users logging in to authenticate successfully, it should be used as a backup method
of authentication.
The table below lists the supported login authentication methods.
Table 5: AAA Authentication PPP Methods

Keyword

Description

if-needed

Does not authenticate if user has already been
authenticated on a TTY line.

krb5

Uses Kerberos 5 for authentication (can only be used
for PAP authentication).

local

Uses the local username database for authentication.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
15

Configuring Authentication
Configuring PPP Authentication Using AAA

Keyword

Description

local-case

Uses case-sensitive local username authentication.

none

Uses no authentication.

group radius

Uses the list of all RADIUS servers for authentication.

group tacacs+

Uses the list of all TACACS+ servers for
authentication.

group group-name

Uses a subset of RADIUS or TACACS+ servers for
authentication as defined by the aaa group server
radius or aaa group server tacacs+ command.

PPP Authentication Using Kerberos
Use the aaa authentication pppcommand with the krb5method keyword to specify Kerberos as the
authentication method for use on interfaces running PPP. For example, to specify Kerberos as the method of
user authentication when no other method list has been defined, enter the following command:
aaa authentication ppp default krb5

Before you can use Kerberos as the PPP authentication method, you need to enable communication with the
Kerberos security server. For more information about establishing communication with a Kerberos server,
refer to the chapter “Configuring Kerberos”.

Note

Kerberos login authentication works only with PPP PAP authentication.

PPP Authentication Using Local Password
Use the aaa authentication pppcommand with the method keyword local to specify that the Cisco router or
access server will use the local username database for authentication. For example, to specify the local username
database as the method of authentication for use on lines running PPP when no other method list has been
defined, enter the following command:
aaa authentication ppp default local

For information about adding users into the local username database, refer to the Establishing Username
Authentication.

PPP Authentication Using Group RADIUS
Use the aaa authentication pppcommand with the group radius method to specify RADIUS as the login
authentication method. For example, to specify RADIUS as the method of user authentication at login when
no other method list has been defined, enter the following command:
aaa authentication ppp default group radius

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
16

Configuring Authentication
Configuring AAA Scalability for PPP Requests

Before you can use RADIUS as the PPP authentication method, you need to enable communication with the
RADIUS security server. For more information about establishing communication with a RADIUS server,
refer to the chapter “Configuring RADIUS.”

Configuring RADIUS Attribute 44 in Access Requests
After you have used the aaa authentication ppp command with the group radius method to specify RADIUS
as the login authentication method, you can configure your device to send attribute 44 (Acct-Session-ID) in
access-request packets by using the radius-server attribute 44 include-in-access-req command in global
configuration mode. This command allows the RADIUS daemon to track a call from the beginning to the end.

PPP Authentication Using Group TACACS
Use the aaa authentication pppcommand with the group tacacs+ method to specify TACACS+ as the login
authentication method. For example, to specify TACACS+ as the method of user authentication at login when
no other method list has been defined, enter the following command:
aaa authentication ppp default group tacacs+

Before you can use TACACS+ as the PPP authentication method, you need to enable communication with
the TACACS+ security server. For more information about establishing communication with a TACACS+
server, refer to the chapter “Configuring TACACS+.”

PPP Authentication Using group group-name
Use the aaa authentication pppcommand with the group group-name method to specify a subset of RADIUS
or TACACS+ servers to use as the login authentication method. To specify and define the group name and
the members of the group, use the aaa group server command. For example, use the aaa group server
command to first define the members of group ppprad:
aaa group server radius ppprad
server 172.16.2.3
server 172.16.2 17
server 172.16.2.32

This command specifies RADIUS servers 172.16.2.3, 172.16.2.17, and 172.16.2.32 as members of the group
ppprad.
To specify group ppprad as the method of user authentication at login when no other method list has been
defined, enter the following command:
aaa authentication ppp default group ppprad

Before you can use a group name as the PPP authentication method, you need to enable communication with
the RADIUS or TACACS+ security server. For more information about establishing communication with a
RADIUS server, refer to the chapter “Configuring RADIUS”. For more information about establishing
communication with a TACACS+ server, refer to the chapter “Configuring TACACS+.”

Configuring AAA Scalability for PPP Requests
You can configure and monitor the number of background processes allocated by the PPP manager in the
network access server (NAS) to deal with AAA authentication and authorization requests. The AAA Scalability

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
17

Configuring Authentication
Configuring ARAP Authentication Using AAA

feature enables you to configure the number of processes used to handle AAA requests for PPP, thus increasing
the number of users that can be simultaneously authenticated or authorized.
To allocate a specific number of background processes to handle AAA requests for PPP, use the following
command in global configuration mode:
Command
Router(config)#

Purpose
aaa processes

Allocates a specific number of background processes
to handle AAA authentication and authorization
requests for PPP.

number

The argument number defines the number of background processes earmarked to process AAA authentication
and authorization requests for PPP and can be configured for any value from 1 to 2147483647. Because of
the way the PPP manager handles requests for PPP, this argument also defines the number of new users that
can be simultaneously authenticated. This argument can be increased or decreased at any time.

Note

Allocating additional background processes can be expensive. You should configure the minimum number
of background processes capable of handling the AAA requests for PPP.

Configuring ARAP Authentication Using AAA
Using the aaa authentication arap command, you can create one or more lists of authentication methods
that are tried when AppleTalk Remote Access Protocol (ARAP) users attempt to log in to the device. These
lists are used with the arap authentication line configuration command.
Use the following commands starting in global configuration mode:

SUMMARY STEPS
1. Device(config)# aaa new-model
2. Device(config)# aaa authentication arap
3. Device(config)# line number
4. Device(config-line)# autoselect arap
5. Device(config-line)# autoselect during-login
6. Device(config-line)# arap authentication list-name
7. Device(config-line)# end

DETAILED STEPS
Command or Action

Purpose

Step 1

Device(config)# aaa new-model

Enables AAA globally.

Step 2

Device(config)# aaa authentication arap

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
18

Configuring Authentication
Configuring ARAP Authentication Using AAA

Command or Action

Purpose

Example:

Enables authentication for ARAP users.
Step 3

Device(config)# line number

(Optional) Changes to line configuration mode.

Step 4

Device(config-line)# autoselect arap

(Optional) Enables autoselection of ARAP.

Step 5

Device(config-line)# autoselect during-login

(Optional) Starts the ARAP session automatically at user
login.

Step 6

Device(config-line)# arap authentication list-name (Optional—not needed if default is used in the aaa
authentication arap command) Enables TACACS+
authentication for ARAP on a line.

Step 7

Device(config-line)# end

Returns to the privileged EXEC mode.

What to Do Next
The list-name is any character string used to name the list you are creating. The method argument refers to
the actual list of methods the authentication algorithm tries, in the sequence entered.
To create a default list that is used when a named list is not specified in the arap authentication command,
use the default keyword followed by the methods you want to use in default situations.
The additional methods of authentication are used only if the previous method returns an error, not if it fails.
To specify that the authentication should succeed even if all methods return an error, specify none as the final
method in the command line.

Note

Because none allows all users logging in to be authenticated, it should be used as a backup method of
authentication.
The following table lists the supported login authentication methods.
Table 6: AAA Authentication ARAP Methods

Keyword

Description

auth-guest

Allows guest logins only if the user has already
logged in to EXEC mode.

guest

Allows guest logins.

line

Uses the line password for authentication.

local

Uses the local username database for authentication.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
19

Configuring Authentication
Configuring ARAP Authentication Using AAA

Keyword

Description

local-case

Uses case-sensitive local username authentication.

group radius

Uses the list of all RADIUS servers for authentication.

group tacacs+

Uses the list of all TACACS+ servers for
authentication.

group group-name

Uses a subset of RADIUS or TACACS+ servers for
authentication as defined by the aaa group server
radius or aaa group server tacacs+ command.

For example, to create a default AAA authentication method list used with ARAP, use the following command:
aaa authentication arap default if-needed none

To create the same authentication method list for ARAP and name the list MIS-access, use the following
command:
aaa authentication arap MIS-access if-needed none

This section includes the following sections:

ARAP Authentication Allowing Authorized Guest Logins
Use the aaa authentication arapcommand with the auth-guest keyword to allow guest logins only if the
user has already successfully logged in to the EXEC. This method must be the first listed in the ARAP
authentication method list but it can be followed by other methods if it does not succeed. For example, to
allow all authorized guest logins--meaning logins by users who have already successfully logged in to the
EXEC--as the default method of authentication, using RADIUS only if that method fails, enter the following
command:
aaa authentication arap default auth-guest group radius

Note

By default, guest logins through ARAP are disabled when you initialize AAA. To allow guest logins, you
must use the aaa authentication arap command with either the guest or the auth-guest keyword.

ARAP Authentication Allowing Guest Logins
Use the aaa authentication arapcommand with the guest keyword to allow guest logins. This method must
be the first listed in the ARAP authentication method list but it can be followed by other methods if it does
not succeed. For example, to allow all guest logins as the default method of authentication, using RADIUS
only if that method fails, enter the following command:
aaa authentication arap default guest group radius

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
20

Configuring Authentication
Configuring ARAP Authentication Using AAA

ARAP Authentication Using Line Password
Use the aaa authentication arapcommand with the method keyword line to specify the line password as the
authentication method. For example, to specify the line password as the method of ARAP user authentication
when no other method list has been defined, enter the following command:
aaa authentication arap default line

Before you can use a line password as the ARAP authentication method, you need to define a line password.
For more information about defining line passwords, refer to the section Configuring Line Password Protection
in this chapter.

ARAP Authentication Using Local Password
Use the aaa authentication arapcommand with the methodkeyword local to specify that the Cisco router or
access server will use the local username database for authentication. For example, to specify the local username
database as the method of ARAP user authentication when no other method list has been defined, enter the
following command:
aaa authentication arap default local

For information about adding users to the local username database, refer to the Establishing Username
Authentication.

ARAP Authentication Using Group RADIUS
Use the aaa authentication arapcommand with the group radius method to specify RADIUS as the ARAP
authentication method. For example, to specify RADIUS as the method of user authentication at login when
no other method list has been defined, enter the following command:
aaa authentication arap default group radius

Before you can use RADIUS as the ARAP authentication method, you need to enable communication with
the RADIUS security server. For more information about establishing communication with a RADIUS server,
refer to the chapter “Configuring RADIUS.”

ARAP Authentication Using Group TACACS
Use the aaa authentication arapcommand with the group tacacs+ method to specify TACACS+ as the
ARAP authentication method. For example, to specify TACACS+ as the method of user authentication at
login when no other method list has been defined, enter the following command:
aaa authentication arap default group tacacs+

Before you can use TACACS+ as the ARAP authentication method, you need to enable communication with
the TACACS+ security server. For more information about establishing communication with a TACACS+
server, refer to the chapter “Configuring TACACS+.”

ARAP Authentication Using Group group-name
Use the aaa authentication arapcommand with the group group-name method to specify a subset of RADIUS
or TACACS+ servers to use as the ARAP authentication method. To specify and define the group name and

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
21

Configuring Authentication
Configuring NASI Authentication Using AAA

the members of the group, use the aaa group server command. For example, use the aaa group
servercommand to first define the members of group araprad:
aaa group server radius araprad
server 172.16.2.3
server 172.16.2 17
server 172.16.2.32

This command specifies RADIUS servers 172.16.2.3, 172.16.2.17, and 172.16.2.32 as members of the group
araprad.
To specify group araprad as the method of user authentication at login when no other method list has been
defined, enter the following command:
aaa authentication arap default group araprad

Before you can use a group name as the ARAP authentication method, you need to enable communication
with the RADIUS or TACACS+ security server. For more information about establishing communication
with a RADIUS server, refer to the chapter “Configuring RADIUS.” For more information about establishing
communication with a TACACS+ server, refer to the chapter “Configuring TACACS+.”

Configuring NASI Authentication Using AAA
Using the aaa authentication nasi command, you can create one or more lists of authentication methods that
are tried when NetWare Asynchronous Services Interface (NASI) users attempt to log in to the device. These
lists are used with the nasi authentication line configuration command.
To configure NASI authentication using AAA, use the following commands starting in global configuration
mode:

SUMMARY STEPS
1. Device(config)# aaa new-model
2. Device(config)# aaa authentication nasi
3. Device(config)# line number
4. Device(config-line)# nasi authentication list-name
5. Device(config-line)# end

DETAILED STEPS
Command or Action

Purpose

Step 1

Device(config)# aaa new-model

Enables AAA globally.

Step 2

Device(config)# aaa authentication nasi

Enables authentication for NASI users.

Example:

Step 3

Device(config)# line number

(Optional--not needed if default is used in the aaa
authentication nasi command) Enters line configuration mode.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
22

Configuring Authentication
Configuring NASI Authentication Using AAA

Command or Action

Purpose

Step 4

Device(config-line)# nasi authentication
list-name

(Optional--not needed if default is used in the aaa
authentication nasi command) Enables authentication for NASI
on a line.

Step 5

Device(config-line)# end

Returns to the privileged EXEC mode.

What to Do Next
The list-name is any character string used to name the list you are creating. The method argument refers to
the actual list of methods that the authentication algorithm tries, in the sequence entered.
To create a default list that is used when a named list is not specified in the aaa authentication nasi command,
use the default keyword followed by the methods you want to use in default situations.
The additional methods of authentication are used only if the previous method returns an error, not if it fails.
To specify that the authentication should succeed even if all methods return an error, specify none as the final
method in the command line.

Note

Because none allows all users logging in to be authenticated, it should be used as a backup method of
authentication.
The table below lists the supported NASI authentication methods.
Table 7: AAA Authentication NASI Methods

Keyword

Description

enable

Uses the enable password for authentication.

line

Uses the line password for authentication.

local

Uses the local username database for authentication.

local-case

Uses case-sensitive local username authentication.

none

Uses no authentication.

group radius

Uses the list of all RADIUS servers for authentication.

group tacacs+

Uses the list of all TACACS+ servers for
authentication.

group group-name

Uses a subset of RADIUS or TACACS+ servers for
authentication as defined by the aaa group server
radius or aaa group server tacacs+ command.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
23

Configuring Authentication
Configuring NASI Authentication Using AAA

NASI Authentication Using Enable Password
Use the aaa authentication nasi command with the keyword enable to specify the enable password as the
authentication method. For example, to specify the enable password as the method of NASI user authentication
when no other method list has been defined, use the following command:
aaa authentication nasi default enable

Before you can use the enable password as the authentication method, you need to define the enable password.
For more information about defining enable passwords, refer to the chapter “Configuring Passwords and
Privileges.”

NASI Authentication Using Line Password
Use the aaa authentication nasicommand with the method keyword line to specify the line password as the
authentication method. For example, to specify the line password as the method of NASI user authentication
when no other method list has been defined, enter the following command:
aaa authentication nasi default line

Before you can use a line password as the NASI authentication method, you need to define a line password.
For more information about defining line passwords, refer to the Configuring Line Password Protection.

NASI Authentication Using Local Password
Use the aaa authentication nasicommand with the method keyword local to specify that the Cisco router or
access server will use the local username database for authentication information. For example, to specify the
local username database as the method of NASI user authentication when no other method list has been
defined, enter the following command:
aaa authentication nasi default local

For information about adding users to the local username database, refer to the Establishing Username
Authentication.

NASI Authentication Using Group RADIUS
Use the aaa authentication nasicommand with the group radius method to specify RADIUS as the NASI
authentication method. For example, to specify RADIUS as the method of NASI user authentication when
no other method list has been defined, enter the following command:
aaa authentication nasi default group radius

Before you can use RADIUS as the NASI authentication method, you need to enable communication with
the RADIUS security server. For more information about establishing communication with a RADIUS server,
refer to the chapter “Configuring RADIUS.”

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
24

Configuring Authentication
Specifying the Amount of Time for Login Input

NASI Authentication Using Group TACACS
Use the aaa authentication nasicommand with the group tacacs+ method keyword to specify TACACS+
as the NASI authentication method. For example, to specify TACACS+ as the method of NASI user
authentication when no other method list has been defined, enter the following command:
aaa authentication nasi default group tacacs+

Before you can use TACACS+ as the authentication method, you need to enable communication with the
TACACS+ security server. For more information about establishing communication with a TACACS+ server,
refer to the chapter “Configuring TACACS+.”

NASI Authentication Using group group-name
Use the aaa authentication nasicommand with the group group-name method to specify a subset of RADIUS
or TACACS+ servers to use as the NASI authentication method. To specify and define the group name and
the members of the group, use the aaa group server command. For example, use the aaa group
servercommand to first define the members of group nasirad:
aaa group server radius nasirad
server 172.16.2.3
server 172.16.2 17
server 172.16.2.32

This command specifies RADIUS servers 172.16.2.3, 172.16.2.17, and 172.16.2.32 as members of the group
nasirad.
To specify group nasirad as the method of user authentication at login when no other method list has been
defined, enter the following command:
aaa authentication nasi default group nasirad

Before you can use a group name as the NASI authentication method, you need to enable communication
with the RADIUS or TACACS+ security server. For more information about establishing communication
with a RADIUS server, refer to the chapter “Configuring RADIUS”. For more information about establishing
communication with a TACACS+ server, refer to the chapter “Configuring TACACS+.”

Specifying the Amount of Time for Login Input
The timeout login responsecommand allows you to specify how long the system will wait for login input
(such as username and password) before timing out. The default login value is 30 seconds; with the timeout
login response command, you can specify a timeout value from 1 to 300 seconds. To change the login timeout
value from the default of 30 seconds, use the following command in line configuration mode:
Command

Purpose

Router(config-line)#

seconds

timeout login response

Specifies how long the system will wait for login
information before timing out.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
25

Configuring Authentication
Enabling Password Protection at the Privileged Level

Enabling Password Protection at the Privileged Level
Use the aaa authentication enable default command to create a series of authentication methods that are
used to determine whether a user can access the privileged EXEC command level. You can specify up to four
authentication methods. The additional methods of authentication are used only if the previous method returns
an error, not if it fails. To specify that the authentication should succeed even if all methods return an error,
specify none as the final method in the command line.
Use the following command in global configuration mode:
Command
aaa authentication enable
default method1 [method2...]
Router(config)#

Purpose
Enables user ID and password checking for users
requesting privileged EXEC level.
Note

All aaa authentication enable default
requests sent by the router to a RADIUS
server include the username “$enab15$.”
Requests sent to a TACACS+ server will
include the username that is entered for login
authentication.

The method argument refers to the actual list of methods the authentication algorithm tries, in the sequence
entered. the table below lists the supported enable authentication methods.
Table 8: AAA Authentication Enable Default Methods

Keyword

Description

enable

Uses the enable password for authentication.

line

Uses the line password for authentication.

none

Uses no authentication.

group radius

Uses the list of all RADIUS hosts for authentication.
Note

group tacacs+

Uses the list of all TACACS+ hosts for authentication.

group group-name

Uses a subset of RADIUS or TACACS+ servers for
authentication as defined by the aaa group server
radius or aaa group server tacacs+ command.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
26

The RADIUS method does not work on a
per-username basis.

Configuring Authentication
Changing the Text Displayed at the Password Prompt

Changing the Text Displayed at the Password Prompt
Use the aaa authentication password-prompt command to change the default text that the Cisco IOS XE
software displays when prompting a user to enter a password. This command changes the password prompt
for the enable password as well as for login passwords that are not supplied by remote security servers. The
no form of this command returns the password prompt to the following default value:
Password:

The aaa authentication password-prompt command does not change any dialog that is supplied by a remote
TACACS+ or RADIUS server.
The aaa authentication password-prompt command works when RADIUS is used as the login method. You
will be able to see the password prompt defined in the command shown even when the RADIUS server is
unreachable. The aaa authentication password-prompt command does not work with TACACS+. TACACS+
supplies the NAS with the password prompt to display to the users. If the TACACS+ server is reachable, the
NAS gets the password prompt from the server and uses that prompt instead of the one defined in the aaa
authentication password-prompt command. If the TACACS+ server is not reachable, the password prompt
defined in the aaa authentication password-prompt command may be used.
Use the following command in global configuration mode:
Command

Purpose

aaa authentication
password-prompt text-string
Router(config)#

Changes the default text displayed when a user is
prompted to enter a password.

Preventing an Access Request with a Blank Username from Being Sent to the
RADIUS Server
The following configuration steps provide the ability to prevent an Access Request with a blank username
from being sent to the RADIUS server. This functionality ensures that unnecessary RADIUS server interaction
is avoided, and RADIUS logs are kept short.

Note

The aaa authentication suppress null-username command is available beginning in Cisco IOS XE
Release 2.4.

SUMMARY STEPS
1. enable
2. configure terminal
3. aaa new-model
4. aaa authentication suppress null-username

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
27

Configuring Authentication
Configuring Message Banners for AAA Authentication

DETAILED STEPS

Step 1

Command or Action

Purpose

enable

Enables privileged EXEC mode.

Example:

• Enter your password if prompted.

Router> enable

Step 2

configure terminal

Enters global configuration mode.

Example:
Router# configure terminal

Step 3

aaa new-model

Enables AAA globally.

Example:
Router(config)# configure terminal

Step 4

aaa authentication suppress null-username

Prevents an Access Request with a blank username
from being sent to the RADIUS server.

Example:
Router(config)# aaa authentication suppress
null-username

Configuring Message Banners for AAA Authentication
AAA supports the use of configurable, personalized login and failed-login banners. You can configure message
banners that will be displayed when a user logs in to the system to be authenticated using AAA and when,
for whatever reason, authentication fails.

Configuring a Login Banner
To configure a banner that is displayed when a user logs in (replacing the default message for login), perform
the following task:

Before You Begin
To create a login banner, you must configure a delimiting character that notifies the system that the following
text string must be displayed as the banner, and then the text string itself. The delimiting character is repeated
at the end of the text string to signify the end of the banner. The delimiting character can be any single character
in the extended ASCII character set, but once defined as the delimiter, that character cannot be used in the
text string for the banner.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
28

Configuring Authentication
Configuring Message Banners for AAA Authentication

SUMMARY STEPS
1. aaa new-model Device(config)# aaa new-model
2. Device(config)# aaa authentication banner delimiter string delimiter
3. Device(config)# end

DETAILED STEPS
Command or Action

Purpose

Step 1

aaa new-model Device(config)# aaa new-model

Enables AAA.

Step 2

Device(config)# aaa authentication banner delimiter string Creates a personalized login banner.
delimiter

Step 3

Device(config)# end

Returns to privileged EXEC mode.

What to Do Next
After you have configured a login banner, you must complete basic authentication configuration using AAA
if you have not already done so. For information about the different types of AAA authentication available,
please refer to “Configuring Authentication” in the Authentication, Authorization, and Accounting Configuration
Guide.

Configuring a Failed-Login Banner
To configure a message that is displayed when a user login fails (replacing the default message for failed
login), perform the following task:

Before You Begin
To create a failed-login banner, you must configure a delimiting character, which notifies the system that the
following text string must be displayed as the banner, and then configure the text string itself. The delimiting
character is repeated at the end of the text string to signify the end of the failed-login banner. The delimiting
character can be any single character in the extended ASCII character set, but once defined as the delimiter,
that character cannot be used in the text string making up the banner.

SUMMARY STEPS
1. Device(config)# aaa new-model
2. Device(config)# aaa authentication fail-message delimiter string delimiter
3. Device(config)# end

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
29

Configuring Authentication
Configuring AAA Packet of Disconnect

DETAILED STEPS
Command or Action

Purpose

Step 1

Device(config)# aaa new-model

Enables AAA.

Step 2

Device(config)# aaa authentication fail-message
delimiter string delimiter

Creates a message to be displayed when a user login
fails.

Step 3

Device(config)# end

Returns to privileged EXEC mode.

What to Do Next
After you have configured a failed-login banner, you must complete basic authentication configuration using
AAA if you have not already done so. For information about the different types of AAA authentication
available, please refer to “Configuring Authentication” in the Authentication, Authorization, and Accounting
Configuration Guide.

Configuring AAA Packet of Disconnect
Packet of disconnect (POD) terminates connections on the network access server (NAS) when particular
session attributes are identified. By using session information obtained from AAA, the POD client residing
on a UNIX workstation sends disconnect packets to the POD server running on the network access server.
The NAS terminates any inbound user session with one or more matching key attributes. It rejects requests
when required fields are missing or when an exact match is not found.
To configure POD, perform the following tasks in global configuration mode:

SUMMARY STEPS
1. Router(config)# aaa accounting network default
2. Router(config)# aaa accounting delay-start
3. Router(config)# aaa pod server server-keystring
4. Router(config)# radius-server host IP addressnon-standard

DETAILED STEPS

Step 1

Command or Action

Purpose

Router(config)# aaa accounting network default

Enables AAA accounting records.

Example:

start-stop radius

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
30

Configuring Authentication
Enabling Double Authentication

Command or Action

Purpose

Step 2

Router(config)# aaa accounting delay-start

(Optional) Delays generation of the start accounting record
until the Framed-IP-Address is assigned, allowing its use
in the POD packet.

Step 3

Router(config)# aaa pod server server-keystring

Enables POD reception.

Step 4

Router(config)# radius-server host IP
addressnon-standard

Declares a RADIUS host that uses a vendor-proprietary
version of RADIUS.

Enabling Double Authentication
Depending on the Cisco release, PPP sessions could be authenticated only by using a single authentication
method: either PAP or CHAP. Double authentication requires remote users to pass a second stage of
authentication (after CHAP or PAP authentication) before gaining network access.
This second (“double”) authentication requires a password that is known to the user but not stored on the user’s
remote host. Therefore, the second authentication is specific to a user, not to a host. This provides an additional
level of security that will be effective even if information from the remote host is stolen. In addition, this also
provides greater flexibility by allowing customized network privileges for each user.
The second stage authentication can use one-time passwords such as token card passwords, which are not
supported by CHAP. If one-time passwords are used, a stolen user password is of no use to the perpetrator.

How Double Authentication Works
With double authentication, there are two authentication/authorization stages. These two stages occur after a
remote user dials in and a PPP session is initiated.
In the first stage, the user logs in using the remote host name; CHAP (or PAP) authenticates the remote host,
and then PPP negotiates with AAA to authorize the remote host. In this process, the network access privileges
associated with the remote host are assigned to the user.

Note

We suggest that the network administrator restrict authorization at this first stage to allow only Telnet
connections to the local host.
In the second stage, the remote user must Telnet to the network access server to be authenticated. When the
remote user logs in, the user must be authenticated with AAA login authentication. The user then must enter
the access-profile command to be reauthorized using AAA. When this authorization is complete, the user has
been double authenticated, and can access the network according to per-user network privileges.
The system administrator determines what network privileges remote users will have after each stage of
authentication by configuring appropriate parameters on a security server. To use double authentication, the
user must activate it by issuing the access-profilecommand.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
31

Configuring Authentication
Enabling Double Authentication

Caution

Double authentication can cause certain undesirable events if multiple hosts share a PPP connection to a
network access server, as shown in the figure below. First, if a user, Bob, initiates a PPP session and
activates double authentication at the network access server (per the figure below), any other user will
automatically have the same network privileges as Bob until Bob’s PPP session expires. This happens
because Bob’s authorization profile is applied to the network access server’s interface during the PPP
session and any PPP traffic from other users will use the PPP session Bob established. Second, if Bob
initiates a PPP session and activates double authentication, and then--before Bob’s PPP session has
expired--another user, Jane, executes the access-profile command (or, if Jane Telnets to the network
access server and autocommand access-profileis executed), a reauthorization will occur and Jane’s
authorization profile will be applied to the interface--replacing Bob’s profile. This can disrupt or halt Bob’s
PPP traffic, or grant Bob additional authorization privileges Bob should not have.

Figure 2: Possibly Risky Topology: Multiple Hosts Share a PPP Connection to a Network Access Server

Configuring Double Authentication
To configure double authentication, you must complete the following steps:
1 Enable AAA by using the aaa-new modelglobal configuration command. For more information about
enabling AAA, refer to the chapter “AAA Overview.”
2 Use the aaa authentication command to configure your network access server to use login and PPP
authentication method lists, then apply those method lists to the appropriate lines or interfaces.
3 Use the aaa authorization command to configure AAA network authorization at login. For more
information about configuring network authorization, refer to the “Configuring Authorization” chapter.
4 Configure security protocol parameters (for example, RADIUS or TACACS+). For more information
about RADIUS, refer to the chapter “Configuring RADIUS”. For more information about TACACS+,
refer to the chapter “Configuring TACACS+.”
5 Use access control list AV pairs on the security server that the user can connect to the local host only by
establishing a Telnet connection.
6 (Optional) Configure the access-profilecommand as an autocommand. If you configure the autocommand,
remote users will not have to manually enter the access-profile command to access authorized rights
associated with their personal user profile.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
32

Configuring Authentication
Enabling Double Authentication

Note

If the access-profile command is configured as an autocommand, users will still have to Telnet to the
local host and log in to complete double authentication.
Follow these rules when creating the user-specific authorization statements (These rules relate to the default
behavior of the access-profile command):
• Use valid AV pairs when configuring access control list AV pairs on the security server.
• If you want remote users to use the interface’s existing authorization (that which existed prior to the
second stage authentication/authorization), but you want them to have different access control lists
(ACLs), you should specify only ACL AV pairs in the user-specific authorization definition. This might
be desirable if you set up a default authorization profile to apply to the remote host, but want to apply
specific ACLs to specific users.
• When these user-specific authorization statements are later applied to the interface, they can either be
added to the existing interface configuration or they can replace the existing interface
configuration--depending on which form of the access-profile command is used to authorize the user.
You should understand how the access-profile command works before configuring the authorization
statements.
• If you will be using ISDN or Multilink PPP, you must also configure virtual templates at the local host.
To troubleshoot double authentication, use the debug aaa per-user debug command. For more information
about this command, refer to the Cisco IOS Debug Command Reference .

Accessing the User Profile After Double Authentication
In double authentication, when a remote user establishes a PPP link to the local host using the local host name,
the remote host is CHAP (or PAP) authenticated. After CHAP (or PAP) authentication, PPP negotiates with
AAA to assign network access privileges associated with the remote host to the user. (We suggest that privileges
at this stage be restricted to allow the user to connect to the local host only by establishing a Telnet connection.)
When the user needs to initiate the second phase of double authentication, establishing a Telnet connection
to the local host, the user enters a personal username and password (different from the CHAP or PAP username
and password). This action causes AAA reauthentication to occur according to the personal username/password.
The initial rights associated with the local host, though, are still in place. By using the access-profile command,
the rights associated with the local host are replaced by or merged with those defined for the user in the user’s
profile.
To access the user profile after double authentication, use the following command in EXEC configuration
mode:
Command

Purpose

Router> access-profile [merge |
[ignore-sanity-checks]

replace]

Accesses the rights associated for the user after double
authentication.

If you configured the access-profile command to be executed as an autocommand, it will be executed
automatically after the remote user logs in.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
33

Configuring Authentication
Enabling Automated Double Authentication

Enabling Automated Double Authentication
You can make the double authentication process easier for users by implementing automated double
authentication. Automated double authentication provides all of the security benefits of double authentication,
but offers a simpler, more user-friendly interface for remote users. With double authentication, a second level
of user authentication is achieved when the user Telnets to the network access server or router and enters a
username and password. With automated double authentication, the user does not have to Telnet to the network
access server; instead the user responds to a dialog box that requests a username and password or personal
identification number (PIN). To use the automated double authentication feature, the remote user hosts must
be running a companion client application.

Note

Automated double authentication, like the existing double authentication feature, is for Multilink PPP
ISDN connections only. Automated double authentication cannot be used with other protocols such as
X.25 or SLIP.
Automated double authentication is an enhancement to the existing double authentication feature. To configure
automated double authentication, you must first configure double authentication by completing the following
steps:
1 Enable AAA by using the aaa-new modelglobal configuration command.
2 Use the aaa authentication command to configure your network access server to use login and PPP
authentication method lists, then apply those method lists to the appropriate lines or interfaces.
3 Use the aaa authorization command to configure AAA network authorization at login. For more
information about configuring network authorization, refer to the chapter “Configuring Authorization.”
4 Configure security protocol parameters (for example, RADIUS or TACACS+). For more information
about RADIUS, refer to the chapter “Configuring RADIUS”. For more information about TACACS+,
refer to the chapter “Configuring TACACS+.”
5 Use access control list AV pairs on the security server that the user can connect to the local host only by
establishing a Telnet connection.
6 Configure the access-profilecommand as an autocommand. If you configure the autocommand, remote
users will not have to manually enter the access-profile command to access authorized rights associated
with their personal user profile. To learn about configuring autocommands, refer to the autocommand
command in the CiscoIOS Dial Technologies Command Reference , Release 12.2.

Note

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
34

Configuring Authentication
Enabling Automated Double Authentication

be desirable if you set up a default authorization profile to apply to the remote host, but want to apply
specific ACLs to specific users.
• When these user-specific authorization statements are later applied to the interface, they can either be
added to the existing interface configuration, or replace the existing interface configuration--depending
on which form of the access-profile command is used to authorize the user. You should understand how
the access-profile command works before configuring the authorization statements.
• If you will be using ISDN or Multilink PPP, you must also configure virtual templates at the local host.
To troubleshoot double authentication, use the debug aaa per-user debug command. For more information
about this command, refer to the Cisco IOS Debug Command Reference .
After you have configured double authentication, you are ready to configure the automation enhancement.

Configuring Automated Double Authentication
To configure automated double authentication, use the following commands, starting in global configuration
mode.

SUMMARY STEPS
1. Router(config)# ip trigger-authentication
2. Do one of the following:
• Router(config)# interface bri number
•
•
• Router(config)# interface serial number :23
3. Router(config-if)# ip trigger-authentication

DETAILED STEPS

Step 1

Command or Action

Purpose

Router(config)# ip trigger-authentication

Enables automation of double authentication.

Example:
[timeout

Step 2

seconds] [port number]

Do one of the following:
• Router(config)# interface bri number

Selects an ISDN BRI or ISDN PRI interface and enter
the interface configuration mode.

•
•
• Router(config)# interface serial number :23

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
35

Configuring Authentication
Configuring the Dynamic Authorization Service for RADIUS CoA

Step 3

Command or Action

Purpose

Router(config-if)# ip trigger-authentication

Applies automated double authentication to the
interface.

Troubleshooting Automated Double Authentication
To troubleshoot automated double authentication, use the following commands in privileged EXEC mode:

SUMMARY STEPS
1. Router# show ip trigger-authentication
2. Router# clear ip trigger-authentication
3. Router# debug ip trigger-authentication

DETAILED STEPS
Command or Action

Purpose

Step 1

Router# show ip trigger-authentication

Displays the list of remote hosts for which automated double
authentication has been attempted (successfully or unsuccessfully).

Step 2

Router# clear ip trigger-authentication

Clears the list of remote hosts for which automated double authentication
has been attempted. (This clears the table displayed by the show ip
trigger-authentication command.)

Step 3

Router# debug ip trigger-authentication Displays debug output related to automated double authentication.

Configuring the Dynamic Authorization Service for RADIUS CoA
Use the following procedure to enable the router as an authentication, authorization, and accounting (AAA)
server for dynamic authorization service to support the CoA functionality that pushes the policy map in an
input and output direction.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
36

Configuring Authentication
Configuring the Dynamic Authorization Service for RADIUS CoA

SUMMARY STEPS
1. enable
2. configure terminal
3. aaa new-model
4. aaa server radius dynamic-author
5. client {ip_addr | hostname} [server-key [0 | 7] string]
6. domain {delimiter character| stripping [right-to-left]}
7. port {port-num}

DETAILED STEPS

Step 1

Command or Action

Purpose

enable

Enables privileged EXEC mode.
• Enter your password if prompted.

Example:
Router> enable

Step 2

Enters global configuration mode.

configure terminal
Example:
Router# configure terminal

Step 3

Enables AAA.

aaa new-model
Example:
Router(config)# aaa new-model

Step 4

aaa server radius dynamic-author
Example:
Router(config)# aaa server radius
dynamic-author

Step 5

client {ip_addr | hostname} [server-key [0 | 7] Configures the IP address or hostname of the AAA server client. Use
the optional server-key keyword and string argument to configure
string]
the server key at the “client” level.
Example:

Note

Router(config-locsvr-da-radius)#client
192.168.0.5 server-key cisco1

Step 6

Sets up the local AAA server for dynamic authorization service, which
must be enabled to support the CoA functionality to push the policy
map in an input and output direction and enter dynamic authorization
local server configuration mode. In this mode, the RADIUS
application commands are configured.

domain {delimiter character| stripping
[right-to-left]}

Configuring the server key at the client level overrides the
server key configured at the global level.

(Optional) Configures username domain options for the RADIUS
application.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
37

Configuring Authentication
Configuring a Device to Ignore Bounce and Disable RADIUS CoA Requests

Command or Action

• The delimiter keyword specifies the domain delimiter. One of
the following options can be specified for the character
argument: @, /, $, %, \, # or -

Example:
Router(config-locsvr-da-radius)# domain
stripping right-to-left

Example:
Router(config-locsvr-da-radius)# domain
delimiter @

Step 7

Purpose

port {port-num}

• The stripping keyword compares the incoming username with
the names oriented to the left of the @ domain delimiter.
• The right-to-left keyword terminates the string at the first
delimiter going from right to left.

Configures UDP port 3799 for CoA requests.

Example:
Router(config-locsvr-da-radius)# port
3799

Configuring a Device to Ignore Bounce and Disable RADIUS CoA Requests
When an authentication port is authenticated with multiple hosts and there is a Change of Authorization (CoA)
request for one host to flap on this port or one host session to be terminated on this port, the other hosts on
this port are also affected. Thus, an authenticated port with multiple hosts can trigger a DHCP renegotiation
from one or more hosts in the case of a flap, or it can administratively shut down the authentication port that
is hosting the session for one or more hosts.
Perform the following steps to configure the device to ignore RADIUS server Change of Authorization (CoA)
requests in the form of a bounce port command or disable port command.

SUMMARY STEPS
1. enable
2. configure terminal
3. aaa new-model
4. authentication command bounce-port ignore
5. authentication command disable-port ignore
6. end

DETAILED STEPS

Step 1

Command or Action

Purpose

enable

Enables privileged EXEC mode.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
38

Configuring Authentication
Configuring Domain Stripping at the Server Group Level

Command or Action

Purpose
• Enter your password if prompted.

Example:
Device> enable

Step 2

Enters global configuration mode.

configure terminal
Example:
Device# configure terminal

Step 3

Enables authentication, authorization, and accounting (AAA)
globally.

aaa new-model
Example:
Device(config)# aaa new-model

Step 4

authentication command bounce-port ignore
Example:

(Optional) Configures the device to ignore a RADIUS server
bounce port command that causes a host to link flap on an
authentication port, which causes DHCP renegotiation from one
or more hosts connected to this port.

Device(config)# authentication command
bounce-port ignore

Step 5

authentication command disable-port ignore
Example:
Device(config)# authentication command
disable-port ignore

Step 6

(Optional) Configures the device to ignore a RADIUS server CoA
disable port command that administratively shuts down the
authentication port that hosts one or more host sessions.
• The shutting down of the port causes session termination.
Returns to privileged EXEC mode.

end
Example:
Device(config)# end

Configuring Domain Stripping at the Server Group Level
SUMMARY STEPS
1. enable
2. configure terminal
3. aaa group server radius server-name
4. domain-stripping [strip-suffix word] [right-to-left ] [prefix-delimiter word] [delimiter word]
5. end

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
39

Configuring Authentication
Non-AAA Authentication Methods

DETAILED STEPS

Step 1

Command or Action

Purpose

enable

Enables privileged EXEC mode.

Example:

• Enter your password if prompted.

Device> enable

Step 2

configure terminal

Enters global configuration mode.

Example:
Device# configure terminal

Step 3

aaa group server radius server-name
Example:
Device(config)# aaa group server radius rad1

Step 4

domain-stripping [strip-suffix word] [right-to-left ]
[prefix-delimiter word] [delimiter word]

Adds the RADIUS server and enters server group RADIUS
configuration mode.
• The server-name argument specifies the RADIUS
server group name.
Configures domain stripping at the server group level.

Example:
Device(config-sg-radius)# domain-stripping
delimiter username@example.com

Step 5

Exits server group RADIUS configuration mode and
returns to the privileged EXEC mode.

end
Example:
Device(config-sg-radius)# end

Non-AAA Authentication Methods
Configuring Line Password Protection
You can This task is used to provide access control on a terminal line by entering the password and establishing
password checking.

Note

If you configure line password protection and then configure TACACS or extended TACACS, the TACACS
username and password take precedence over line passwords. If you have not yet implemented a security
policy, we recommend that you use AAA.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
40

Configuring Authentication
Configuring Line Password Protection

SUMMARY STEPS
1. enable
2. configure terminal
3. line [aux | console | tty | vty] line-number [ending-line-number]
4. password password
5. login

DETAILED STEPS

Step 1

Command or Action

Purpose

enable

Enables privileged EXEC mode.
• Enter your password if prompted.

Example:
Router> enable

Step 2

Enters global configuration mode.

configure terminal
Example:
Router# configure terminal

Step 3

line [aux | console | tty | vty] line-number Enters line configuration mode.
[ending-line-number]
Example:
Router(config)# line console 0

Step 4

password password

Assigns a password to a terminal or other device on a line. The password
checker is case sensitive and can include spaces; for example, the password
“Secret” is different from the password “secret,” and “two words” is an
acceptable password.

Example:
Router(config-line)# secret word

Step 5

Enables password checking at login.

Example:

You can disable line password verification by disabling password checking
by using the no version of this command.

Router(config-line)# login

Note

The login command only changes username and privilege level
but it does not execute a shell; therefore autocommands will not
be executed. To execute autocommands under this circumstance,
you need to establish a Telnet session back into the router
(loop-back). Make sure that the router has been configured for
secure Telnet sessions if you choose to implement autocommands
this way.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
41

Configuring Authentication
Establishing Username Authentication

Establishing Username Authentication
You can create a username-based authentication system, which is useful in the following situations:
• To provide a TACACS-like username and encrypted password-authentication system for networks that
cannot support TACACS
• To provide special-case logins: for example, access list verification, no password verification,
autocommand execution at login, and “no escape” situations
To establish username authentication, use the following commands in global configuration mode as needed
for your system configuration:

SUMMARY STEPS
1. Do one of the following:
• Router(config)# username name [nopassword | password password | password encryption-type
encrypted password]
•
•
• Router(config)# username name [access-class number]
2. Router(config)# username name [privilege level]
3. Router(config)# username name [autocommand command]
4. Router(config)# username name [noescape] [nohangup]

DETAILED STEPS

Step 1

Command or Action

Purpose

Do one of the following:

Establishes username authentication with encrypted
passwords.

• Router(config)# username name [nopassword |
password password | password encryption-type
encrypted password]
•
•
• Router(config)# username name [access-class number]

or
(Optional) Establishes username authentication by
access list.

Step 2

Router(config)# username name [privilege level]

Step 3

Router(config)# username name [autocommand command] (Optional) Specifies a command to be executed
automatically.

Step 4

Router(config)# username name [noescape] [nohangup]

(Optional) Sets the privilege level for the user.

(Optional) Sets a “no escape” login environment.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
42

Configuring Authentication
Enabling CHAP or PAP Authentication

What to Do Next
The keyword noescape prevents users from using escape characters on the hosts to which they are connected.
The nohangup feature does not disconnect after using the autocommand.

Caution

Passwords will be displayed in clear text in your configuration unless you enable the service
password-encryption command. For more information about the service password-encryption command,
refer to the Cisco IOS Security Command Reference.

Enabling CHAP or PAP Authentication
One of the most common transport protocols used in Internet service providers’ (ISPs’) dial solutions is the
Point-to-Point Protocol (PPP). Traditionally, remote users dial in to an access server to initiate a PPP session.
After PPP has been negotiated, remote users are connected to the ISP network and to the Internet.
Because ISPs want only customers to connect to their access servers, remote users are required to authenticate
to the access server before they can start up a PPP session. Normally, a remote user authenticates by typing
in a username and password when prompted by the access server. Although this is a workable solution, it is
difficult to administer and awkward for the remote user.
A better solution is to use the authentication protocols built into PPP. In this case, the remote user dials in to
the access server and starts up a minimal subset of PPP with the access server. This does not give the remote
user access to the ISP’s network--it merely allows the access server to talk to the remote device.
PPP currently supports two authentication protocols: Password Authentication Protocol (PAP) and Challenge
Handshake Authentication Protocol (CHAP). Both are specified in RFC 1334 and are supported on synchronous
and asynchronous interfaces. Authentication via PAP or CHAP is equivalent to typing in a username and
password when prompted by the server. CHAP is considered to be more secure because the remote user’s
password is never sent across the connection.
PPP (with or without PAP or CHAP authentication) is also supported in dialout solutions. An access server
utilizes a dialout feature when it initiates a call to a remote device and attempts to start up a transport protocol
such as PPP.
See the Cisco IOS XE Dial Technologies Configuration Guide , Release 2 for more information about CHAP
and PAP.

Note

To use CHAP or PAP, you must be running PPP encapsulation.
When CHAP is enabled on an interface and a remote device attempts to connect to it, the access server sends
a CHAP packet to the remote device. The CHAP packet requests or “challenges” the remote device to respond.
The challenge packet consists of an ID, a random number, and the host name of the local router.
When the remote device receives the challenge packet, it concatenates the ID, the remote device’s password,
and the random number, and then encrypts all of it using the remote device’s password. The remote device
sends the results back to the access server, along with the name associated with the password used in the
encryption process.
When the access server receives the response, it uses the name it received to retrieve a password stored in its
user database. The retrieved password should be the same password the remote device used in its encryption

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
43

Configuring Authentication
Enabling CHAP or PAP Authentication

process. The access server then encrypts the concatenated information with the newly retrieved password--if
the result matches the result sent in the response packet, authentication succeeds.
The benefit of using CHAP authentication is that the remote device’s password is never transmitted in clear
text. This prevents other devices from stealing it and gaining illegal access to the ISP’s network.
CHAP transactions occur only at the time a link is established. The access server does not request a password
during the rest of the call. (The local device can, however, respond to such requests from other devices during
a call.)
When PAP is enabled, the remote router attempting to connect to the access server is required to send an
authentication request. If the username and password specified in the authentication request are accepted, the
Cisco IOS XE software sends an authentication acknowledgment.
After you have enabled CHAP or PAP, the access server will require authentication from remote devices
dialing in to the access server. If the remote device does not support the enabled protocol, the call will be
dropped.
To use CHAP or PAP, you must perform the following tasks:
1 Enable PPP encapsulation.
2 Enable CHAP or PAP on the interface.
3 For CHAP, configure host name authentication and the secret or password for each remote system with
which authentication is required.

Enabling PPP Encapsulation
To enable PPP encapsulation, use the following command in interface configuration mode:
Command
Router(config-if)#

Purpose
encapsulation ppp

Enables PPP on an interface.

Enabling PAP or CHAP
To enable CHAP or PAP authentication on an interface configured for PPP encapsulation, use the following
command in interface configuration mode:
Command
Router(config-if)# ppp authentication
{protocol1 [protocol2...]} [if-needed] {default
| list-name} [callin] [one-time]

Purpose
Defines the authentication protocols supported and
the order in which they are used. In this command,
protocol1, protocol2 represent the following
protocols: CHAP, MS-CHAP, and PAP. PPP
authentication is attempted first using the first
authentication method, which is protocol1. If
protocol1 is unable to establish authentication, the
next configured protocol is used to negotiate
authentication.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
44

Configuring Authentication
Enabling CHAP or PAP Authentication

If you configure ppp authentication chap on an interface, all incoming calls on that interface that initiate a
PPP connection will have to be authenticated using CHAP; likewise, if you configure ppp authentication
pap, all incoming calls that start a PPP connection will have to be authenticated via PAP. If you configure
ppp authentication chap pap, the access server will attempt to authenticate all incoming calls that start a
PPP session with CHAP. If the remote device does not support CHAP, the access server will try to authenticate
the call using PAP. If the remote device does not support either CHAP or PAP, authentication will fail and
the call will be dropped. If you configure ppp authentication pap chap, the access server will attempt to
authenticate all incoming calls that start a PPP session with PAP. If the remote device does not support PAP,
the access server will try to authenticate the call using CHAP. If the remote device does not support either
protocol, authentication will fail and the call will be dropped. If you configure the ppp authentication
command with the callin keyword, the access server will only authenticate the remote device if the remote
device initiated the call.
Authentication method lists and the one-time keyword are only available if you have enabled AAA--they
will not be available if you are using TACACS or extended TACACS. If you specify the name of an
authentication method list with the ppp authentication command, PPP will attempt to authenticate the
connection using the methods defined in the specified method list. If AAA is enabled and no method list is
defined by name, PPP will attempt to authenticate the connection using the methods defined as the default.
The ppp authentication command with the one-time keyword enables support for one-time passwords during
authentication.
The if-needed keyword is only available if you are using TACACS or extended TACACS. The ppp
authenticationcommand with the if-needed keyword means that PPP will only authenticate the remote device
via PAP or CHAP if they have not yet authenticated during the life of the current call. If the remote device
authenticated via a standard login procedure and initiated PPP from the EXEC prompt, PPP will not authenticate
via CHAP if ppp authentication chap if-needed is configured on the interface.

Caution

If you use a list-name that has not been configured with the aaa authentication pppcommand, you disable
PPP on the line.
For information about adding a username entry for each remote system from which the local router or access
server requires authentication, see the Establishing Username Authentication, on page 42.

Inbound and Outbound Authentication
PPP supports two-way authentication. Normally, when a remote device dials in to an access server, the access
server requests that the remote device prove that it is allowed access. This is known as inbound authentication.
At the same time, the remote device can also request that the access server prove that it is who it says it is.
This is known as outbound authentication. An access server also does outbound authentication when it initiates
a call to a remote device.

Enabling Outbound PAP Authentication
To enable outbound PAP authentication, use the following command in interface configuration mode:
Command

Purpose

ppp pap sent-username
username password password

Enables outbound PAP authentication.

Router(config-if)#

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
45

Configuring Authentication
Enabling CHAP or PAP Authentication

The access server uses the username and password specified by the ppp pap sent-username command to
authenticate itself whenever it initiates a call to a remote device or when it has to respond to a remote device’s
request for outbound authentication.

Refusing PAP Authentication Requests
To refuse PAP authentication from peers requesting it, meaning that PAP authentication is disabled for all
calls, use the following command in interface configuration mode:
Command
Router(config-if)#

Purpose
Refuses PAP authentication from peers requesting
PAP authentication.

ppp pap refuse

If the refuse keyword is not used, the router will not refuse any PAP authentication challenges received from
the peer.

Creating a Common CHAP Password
For remote CHAP authentication only, you can configure your router to create a common CHAP secret
password to use in response to challenges from an unknown peer; for example, if your router calls a rotary
of routers (either from another vendor, or running an older version of the Cisco IOS software) to which a new
(that is, unknown) router has been added. The ppp chap password command allows you to replace several
username and password configuration commands with a single copy of this command on any dialer interface
or asynchronous group interface.
To enable a router calling a collection of routers to configure a common CHAP secret password, use the
following command in interface configuration mode:
Command
Router(config-if)#

Purpose
ppp chap password

secret

Enables a router calling a collection of routers to
configure a common CHAP secret password.

Refusing CHAP Authentication Requests
To refuse CHAP authentication from peers requesting it, meaning that CHAP authentication is disabled for
all calls, use the following command in interface configuration mode:
Command
Router(config-if)#

Purpose
ppp chap refuse [callin]

Refuses CHAP authentication from peers requesting
CHAP authentication.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
46

Configuring Authentication
Using MS-CHAP

If the callin keyword is used, the router will refuse to answer CHAP authentication challenges received from
the peer, but will still require the peer to answer any CHAP challenges the router sends.
If outbound PAP has been enabled (using the ppp pap sent-username command), PAP will be suggested as
the authentication method in the refusal packet.

Delaying CHAP Authentication Until Peer Authenticates
To specify that the router will not authenticate to a peer requesting CHAP authentication until after the peer
has authenticated itself to the router, use the following command in interface configuration mode:
Command

Purpose

Router(config-if)#

ppp chap wait

secret

Configures the router to delay CHAP authentication
until after the peer has authenticated itself to the
router.

This command (which is the default) specifies that the router will not authenticate to a peer requesting CHAP
authentication until the peer has authenticated itself to the router. The no ppp chap waitcommandspecifies
that the router will respond immediately to an authentication challenge.

Using MS-CHAP
Microsoft Challenge Handshake Authentication Protocol (MS-CHAP) is the Microsoft version of CHAP and
is an extension of RFC 1994. Like the standard version of CHAP, MS-CHAP is used for PPP authentication;
in this case, authentication occurs between a PC using Microsoft Windows NT or Microsoft Windows 95 and
a Cisco device or access server acting as a network access server.
MS-CHAP differs from the standard CHAP as follows:
• MS-CHAP is enabled by negotiating CHAP Algorithm 0x80 in LCP option 3, Authentication Protocol.
• The MS-CHAP Response packet is in a format designed to be compatible with Microsoft Windows NT
3.5 and 3.51, Microsoft Windows 95, and Microsoft LAN Manager 2.x. This format does not require
the authenticator to store a clear or reversibly encrypted password.
• MS-CHAP provides an authenticator-controlled authentication retry mechanism.
• MS-CHAP provides an authenticator-controlled change password mechanism.
• MS-CHAP defines a set of “reason-for failure” codes returned in the Failure packet message field.
Depending on the security protocols you have implemented, PPP authentication using MS-CHAP can be used
with or without AAA security services. If you have enabled AAA, PPP authentication using MS-CHAP can
be used in conjunction with both TACACS+ and RADIUS. The table below lists the vendor-specific RADIUS
attributes (IETF Attribute 26) that enable RADIUS to support MS-CHAP.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
47

Configuring Authentication
Using MS-CHAP

Table 9: Vendor-Specific RADIUS Attributes for MS-CHAP

Vendor-ID
Number

Vendor-Type
Number

Vendor-Proprietary
Attribute

Description

311

MSCHAP-Challenge

Contains the challenge
sent by a network access
server to an MS-CHAP
user. It can be used in
both Access-Request and
Access-Challenge
packets.

211

MSCHAP-Response

Contains the response
value provided by a PPP
MS-CHAP user in
response to the challenge.
It is only used in
Access-Request packets.
This attribute is identical
to the PPP CHAP
Identifier.

Defining PPP Authentication using MS-CHAP
To define PPP authentication using MS-CHAP, use the following commands in interface configuration mode:

SUMMARY STEPS
1. Router(config-if)# encapsulation ppp
2. Router(config-if)# ppp authentication ms-chap [if-needed] [list-name | default] [callin] [one-time]

DETAILED STEPS
Command or Action

Purpose

Step 1

Router(config-if)# encapsulation ppp

Enables PPP encapsulation.

Step 2

Router(config-if)# ppp authentication ms-chap [if-needed]
[list-name | default] [callin] [one-time]

Defines PPP authentication using MS-CHAP.

What to Do Next
If you configure ppp authentication ms-chap on an interface, all incoming calls on that interface that initiate
a PPP connection will have to be authenticated using MS-CHAP. If you configure the ppp authentication
command with the callin keyword, the access server will only authenticate the remote device if the remote
device initiated the call.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
48

Configuring Authentication
Authentication Examples

Authentication method lists and the one-time keyword are only available if you have enabled AAA--they
will not be available if you are using TACACS or extended TACACS. If you specify the name of an
authentication method list with the ppp authentication command, PPP will attempt to authenticate the
connection using the methods defined in the specified method list. If AAA is enabled and no method list is
defined by name, PPP will attempt to authenticate the connection using the methods defined as the default.
The ppp authentication command with the one-time keyword enables support for one-time passwords during
authentication.
The if-needed keyword is only available if you are using TACACS or extended TACACS. The ppp
authenticationcommand with the if-needed keyword means that PPP will only authenticate the remote device
via MS-CHAP if that device has not yet authenticated during the life of the current call. If the remote device
authenticated through a standard login procedure and initiated PPP from the EXEC prompt, PPP will not
authenticate through MS-CHAP if ppp authentication chap if-needed is configured.

Note

If PPP authentication using MS-CHAP is used with username authentication, you must include the
MS-CHAP secret in the local username/password database. For more information about username
authentication, refer to the “Establish Username Authentication” section.

Authentication Examples
RADIUS Authentication Examples
This section provides two sample configurations using RADIUS.
The following example shows how to configure the router to authenticate and authorize using RADIUS:
aaa authentication login radius-login group radius local
aaa authentication ppp radius-ppp if-needed group radius
aaa authorization exec default group radius if-authenticated
aaa authorization network default group radius
line 3
login authentication radius-login
interface serial 0
ppp authentication radius-ppp

The lines in this sample RADIUS authentication and authorization configuration are defined as follows:
• The aaa authentication login radius-login group radius local command configures the router to use
RADIUS for authentication at the login prompt. If RADIUS returns an error, the user is authenticated
using the local database.
• The aaa authentication ppp radius-ppp if-needed group radius command configures the Cisco IOS XE
software to use PPP authentication using CHAP or PAP if the user has not already logged in. If the
EXEC facility has authenticated the user, PPP authentication is not performed.
• The aaa authorization exec default group radius if-authenticated command queries the RADIUS database
for information that is used during EXEC authorization, such as autocommands and privilege levels,
but only provides authorization if the user has successfully authenticated.
• The aaa authorization network default group radius command queries RADIUS for network authorization,
address assignment, and other access lists.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
49

Configuring Authentication
TACACS Authentication Examples

• The login authentication radius-login command enables the radius-login method list for line 3.
• The ppp authentication radius-ppp command enables the radius-ppp method list for serial interface
0.
The following example shows how to configure the router to prompt for and verify a username and password,
authorize the user’s EXEC level, and specify it as the method of authorization for privilege level 2. In this
example, if a local username is entered at the username prompt, that username is used for authentication.
If the user is authenticated using the local database, EXEC authorization using RADIUS will fail because no
data is saved from the RADIUS authentication. The method list also uses the local database to find an
autocommand. If there is no autocommand, the user becomes the EXEC user. If the user then attempts to
issue commands that are set at privilege level 2, TACACS+ is used to attempt to authorize the command.
aaa authentication login default group radius local
aaa authorization exec default group radius local
aaa authorization command 2 default group tacacs+ if-authenticated
radius-server host 172.16.71.146 auth-port 1645 acct-port 1646
radius-server attribute 44 include-in-access-req
radius-server attribute 8 include-in-access-req

The lines in this sample RADIUS authentication and authorization configuration are defined as follows:
• The aaa authentication login default group radius local command specifies that the username and password
are verified by RADIUS or, if RADIUS is not responding, by the router’s local user database.
• The aaa authorization exec default group radius local command specifies that RADIUS authentication
information be used to set the user’s EXEC level if the user authenticates with RADIUS. If no RADIUS
information is used, this command specifies that the local user database be used for EXEC authorization.
• The aaa authorization command 2 default group tacacs+ if-authenticated command specifies TACACS+
authorization for commands set at privilege level 2, if the user has already successfully authenticated.
• The radius-server host 172.16.71.146 auth-port 1645 acct-port 1646 command specifies the IP address
of the RADIUS server host, the UDP destination port for authentication requests, and the UDP destination
port for accounting requests.
• The radius-server attribute 44 include-in-access-req command sends RADIUS attribute 44
(Acct-Session-ID) in access-request packets.
• The radius-server attribute 8 include-in-access-req command sends RADIUS attribute 8
(Framed-IP-Address) in access-request packets.

TACACS Authentication Examples
The following example shows how to configure TACACS+ as the security protocol to be used for PPP
authentication:
aaa new-model
aaa authentication ppp test group tacacs+ local
interface serial 0
ppp authentication chap pap test
tacacs-server host 192.0.2.3
tacacs-server key goaway

The lines in this sample TACACS+ authentication configuration are defined as follows:
• The aaa new-model command enables the AAA security services.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
50

Configuring Authentication
Kerberos Authentication Examples

• The aaa authentication command defines a method list, “test,” to be used on serial interfaces running
PPP. The keywords group tacacs+ means that authentication will be done through TACACS+. If
TACACS+ returns an ERROR of some sort during authentication, the keyword local indicates that
authentication will be attempted using the local database on the network access server.
• The interface command selects the line.
• The ppp authentication command applies the test method list to this line.
• The tacacs-server host command identifies the TACACS+ daemon as having an IP address of 192.0.2.3.
• The tacacs-server key command defines the shared encryption key to be “goaway.”
The following example shows how to configure AAA authentication for PPP:
aaa authentication ppp default if-needed group tacacs+ local

In this example, the keyword default means that PPP authentication is applied by default to all interfaces.
The if-needed keyword means that if the user has already authenticated by going through the ASCII login
procedure, then PPP is not necessary and can be skipped. If authentication is needed, the keywords group
tacacs+ means that authentication will be done through TACACS+. If TACACS+ returns an ERROR of some
sort during authentication, the keyword local indicates that authentication will be attempted using the local
database on the network access server.
The following example shows how to create the same authentication algorithm for PAP, but it calls the method
list “MIS-access” instead of “default”:
aaa authentication ppp MIS-access if-needed group tacacs+ local
interface serial 0
ppp authentication pap MIS-access

In this example, because the list does not apply to any interfaces (unlike the default list, which applies
automatically to all interfaces), the administrator must select interfaces to which this authentication scheme
should apply by using the interface command. The administrator must then apply this method list to those
interfaces by using the ppp authentication command.

Kerberos Authentication Examples
To specify Kerberos as the login authentication method, use the following command:
aaa authentication login default krb5

To specify Kerberos authentication for PPP, use the following command:
aaa authentication ppp default krb5

AAA Scalability Example
The following example shows a general security configuration using AAA with RADIUS as the security
protocol. In this example, the network access server is configured to allocate 16 background processes to
handle AAA requests for PPP.
aaa new-model
radius-server
radius-server
radius-server
username root

host alcatraz
key myRaDiUSpassWoRd
configure-nas
password ALongPassword

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
51

Configuring Authentication
AAA Scalability Example

aaa authentication ppp dialins group radius local
aaa authentication login admins local
aaa authorization network default group radius local
aaa accounting network default start-stop group radius
aaa processes 16
line 1 16
autoselect ppp
autoselect during-login
login authentication admins
modem dialin
interface group-async 1
group-range 1 16
encapsulation ppp
ppp authentication pap dialins

The lines in this sample RADIUS AAA configuration are defined as follows:
• The aaa new-model command enables AAA network security services.
• The radius-server host command defines the name of the RADIUS server host.
• The radius-server key command defines the shared secret text string between the network access server
and the RADIUS server host.
• The radius-server configure-nas command defines that the Cisco router or access server will query
the RADIUS server for static routes and IP pool definitions when the device first starts up.
• The username command defines the username and password to be used for the PPP Password
Authentication Protocol (PAP) caller identification.
• The aaa authentication ppp dialins group radius local command defines the authentication method
list “dialins,” which specifies that RADIUS authentication, then (if the RADIUS server does not respond)
local authentication will be used on serial lines using PPP.
• The aaa authentication login admins local command defines another method list, “admins,” for login
authentication.
• The aaa authorization network default group radius local command is used to assign an address and
other network parameters to the RADIUS user.
• The aaa accounting network default start-stop group radius command tracks PPP usage.
• The aaa processes command allocates 16 background processes to handle AAA requests for PPP.
• The line command switches the configuration mode from global configuration to line configuration and
identifies the specific lines being configured.
• The autoselect ppp command allows a PPP session to start up automatically on these selected lines.
• The autoselect during-login command is used to display the username and password prompt without
pressing the Return key. After the user logs in, the autoselect function (in this case, PPP) begins.
• The login authentication admins command applies the “admins” method list for login authentication.
• The modem dialin command configures modems attached to the selected lines to only accept incoming
calls.
• The interface group-async command selects and defines an asynchronous interface group.
• The group-range command defines the member asynchronous interfaces in the interface group.
• The encapsulation ppp command sets PPP as the encapsulation method used on the specified interfaces.
• The ppp authentication pap dialinscommand applies the “dialins” method list to the specified interfaces.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
52

Configuring Authentication
Example: Configuring Login and Failed-Login Banners for AAA Authentication

Example: Configuring Login and Failed-Login Banners for AAA Authentication
The following example shows how to configure a login banner that is displayed when a user logs in to the
system, (in this case, the phrase “Unauthorized Access Prohibited”). The asterisk (*) is used as the delimiting
character. RADIUS is specified as the default login authentication method.
Device> enable
Device# configure terminal
Device(config)# aaa new-model
Device(config)# aaa authentication banner *Unauthorized Access Prohibited*
Device(config)# aaa authentication login default group radius

This configuration displays the following login banner:
Unauthorized Access Prohibited
Username:

The following example shows how to configure a failed-login banner that is displayed when a user tries to
log in to the system and fails, (in this case, the phrase “Failed login. Try again”). The asterisk (*) is used as
the delimiting character. RADIUS is specified as the default login authentication method.
Device> enable
Device# configure terminal
Device(config)# aaa new-model
Device(config)# aaa authentication banner *Unauthorized Access Prohibited*
Device(config)# aaa authentication fail-message *Failed login. Try again.*
Device(config)# aaa authentication login default group radius

This configuration displays the following login and failed-login banner:
Unauthorized Access Prohibited
Username:
Password:
Failed login. Try again.

AAA Packet of Disconnect Server Key Example
The following example shows how to configure POD (packet of disconnect), which terminates connections
on the network access server (NAS) when particular session attributes are identified.
aaa new-model
aaa authentication ppp default radius
aaa accounting network default start-stop radius
aaa accounting delay-start
aaa pod server server-key xyz123
radius-server host 192.0.2.3 non-standard
radius-server key rad123

Double Authentication Examples
The examples in this section illustrate possible configurations to be used with double authentication. Your
configurations could differ significantly, depending on your network and security requirements.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
53

Configuring Authentication
Double Authentication Examples

Note

These configuration examples include specific IP addresses and other specific information. This information
is for illustration purposes only: your configuration will use different IP addresses, different usernames
and passwords, and different authorization statements.

Configuration of the Local Host for AAA with Double Authentication Examples
These two examples show how to configure a local host to use AAA for PPP and login authentication, and
for network and EXEC authorization. An example each is shown for RADIUS and for TACACS+.
In both the examples, the first three lines configure AAA with a specific server as the AAA server. The next
two lines configure AAA for PPP and login authentication, and the last two lines configure network and EXEC
authorization. The last line is necessary only if the access-profile command will be executed as an
autocommand.
The following example shows device configuration with a RADIUS AAA server:
aaa new-model
radius-server host secureserver
radius-server key myradiuskey
aaa authentication ppp default group radius
aaa authentication login default group radius
aaa authorization network default group radius
aaa authorization exec default group radius

The following example shows device configuration with a TACACS+ server:
aaa new-model
tacacs-server host security
tacacs-server key mytacacskey
aaa authentication ppp default group tacacs+
aaa authentication login default group tacacs+
aaa authorization network default group tacacs+
aaa authorization exec default group tacacs+

Configuration of the AAA Server for First-Stage PPP Authentication and Authorization Example
This example shows a configuration on the AAA server. A partial sample AAA configuration is shown for
RADIUS.
TACACS+ servers can be configured similarly. (See the Complete Configuration with TACACS Example.)
This example defines authentication/authorization for a remote host named “hostx” that will be authenticated
by CHAP in the first stage of double authentication. Note that the ACL AV pair limits the remote host to
Telnet connections to the local host. The local host has the IP address 10.0.0.2.
The following example shows a partial AAA server configuration for RADIUS:
hostx

Password = “welcome”
User-Service-Type = Framed-User,
Framed-Protocol = PPP,
cisco-avpair = “lcp:interface-config=ip unnumbered fastethernet 0”,
cisco-avpair = “ip:inacl#3=permit tcp any 172.21.114.0 0.0.0.255 eq telnet”,
cisco-avpair = “ip:inacl#4=deny icmp any any”,
cisco-avpair = “ip:route#5=10.0.0.0 255.0.0.0”,
cisco-avpair = “ip:route#6=10.10.0.0 255.0.0.0”,
cisco-avpair = “ipx:inacl#3=deny any”

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
54

Configuring Authentication
Double Authentication Examples

Configuration of the AAA Server for Second-Stage Per-User Authentication and Authorization
Examples
This section contains partial sample AAA configurations on a RADIUS server. These configurations define
authentication and authorization for a user (Pat) with the username “patuser,” who will be user-authenticated
in the second stage of double authentication.
TACACS+ servers can be configured similarly. (See the Complete Configuration with TACACS Example.)
Three examples show sample RADIUS AAA configurations that could be used with each of the three forms
of the access-profile command.
The first example shows a partial sample AAA configuration that works with the default form (no keywords)
of the access-profile command. Note that only ACL AV pairs are defined. This example also sets up the
access-profile command as an autocommand.
patuser

Password = “welcome”
User-Service-Type = Shell-User,
cisco-avpair = “shell:autocmd=access-profile”
User-Service-Type = Framed-User,
Framed-Protocol = PPP,
cisco-avpair = “ip:inacl#3=permit tcp any host 10.0.0.2 eq telnet”,
cisco-avpair = “ip:inacl#4=deny icmp any any”

The second example shows a partial sample AAA configuration that works with the access-profile merge
form of the access-profile command. This example also sets up the access-profile mergecommand as an
autocommand.
patuser

Password = “welcome”
User-Service-Type = Shell-User,
cisco-avpair = “shell:autocmd=access-profile merge”
User-Service-Type = Framed-User,
Framed-Protocol = PPP,
cisco-avpair = “ip:inacl#3=permit tcp any any”
cisco-avpair = “ip:route=10.0.0.0 255.255.0.0",
cisco-avpair = “ip:route=10.1.0.0 255.255.0.0",
cisco-avpair = “ip:route=10.2.0.0 255.255.0.0"

The third example shows a partial sample AAA configuration that works with the access-profile replace
form of the access-profile command. This example also sets up the access-profile replacecommand as an
autocommand.
patuser

Password = “welcome”
User-Service-Type = Shell-User,
cisco-avpair = “shell:autocmd=access-profile replace”
User-Service-Type = Framed-User,
Framed-Protocol = PPP,
cisco-avpair = “ip:inacl#3=permit tcp any any”,
cisco-avpair = “ip:inacl#4=permit icmp any any”,
cisco-avpair = “ip:route=10.10.0.0 255.255.0.0",
cisco-avpair = “ip:route=10.11.0.0 255.255.0.0",
cisco-avpair = “ip:route=10.12.0.0 255.255.0.0"

Complete Configuration with TACACS Example
This example shows TACACS+ authorization profile configurations both for the remote host (used in the first
stage of double authentication) and for specific users (used in the second stage of double authentication). This
TACACS+ example contains approximately the same configuration information as shown in the previous
RADIUS examples.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
55

Configuring Authentication
Double Authentication Examples

This sample configuration shows authentication/authorization profiles on the TACACS+ server for the remote
host “hostx” and for three users, with the usernames “pat_default,” “pat_merge,” and “pat_replace.” The
configurations for these three usernames illustrate different configurations that correspond to the three different
forms of the access-profile command. The three user configurations also illustrate setting up the autocommand
for each form of the access-profile command.
The figure below shows the topology. The example that follows the figure shows a TACACS+ configuration
file.
Figure 3: Example Topology for Double Authentication

This sample configuration shows authentication/authorization profiles on the TACACS+ server for the remote
host “hostx” and for three users, with the usernames “pat_default,” “pat_merge,” and “pat_replace.”
key = “mytacacskey”
default authorization = permit
#-----------------------------Remote Host (BRI)------------------------#
# This allows the remote host to be authenticated by the local host
# during fist-stage authentication, and provides the remote host
# authorization profile.
#
#----------------------------------------------------------------------user = hostx
{
login = cleartext “welcome”
chap = cleartext “welcome”
service = ppp protocol = lcp {
interface-config=”ip unnumbered fastethernet 0"
}
service = ppp protocol = ip {
# It is important to have the hash sign and some string after
# it. This indicates to the NAS that you have a per-user
# config.
inacl#3=”permit tcp any 172.21.114.0 0.0.0.255 eq telnet”
inacl#4=”deny icmp any any”
route#5=”10.0.0.0 255.0.0.0"
route#6=”10.10.0.0 255.0.0.0"
}
service = ppp protocol = ipx {
# see previous comment about the hash sign and string, in protocol = ip
inacl#3=”deny any”
}
}
#------------------- “access-profile” default user “only acls” -----------------#
# Without arguments, access-profile removes any access-lists it can find
# in the old configuration (both per-user and per-interface), and makes sure
# that the new profile contains ONLY access-list definitions.
#
#-------------------------------------------------------------------------------user = pat_default

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
56

Configuring Authentication
Double Authentication Examples

{
login = cleartext “welcome”
chap = cleartext “welcome”
service = exec
{
# This is the autocommand that executes when pat_default logs in.
autocmd = “access-profile”
}
service = ppp protocol = ip {
# Put whatever access-lists, static routes, whatever
# here.
# If you leave this blank, the user will have NO IP
# access-lists (not even the ones installed prior to
# this)!
inacl#3=”permit tcp any host 10.0.0.2 eq telnet”
inacl#4=”deny icmp any any”
}
service = ppp protocol = ipx {
# Put whatever access-lists, static routes, whatever
# here.
# If you leave this blank, the user will have NO IPX
# access-lists (not even the ones installed prior to
# this)!
}
}
#--------------------- “access-profile merge” user --------------------------#
# With the 'merge' option, first all old access-lists are removed (as before),
# but then (almost) all AV pairs are uploaded and installed. This will allow
# for uploading any custom static routes, sap-filters, and so on, that the user
# may need in his or her profile. This needs to be used with care, as it leaves
# open the possibility of conflicting configurations.
#
#----------------------------------------------------------------------------user = pat_merge
{
login = cleartext “welcome”
chap = cleartext “welcome”
service = exec
{
# This is the autocommand that executes when pat_merge logs in.
autocmd = “access-profile merge”
}
service = ppp protocol = ip
{
# Put whatever access-lists, static routes, whatever
# here.
# If you leave this blank, the user will have NO IP
# access-lists (not even the ones installed prior to
# this)!
inacl#3=”permit tcp any any”
route#2=”10.0.0.0 255.255.0.0"
route#3=”10.1.0.0 255.255.0.0"
route#4=”10.2.0.0 255.255.0.0"
}
service = ppp protocol = ipx
{
# Put whatever access-lists, static routes, whatever
# here.
# If you leave this blank, the user will have NO IPX
# access-lists (not even the ones installed prior to
# this)!
}
}
#--------------------- “access-profile replace” user ---------------------------#
# With the 'replace' option, ALL old configuration is removed and ALL new
# configuration is installed.
#
# One caveat: access-profile checks the new configuration for address-pool and
# address AV pairs. As addresses cannot be renegotiated at this point, the

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
57

Configuring Authentication
Automated Double Authentication Example

# command will fail (and complain) when it encounters such an AV pair.
# Such AV pairs are considered to be “invalid” for this context.
#------------------------------------------------------------------------------user = pat_replace
{
login = cleartex
t
“
welcome
”
chap = cleartext “welcome”
service = exec
{
# This is the autocommand that executes when pat_replace logs in.
autocmd = “access-profile replace”
}
service = ppp protocol = ip
{
# Put whatever access-lists, static routes, whatever
# here.
# If you leave this blank, the user will have NO IP
# access-lists (not even the ones installed prior to
# this)!
inacl#3=”permit tcp any any”
inacl#4=”permit icmp any any”
route#2=”10.10.0.0 255.255.0.0"
route#3=”10.11.0.0 255.255.0.0"
route#4=”10.12.0.0 255.255.0.0"
}
service = ppp protocol = ipx
{
# put whatever access-lists, static routes, whatever
# here.
# If you leave this blank, the user will have NO IPX
# access-lists (not even the ones installed prior to
# this)!
}
}

Automated Double Authentication Example
This example shows a complete configuration file with automated double authentication configured. The
configuration commands that apply to automated double authentication are preceded by descriptions with a
double asterisk (**).
Current configuration:
!
version 11.3
no service password-encryption
!
hostname myrouter
!
!
! **The following AAA commands are used to configure double authentication:
!
! **The following command enables AAA:
aaa new-model
! **The following command enables user authentication via the RADIUS AAA server:
!
aaa authentication login default none
aaa authentication ppp default group radius
! **The following command causes the remote user’s authorization profile to be
! downloaded from the AAA server to the router when required:
!
aaa authorization network default group radius
!
enable password mypassword

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
58

Configuring Authentication
Automated Double Authentication Example

!
ip host blue 172.21.127.226
ip host green 172.21.127.218
ip host red 172.21.127.114
ip domain-name example.com
ip name-server 172.16.2.75
!
!
interface FastEthernet0/0/0
ip address 172.21.127.186 255.255.255.248
no ip route-cache
no ip mroute-cache
no keepalive
ntp disable
no cdp enable
!
interface Virtual-Template1
ip unnumbered loopback0
no ip route-cache
no ip mroute-cache
!
! **The following command specifies that device authentication occurs via PPP CHAP:
ppp authentication chap
!
router eigrp 109
network 172.21.0.0
no auto-summary
!
ip default-gateway 172.21.127.185
no ip classless
ip route 172.21.127.114 255.255.255.255 172.21.127.113
! **Virtual profiles are required for double authentication to work:
virtual-profile virtual-template 1
dialer-list 1 protocol ip permit
no cdp run
! **The following command defines where the TACACS+ AAA server is:
tacacs-server host 172.16.57.35 port 1049
tacacs-server timeout 90
! **The following command defines the key to use with TACACS+ traffic (required):
tacacs-server key mytacacskey
snmp-server community public RO
!
line con 0
exec-timeout 0 0
login authentication console
line aux 0
transport input all
line vty 0 4
exec-timeout 0 0
password lab
!
end

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
59

Configuring Authentication
Additional References

• The username command defines the username and password to be used for the PPP Password
Authentication Protocol (PAP) caller identification.
• The radius-server host command defines the name of the RADIUS server host.
• The radius-server key command defines the shared secret text string between the network access server
and the RADIUS server host.
• The interface group-async command selects and defines an asynchronous interface group.
• The group-range command defines the member asynchronous interfaces in the interface group.
• The encapsulation ppp command sets PPP as the encapsulation method used on the specified interfaces.
• The ppp authentication ms-chap dialinscommand selects MS-CHAP as the method of PPP
authentication and applies the “dialins” method list to the specified interfaces.
• The line command switches the configuration mode from global configuration to line configuration and
identifies the specific lines being configured.
• The autoselect ppp command allows a PPP session to start up automatically on these selected lines.
• The autoselect during-login command is used to display the username and password prompt without
pressing the Return key. After the user logs in, the autoselect function (in this case, PPP) begins.
• The login authentication admins command applies the “admins” method list for login authentication.
• The modem dialin command configures modems attached to the selected lines to only accept incoming
calls.

Additional References
The following sections provide references related to the Configuring Authentication feature.
Related Documents
Related Topic

Document Title

Authorization

Configuring Authorization in the Cisco IOS XE
Security Configuration Guide: Securing User
Services, Release 2.

Accounting

Configuring Accounting in the Cisco IOS XE Security
Configuration Guide: Securing User Service , Release
2.

Security commands

Cisco IOS Security Command Reference

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
60

Configuring Authentication
Additional References

Standards
Standard

Title

No new or modified standards are supported by this -feature, and support for existing standards has not
been modified by this feature.

MIBs
MIB

MIBs Link

No new or modified MIBs are supported by this
feature, and support for existing MIBs has not been
modified by this feature.

To locate and download MIBs for selected platforms,
Cisco IOS XE software releases, and feature sets, use
Cisco MIB Locator found at the following URL:
http://www.cisco.com/go/mibs

RFCs
RFC

Title

RFC 1334

PPP Authentication Protocols

RFC 2433

Microsoft PPP CHAP Extensions

RFC 2903

Generic AAA Architecture

RFC 2904

AAA Authorization Framework

RFC 2906

AAA Authorization Requirements

RFC 2989

Criteria for Evaluating AAA Protocols for Network
Access

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
61

Configuring Authentication
Feature Information for Configuring Authentication

Technical Assistance
Description

Link

The Cisco Support website provides extensive online http://www.cisco.com/techsupport
resources, including documentation and tools for
troubleshooting and resolving technical issues with
Cisco products and technologies.
To receive security and technical information about
your products, you can subscribe to various services,
such as the Product Alert Tool (accessed from Field
Notices), the Cisco Technical Services Newsletter,
and Really Simple Syndication (RSS) Feeds.
Access to most tools on the Cisco Support website
requires a Cisco.com user ID and password.

Feature Information for Configuring Authentication
The following table provides release information about the feature or features described in this module. This
table lists only the software release that introduced support for a given feature in a given software release
train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support.
To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Table 10: Feature Information for Configuring Authentication

Feature Name

Releases

AAA Method Lists Enhancement Cisco IOS XE Release 2.1

Feature Information
This feature allows you to enable
fallback methods for
authentication, authorization or
accounting. The fallback methods
could include trying groups of
RADIUS or TACACS+ servers or
a local database in some cases.
In Cisco IOS XE Release 2.1, this
feature was introduced on the Cisco
ASR 1000 Series Aggregation
Services Routers.
The following command was
introduced or modified: aaa
authentication ppp.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
62

Configuring Authentication
Feature Information for Configuring Authentication

Feature Name

Releases

Feature Information

AAA Per-User Scalability

Cisco IOS XE Release 2.3

The AAA Per-User Scalability
feature supports two RADIUS
VSAs for ip vrf and ip
unnumbered commands and
creates subvirtual access interfaces
if specified instead of full VA
interface to achieve higher
scalability.
In Cisco IOS XE Release 2.3, this
feature was introduced on the Cisco
ASR 1000 Series Aggregation
Services Routers.

Challege Handshake
Authentication Protocol (CHAP)

Cisco IOS XE Release 2.1

PPP currently supports two
authentication protocols: Password
Authentication Protocol (PAP) and
Challenge Handshake
Authentication Protocol (CHAP).
Both are specified in RFC 1334
and are supported on synchronous
and asynchronous interfaces.
Authentication via PAP or CHAP
is equivalent to typing in a
username and password when
prompted by the server. CHAP is
considered to be more secure
because the remote user’s password
is never sent across the connection.
In Cisco IOS XE Release 2.1, this
feature was introduced on the Cisco
ASR 1000 Series Aggregation
Services Routers.
The following commands were
introduced or modified: ppp
authentication, ppp chap
password, ppp chap refuse.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
63

Configuring Authentication
Feature Information for Configuring Authentication

Feature Name

Releases

Feature Information

Domain Stripping at the Server
Group Level

Cisco IOS XE Release 3.4S

The Domain Stripping feature
allows domain stripping to be
configured at the server group
level. Per-server group
configuration overrides the global
configuration.
The following sections provide
information about this feature:
• Domain Stripping
• Configuring Domain
Stripping at the Server Group
Level
The following command was
introduced: domain-stripping.

Double Authentication

Cisco IOS XE Release 2.1

In Cisco IOS XE Release 2.1, this
feature was introduced on the Cisco
ASR 1000 Series Aggregation
Services Routers.
The following commands were
introduced or modified: aaa
authentication, aaa
authorization, access-profile.

Message Banners for AAA
Authentication

Cisco IOS XE Release 2.1

In Cisco IOS XE Release 2.1, this
feature was introduced on the Cisco
ASR 1000 Series Aggregation
Services Routers.
The following command was
introduced: aaa authentication
banner.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
64

Configuring Authentication
Feature Information for Configuring Authentication

Feature Name

Releases

Feature Information

MS-CHAP Version 1

Cisco IOS XE Release 2.1

Microsoft Challenge Handshake
Authentication Protocol
(MS-CHAP) is the Microsoft
version of CHAP and is an
extension of RFC 1994. Like the
standard version of CHAP,
MS-CHAP is used for PPP
authentication; in this case,
authentication occurs between a PC
using Microsoft Windows NT or
Microsoft Windows 95 and a Cisco
router or access server acting as a
network access server.
In Cisco IOS XE Release 2.1, this
feature was introduced on the Cisco
ASR 1000 Series Aggregation
Services Routers.
The following commands were
introduced or modified: ppp
authentication.

Password Authentication Protocol Cisco IOS XE Release 2.1
(PAP)

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
65

Configuring Authentication
Feature Information for Configuring Authentication

Feature Name

Releases

RADIUS—CLI to Prevent Sending Cisco IOS XE Release 2.4
of Access Request with a Blank
Username

Feature Information
This authentication feature prevents
an Access Request with a blank
username from being sent to the
RADIUS server. This functionality
ensures that unnecessary RADIUS
server interaction is avoided, and
RADIUS logs are kept short.
In Cisco IOS XE Release 2.4, this
feature was introduced on the Cisco
ASR 1000 Series Aggregation
Services Routers.
The following command was
introduced: aaa authentication
suppress null-username.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
66

CHAPTER

RADIUS Change of Authorization
The RADIUS Change of Authorization (CoA) feature provides a mechanism to change the attributes of an
authentication, authorization, and accounting (AAA) session after it is authenticated. When a policy changes
for a user or user group in AAA, administrators can send the RADIUS CoA packets from the AAA server
such as a Cisco Secure Access Control Server (ACS) to reinitialize authentication and apply the new policy.
• Finding Feature Information, page 67
• Information About RADIUS Change of Authorization, page 67
• How to Configure RADIUS Change of Authorization, page 72
• Configuration Examples for RADIUS Change of Authorization, page 77
• Additional References for RADIUS Change of Authorization, page 78
• Feature Information for RADIUS Change of Authorization, page 79

Information About RADIUS Change of Authorization
About RADIUS Change of Authorization
A standard RADIUS interface is typically used in a pulled model, in which the request originates from a
device attached to a network and the response is sent from the queried servers. The Cisco software supports
the RADIUS CoA request defined in RFC 5176 that is used in a pushed model, in which the request originates

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
67

RADIUS Change of Authorization
About RADIUS Change of Authorization

from the external server to the device attached to the network, and enables the dynamic reconfiguring of
sessions from external authentication, authorization, and accounting (AAA) or policy servers.
Use the following per-session CoA requests:
• Session reauthentication
• Session termination
• Session termination with port shutdown
• Session termination with port bounce
• Security and Password
• Accounting

Attribute Number

Attribute Name

State

Calling-Station-ID

Acct-Session-ID

Message-Authenticator

101

Error-Cause

The following table shows the possible values for the Error-Cause attribute.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
68

RADIUS Change of Authorization
About RADIUS Change of Authorization

Table 12: Error-Cause Values

Value

Explanation

201

Residual Session Context Removed

202

Invalid EAP Packet (Ignored)

401

Unsupported Attribute

402

Missing Attribute

403

NAS Identification Mismatch

404

Invalid Request

405

Unsupported Service

406

Unsupported Extension

407

Invalid Attribute Value

501

Administratively Prohibited

502

Request Not Routable (Proxy)

503

Session Context Not Found

504

Session Context Not Removable

505

Other Proxy Processing Error

506

Resources Unavailable

507

Request Initiated

508

Multiple Session Selection Unsupported

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
69

RADIUS Change of Authorization
About RADIUS Change of Authorization

Note

CoA ACK Response Code
If an authorization state is changed successfully, a positive acknowledgment (ACK) is sent. The attributes
returned within a CoA ACK can vary based on the CoA Request.

CoA NAK Response Code
A negative acknowledgment (NAK) indicates a failure to change the authorization state and can include
attributes that indicate the reason for the failure.

Command

Cisco VSA

Bounce host port

Cisco:Avpair=“subscriber:command=bounce-host-port”

Disable host port

Cisco:Avpair=“subscriber:command=disable-host-port”

Reauthenticate host

Cisco:Avpair=“subscriber:command=reauthenticate”

Terminate session

This is a standard disconnect request that does not require a VSA

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
70

RADIUS Change of Authorization
About RADIUS Change of Authorization

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
71

RADIUS Change of Authorization
How to Configure RADIUS Change of Authorization

How to Configure RADIUS Change of Authorization
Configuring RADIUS Change of Authorization
SUMMARY STEPS
1. enable
2. configure terminal
3. aaa new-model
4. aaa server radius dynamic-author
5. client {ip-address | name [vrf vrf-name]} server-key [0 | 7] string
6. port port-number
7. auth-type {any | all | session-key}
8. ignore session-key
9. ignore server-key
10. exit

DETAILED STEPS

Step 1

Command or Action

Purpose

enable

Enables privileged EXEC mode.

Example:

• Enter your password if prompted.

Device> enable

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
72

RADIUS Change of Authorization
Configuring RADIUS Change of Authorization

Step 2

Command or Action

Purpose

configure terminal

Enters global configuration mode.

Example:
Device# configure terminal

Step 3

Enables authentication, authorization, and accounting (AAA)
globally.

aaa new-model
Example:
Device(config)# aaa new-model

Step 4

aaa server radius dynamic-author
Example:
Device(config)# aaa server radius
dynamic-author

Step 5

client {ip-address | name [vrf vrf-name]}
server-key [0 | 7] string

Enters dynamic authorization local server configuration mode
and specifies a RADIUS client from which a device accepts
Change of Authorization (CoA) and disconnect requests.
Configures the device as a AAA server to facilitate interaction
with an external policy server.
Configures the RADIUS key to be shared between a device and
RADIUS clients.

Example:
Device(config-locsvr-da-radius)# client
10.0.0.1

Step 6

port port-number

Specifies the port on which a device listens for RADIUS requests
from configured RADIUS clients.

Example:

Note

Device(config-locsvr-da-radius)# port 3799

Step 7

auth-type {any | all | session-key}
Example:

The default port for packet of disconnect is 1700. Port
3799 is required to interoperate with ACS 5.1.

Specifies the type of authorization that the device must use for
RADIUS clients. The client must match the configured attributes
for authorization.

Device(config-locsvr-da-radius)# auth-type
all

Step 8

(Optional) Configures the device to ignore the session key.

ignore session-key
Example:
Device(config-locsvr-da-radius)# ignore
session-key

Step 9

(Optional) Configures the device to ignore the server key.

ignore server-key
Example:
Device(config-locsvr-da-radius)# ignore
server-key

Step 10

Returns to global configuration mode.

exit
Example:
Device(config-locsvr-da-radius)# exit

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
73

RADIUS Change of Authorization
Configuring a Device to Ignore Bounce and Disable RADIUS CoA Requests

SUMMARY STEPS
1. enable
2. configure terminal
3. aaa new-model
4. authentication command bounce-port ignore
5. authentication command disable-port ignore
6. end

DETAILED STEPS

Step 1

Command or Action

Purpose

enable

Enables privileged EXEC mode.

Example:

• Enter your password if prompted.

Device> enable

Step 2

configure terminal

Enters global configuration mode.

Example:
Device# configure terminal

Step 3

aaa new-model

Enables authentication, authorization, and accounting (AAA)
globally.

Example:
Device(config)# aaa new-model

Step 4

authentication command bounce-port ignore
Example:

Device(config)# authentication command
bounce-port ignore

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
74

RADIUS Change of Authorization
Configuring the Dynamic Authorization Service for RADIUS CoA

Step 5

Command or Action

Purpose

authentication command disable-port ignore

(Optional) Configures the device to ignore a RADIUS server CoA
disable port command that administratively shuts down the
authentication port that hosts one or more host sessions.

Example:

• The shutting down of the port causes session termination.

Device(config)# authentication command
disable-port ignore

Step 6

Returns to privileged EXEC mode.

end
Example:
Device(config)# end

Configuring the Dynamic Authorization Service for RADIUS CoA
Perform the following steps to enable the device as an authentication, authorization, and accounting (AAA)
server for the dynamic authorization service. This service supports the Change of Authorization (CoA)
functionality that pushes the policy map in an input and output direction.

SUMMARY STEPS
1. enable
2. configure terminal
3. aaa new-model
4. aaa server radius dynamic-author
5. client {ip-addr | hostname} [server-key [0 | 7] string]
6. domain {delimiter character | stripping | [right-to-left]}
7. port port-num
8. end

DETAILED STEPS

Step 1

Command or Action

Purpose

enable

Enables privileged EXEC mode.
• Enter your password if prompted.

Example:
Device> enable

Step 2

Enters global configuration mode.

configure terminal
Example:
Device# configure terminal

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
75

RADIUS Change of Authorization
Monitoring and Troubleshooting RADIUS Change of Authorization

Step 3

Command or Action

Purpose

aaa new-model

Enables AAA globally.

Example:
Device(config)# aaa new-model

Step 4

aaa server radius dynamic-author
Example:
Device(config)# aaa server radius
dynamic-author

Sets up the local AAA server for the dynamic authorization service,
which must be enabled to support the CoA functionality to push the
policy map in an input and output direction, and enters dynamic
authorization local server configuration mode.
• In this mode, the RADIUS application commands are configured.

Step 5

client {ip-addr | hostname} [server-key [0 | 7] Configures the IP address or hostname of the AAA server client.
string]
• Use the optional server-key keyword and string argument to
configure the server key at the client level.
Example:

Device(config-locsvr-da-radius)# client
Note
192.168.0.5 server-key cisco1

Step 6

domain {delimiter character | stripping |
[right-to-left]}
Example:
Device(config-locsvr-da-radius)# domain
stripping right-to-left

Configuring the server key at the client level overrides the
server key configured at the global level.

(Optional) Configures username domain options for the RADIUS
application.
• The delimiter keyword specifies the domain delimiter. One of
the following options can be specified for the character
argument: @, /, $, %, \, #, or -.
• The stripping keyword compares the incoming username with
the names oriented to the left of the @ domain delimiter.
• The right-to-left keyword terminates the string at the first
delimiter going from right to left.

Step 7

port port-num

Configures the UDP port for CoA requests.

Example:
Device(config-locsvr-da-radius)# port
3799

Step 8

Returns to privileged EXEC mode.

end
Example:
Device(config-locsvr-da-radius)# end

Monitoring and Troubleshooting RADIUS Change of Authorization
The following commands can be used to monitor and troubleshoot the RADIUS Change of Authorization
feature:

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
76

RADIUS Change of Authorization
Configuration Examples for RADIUS Change of Authorization

Table 14: Monitoring and Troubleshooting RADIUS Change of Authorization

Command

Purpose

debug aaa coa

Displays debug information for
CoA processing.

debug aaa pod

Displays debug messages related
to packet of disconnect (POD)
packets.

debug radius

Displays information associated
with RADIUS.

show aaa attributes protocol radius

Displays the mapping between an
authentication, authorization, and
accounting (AAA) attribute number
and the corresponding AAA
attribute name.

Configuration Examples for RADIUS Change of Authorization
Example: Configuring RADIUS Change of Authorization
Device> enable
Device# configure terminal
Device(config)# aaa new-model
Device(config)# aaa server radius dynamic-author
Device(config-locsvr-da-radius)# client 10.0.0.1
Device(config-locsvr-da-radius)# server-key cisco123
Device(config-locsvr-da-radius)# port 3799
Device(config-locsvr-da-radius)# auth-type all
Device(config-locsvr-da-radius)# ignore session-key
Device(config-locsvr-da-radius)# ignore server-key
Device(config-locsvr-da-radius)# end

Example: Configuring a Device to Ignore Bounce and Disable a RADIUS
Requests
Device> enable
Device# configure terminal
Device(config)# aaa new-model
Device(config)# authentication command bounce-port ignore
Device(config)# authentication command disable-port ignore
Device(config)# end

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
77

RADIUS Change of Authorization
Example: Configuring the Dynamic Authorization Service for RADIUS CoA

Example: Configuring the Dynamic Authorization Service for RADIUS CoA
The following example shows how to configure the device as a authentication, authorization, and accounting
(AAA) server to support Change of Authorization (CoA) functionality that pushes the policy map in an input
and output direction:
Device> enable
Device# configure terminal
Device(config)# aaa new-model
Device(config)# aaa server radius dynamic-author
Device(config-locsvr-da-radius)# client 192.168.0.5 server-key cisco1
Device(config-locsvr-da-radius)# domain delimiter @
Device(config-locsvr-da-radius)# port 3799
Device(config-locsvr-da-radius)# end

Additional References for RADIUS Change of Authorization
Related Documents
Related Topic

Document Title

Cisco IOS commands

Cisco IOS Master Command List,
All Releases

Security commands

• Security Command
Reference: Commands A to
C
• Security Command
Reference: Commands D to
L
• Security Command
Reference: Commands M to
R
• Security Command
Reference: Commands S to
Z
Authentication, Authorization, and
Accounting Configuration Guide

Configuring AAA

Standards and RFCs
Standard/RFC

Title

RFC 2903

Generic AAA Architecture

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
78

RADIUS Change of Authorization
Feature Information for RADIUS Change of Authorization

Standard/RFC

Title

RFC 5176

Dynamic Authorization Extensions to Remote
Authentication Dial In User Service(RADIUS)

Technical Assistance
Description

Link

The Cisco Support and Documentation website
http://www.cisco.com/cisco/web/support/index.html
provides online resources to download documentation,
software, and tools. Use these resources to install and
configure the software and to troubleshoot and resolve
technical issues with Cisco products and technologies.
Access to most tools on the Cisco Support and
Documentation website requires a Cisco.com user ID
and password.

Feature Information for RADIUS Change of Authorization
The following table provides release information about the feature or features described in this module. This
table lists only the software release that introduced support for a given feature in a given software release
train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support.
To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
79

RADIUS Change of Authorization
Feature Information for RADIUS Change of Authorization

Table 15: Feature Information for RADIUS Change of Authorization

Feature Name

Releases

RADIUS Change of Authorization Cisco IOS XE 2.1

Feature Information
The RADIUS Change of
Authorization (CoA) feature
provides a mechanism to change
the attributes of an AAA session
after it is authenticated. When
policy changes for a user or user
group in AAA, administrators can
send the RADIUS CoA packets
from the AAA server, such as the
Cisco Secure Access Control
Server (ACS), to reinitialize
authentication and apply the new
policy.
The following commands were
introduced or modified: aaa server
radius dynamic-author,
authentication command
bounce-port ignore, and
authentication command
disable-port ignore.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
80

CHAPTER

Message Banners for AAA Authentication
The Message Banners for AAA authentication feature is used to configure personalized login and failed-login
banners for user authentication. The message banners are displayed when a user logs in to the system to be
authenticated using authentication, authorization, and accounting (AAA) and when an authentication fails.
• Finding Feature Information, page 81
• Information About Message Banners for AAA Authentication, page 81
• How to Configure Message Banners for AAA Authentication, page 82
• Configuration Examples for Message Banners for AAA Authentication, page 84
• Additional References for Message Banners for AAA Authentication, page 85
• Feature Information for Message Banners for AAA Authentication, page 86

Information About Message Banners for AAA Authentication
Login and Failed-Login Banners for AAA Authentication
Login and failed-login banners use a delimiting character that notifies the system of the exact text string that
must be displayed as the banner for authorization, authentication, and accounting (AAA) authentication. The
delimiting character is repeated at the end of the text string to signify the end of the login or failed-login

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
81

Message Banners for AAA Authentication
How to Configure Message Banners for AAA Authentication

banner. The delimiting character can be any single character in the extended ASCII character set, but once
defined as the delimiter, that character cannot be used in the text string for the banner.
You can display a maximum of 2996 characters in a login or failed-login banner.

How to Configure Message Banners for AAA Authentication
Configuring a Login Banner for AAA Authentication
Perform this task to configure a banner that is displayed when a user logs in (replacing the default message
for login). Use the no aaa authentication banner command to disable a login banner.

SUMMARY STEPS
1. enable
2. configure terminal
3. aaa new-model
4. aaa authentication banner delimiter-string delimiter
5. end

DETAILED STEPS

Step 1

Command or Action

Purpose

enable

Enables privileged EXEC mode.
• Enter your password if prompted.

Example:
Device> enable

Step 2

configure terminal

Enters global configuration mode.

Example:
Device# configure terminal

Step 3

aaa new-model

Enables AAA globally.

Example:
Device(config)# aaa new-model

Step 4

aaa authentication banner delimiter-string delimiter

Creates a personalized login banner.

Example:
Device(config)# aaa authentication banner
*Unauthorized Access Prohibited*

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
82

Message Banners for AAA Authentication
Configuring a Failed-Login Banner for AAA Authentication

Step 5

Command or Action

Purpose

end

Returns to privileged EXEC mode.

Example:
Device(config)# end

Configuring a Failed-Login Banner for AAA Authentication
Perform this task to configure a failed-login banner that is displayed when a user login fails (replacing the
default message for failed login). Use the no aaa authentication fail-message command to disable a
failed-login banner.

SUMMARY STEPS
1. enable
2. configure terminal
3. aaa new-model
4. aaa authentication banner delimiter-string delimiter
5. aaa authentication fail-message delimiter-string delimiter
6. end

DETAILED STEPS

Step 1

Command or Action

Purpose

enable

Enables privileged EXEC mode.
• Enter your password if prompted.

Example:
Device> enable

Step 2

Enters global configuration mode.

configure terminal
Example:
Device# configure terminal

Step 3

Enters AAA globally.

aaa new-model
Example:
Device(config)# aaa new-model

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
83

Message Banners for AAA Authentication
Configuration Examples for Message Banners for AAA Authentication

Step 4

Command or Action

Purpose

aaa authentication banner delimiter-string delimiter

Creates a personalized login banner.

Example:
Device(config)# aaa authentication banner *Unauthorized
Access Prohibited*

Step 5

aaa authentication fail-message delimiter-string delimiter

Creates a message to be displayed when a user
login fails.

Example:
Device(config)# aaa authentication fail-message *Failed
login. Try again*

Step 6

Returns to privileged EXEC mode.

end
Example:
Device(config)# end

Configuration Examples for Message Banners for AAA
Authentication
Example: Configuring Login and Failed-Login Banners for AAA Authentication
The following example shows how to configure a login banner that is displayed when a user logs in to the
system, (in this case, the phrase “Unauthorized Access Prohibited”). The asterisk (*) is used as the delimiting
character. RADIUS is specified as the default login authentication method.
Device> enable
Device# configure terminal
Device(config)# aaa new-model
Device(config)# aaa authentication banner *Unauthorized Access Prohibited*
Device(config)# aaa authentication login default group radius

This configuration displays the following login banner:
Unauthorized Access Prohibited
Username:

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
84

Message Banners for AAA Authentication
Additional References for Message Banners for AAA Authentication

Device(config)# aaa authentication banner *Unauthorized Access Prohibited*
Device(config)# aaa authentication fail-message *Failed login. Try again.*
Device(config)# aaa authentication login default group radius

This configuration displays the following login and failed-login banner:
Unauthorized Access Prohibited
Username:
Password:
Failed login. Try again.

Additional References for Message Banners for AAA
Authentication
Related Documents
Related Topic

Document Title

Cisco IOS commands

Cisco IOS Master Command List,
All Releases

Security commands

• Security Command
Reference: Commands A to
C
• Security Command
Reference: Commands D to
L
• Security Command
Reference: Commands M to
R
• Security Command
Reference: Commands S to
Z

Configuring AAA

Authentication, Authorization, and
Accounting Configuration Guide

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
85

Message Banners for AAA Authentication
Feature Information for Message Banners for AAA Authentication

Technical Assistance
Description

Link

Feature Information for Message Banners for AAA
Authentication
The following table provides release information about the feature or features described in this module. This
table lists only the software release that introduced support for a given feature in a given software release
train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support.
To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Table 16: Feature Information for Message Banners for AAA Authentication

Feature Name

Releases

Feature Information

Message Banners for AAA
Authentication

Cisco IOS XE 2.1

The Message Banners for AAA
Authentication feature enables you
to configure personalized login and
failed-login banners for user
authentication. The message
banners are displayed when a user
logs in to the system to be
authenticated using authentication,
authorization, and accounting
(AAA) and when an authentication
fails.
The following commands were
introduced or modified: aaa
authentication banner, aaa
authentication fail-message, and
aaa new-model.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
86

CHAPTER

AAA-Domain Stripping at Server Group Level
The AAA-Domain Stripping at Server Group Level feature allows domain stripping to be configured at the
server group level.
• Finding Feature Information, page 87
• Information About AAA-Domain Stripping at Server Group Level, page 87
• How to Configure AAA-Domain Stripping at Server Level Group, page 88
• Configuration Example for AAA-Domain Stripping at Server Group Level, page 89
• Additional References, page 89
• Feature Information for AAA-Domain Stripping at Server Group Level, page 91

Information About AAA-Domain Stripping at Server Group Level
You can remove the domain name from the username received at the global level by using the radius-server
domain-stripping command. When the radius-server domain-stripping command is configured, all the
AAA requests with “user@example.com” go to the remote RADIUS server with the reformatted username
“user”. The domain name is removed from the request.

Note

Domain stripping will not be done in a TACACS configuration.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
87

AAA-Domain Stripping at Server Group Level
How to Configure AAA-Domain Stripping at Server Level Group

The AAA Broadcast Accounting feature allows accounting information to be sent to multiple AAA servers
at the same time, that is, accounting information can be broadcast to one or more AAA servers simultaneously.
This functionality allows you to send accounting information to private and public AAA servers. It also
provides redundant billing information for voice applications.
You can configure domain stripping at the server group level by using the domain-stripping command in
server group RADIUS configuration mode. Per-server group configuration overrides the global configuration.
If domain stripping is not enabled globally, but it is enabled in a server group, then it is enabled only for that
server group. Also, if virtual routing and forwarding (VRF)-specific domain stripping is configured globally
and in a server group for a different VRF, domain stripping is enabled in both the VRFs. VRF configurations
are taken from server-group configuration mode. If server-group configurations are disabled in global
configuration mode but are available in server-group configuration mode, all configurations in server-group
configuration mode are applicable.
After the domain stripping and broadcast accounting are configured, you can create separate accounting
records as per the configurations.

How to Configure AAA-Domain Stripping at Server Level Group
Configuring Domain Stripping at the Server Group Level
SUMMARY STEPS
1. enable
2. configure terminal
3. aaa new-model
4. aaa group server radius server-name
5. domain-stripping [strip-suffix word] [right-to-left ] [prefix-delimiter word] [delimiter word]
6. end

DETAILED STEPS

Step 1

Command or Action

Purpose

enable

Enables privileged EXEC mode.

Example:

• Enter your password if prompted.

Device> enable

Step 2

configure terminal

Enters global configuration mode.

Example:
Device# configure terminal

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
88

AAA-Domain Stripping at Server Group Level
Configuration Example for AAA-Domain Stripping at Server Group Level

Step 3

Command or Action

Purpose

aaa new-model

Enables AAA.

Example:
Device(config)# aaa new-model

Step 4

aaa group server radius server-name
Example:
Device(config)# aaa group server radius rad1

Step 5

domain-stripping [strip-suffix word] [right-to-left ]
[prefix-delimiter word] [delimiter word]

Adds the RADIUS server and enters server group
RADIUS configuration mode.
• The server-name argument specifies the RADIUS
server group name.
Configures domain stripping at the server group level.

Example:
Device(config-sg-radius)# domain-stripping
delimiter username@example.com

Step 6

Exits server group RADIUS configuration mode and
returns to the privileged EXEC mode.

end
Example:
Device(config-sg-radius)# end

Configuration Example for AAA-Domain Stripping at Server
Group Level
Example: AAA-Domain Stripping at Server Group Level
The following example shows the domain stripping configuration at the server group level:
Device> enable
Device# configure terminal
Device(config)# aaa new-model
Device(config)# aaa group server radius rad1
Device(config-sg-radius)# domain-stripping right-to-left delimiter @$/
Device(config-sg-radius)# end

Additional References
The following sections provide references related to the Configuring Authentication feature.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
89

AAA-Domain Stripping at Server Group Level
Additional References

Related Documents
Related Topic

Document Title

AAA

Authentication, Authorization, and Accounting
(AAA) section of the Cisco IOS XE Security
Configuration Guide, Securing User Services, Release
2.

Security commands

Cisco IOS Security Command Reference

CLI Configuration

Cisco IOS XE Configuration Fundamentals
Configuration Guide, Release 2

Standards
Standard

Title

No new or modified standards are supported by this -feature, and support for existing standards has not
been modified by this feature.

MIBs
MIB

MIBs Link

No new or modified MIBs are supported by this
feature, and support for existing MIBs has not been
modified by this feature.

To locate and download MIBs for selected platforms,
Cisco IOS XE software releases, and feature sets, use
Cisco MIB Locator found at the following URL:
http://www.cisco.com/go/mibs

RFCs
RFC

Title

RFC 2865

Remote Authentication Dial-in User Service

RFC 3576

Dynamic Authorization Extensions to RADIUS

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
116

RADIUS Packet of Disconnect
Feature Information for RADIUS Packet of Disconnect

Technical Assistance
Description

Link

Feature Information for RADIUS Packet of Disconnect
The following table provides release information about the feature or features described in this module. This
table lists only the software release that introduced support for a given feature in a given software release
train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support.
To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Table 20: Feature Information for RADIUS Packet of Disconnect

Feature Name

Releases

Feature Information

RADIUS Packet of Disconnect

Cisco IOS XE Release 2.1

The RADIUS Packet of Disconnect
feature is used to terminate a
connected voice call.
In Cisco IOS XE Release 2.1, this
feature was introduced on the on
Cisco ASR 1000 Series
Aggregation Services Routers.
The following commands were
introduced or modified: aaa pod
server, debug aaa pod

Glossary
AAA --authentication, authorization, and accounting. A framework of security services that provide the method
for identifying users (authentication), for remote access control (authorization), and for collecting and sending
security server information used for billing, auditing, and reporting (accounting).

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
117

RADIUS Packet of Disconnect
Glossary

L2TP --Layer 2 Tunnel Protocol. A Layer 2 tunneling protocol that enables an ISP or other access service to
create a virtual tunnel to link customer remote sites or remote users with corporate home networks. In particular,
a network access server (NAS) at the ISP point of presence (POP) exchanges PPP messages with the remote
users and communicates by L2F or L2TP requests and responses with the customer tunnel server to set up
tunnels.
PE --Provider Edge. Networking devices that are located on the edge of a service provider network.
RADIUS --Remote Authentication Dial-In User Service. RADIUS is a distributed client/server system that
secures networks against unauthorized access. In the Cisco implementation, RADIUS clients run on Cisco
routers and send authentication requests to a central RADIUS server that contains all user authentication and
network service access information.
VPN --Virtual Private Network. A system that permits dial-in networks to exist remotely to home networks,
while giving the appearance of being directly connected. VPNs use L2TP and L2F to terminate the Layer 2
and higher parts of the network connection at the LNS instead of the LAC.
VRF --Virtual Route Forwarding. Initially, a router has only one global default routing/forwarding table.
VRFs can be viewed as multiple disjoined routing/forwarding tables, where the routes of a user have no
correlation with the routes of another user.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
118

CHAPTER

AAA Authorization and Authentication Cache
The AAA Authorization and Authentication Cache feature allows you to cache authorization and authentication
responses for a configured set of users or service profiles, providing performance improvements and an
additional level of network reliability because user and service profiles that are returned from authorization
and authentication responses can be queried from multiple sources and need not depend solely on an offload
server. This feature also provides a failover mechanism so that if a network RADIUS or TACACS+ server
is unable to provide authorization and authentication responses network users and administrators can still
access the network.
• Finding Feature Information, page 119
• Prerequisites for Implementing Authorization and Authentication Profile Caching, page 120
• Information About Implementing Authorization and Authentication Profile Caching, page 120
• How to Implement Authorization and Authentication Profile Caching, page 122
• Configuration Examples for Implementing Authorization and Authentication Profile Caching, page
128
• Additional References for RADIUS Change of Authorization, page 131
• Feature Information for Implementing Authorization and Authentication Profile Caching, page 132

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
119

AAA Authorization and Authentication Cache
Prerequisites for Implementing Authorization and Authentication Profile Caching

PrerequisitesforImplementingAuthorizationandAuthentication
Profile Caching
The following prerequisites apply to implementing authorization and authentication profile caching:
• Understand how you would want to implement profile caching, that is, are profiles being cached to
improve network performance or as a failover mechanism if your network authentication and authorization
(RADIUS and TACACS+) servers become unavailable.
• RADIUS and TACACS+ server groups must already be configured.

Information About Implementing Authorization and
Authentication Profile Caching
Network Performance Optimization Using Authorization and Authentication
Profile Caching
RADIUS and TACACS+ clients run on Cisco routers and send authentication requests to a central RADIUS
or TACACS+ server that contains all user authentication and network service access information. The router
is required to communicate with an offload RADIUS or TACACS+ server to authenticate a given call and
then apply a policy or service to that call. Unlike authentication, authorization, and accounting (AAA)
accounting, AAA authentication and authorization is a blocking procedure, which means the call setup may
not proceed while the call is being authenticated and authorized. Thus, the time required to process the call
setup is directly impacted by the time required to process such an authentication or authorization request from
the router to the offload RADIUS or TACACS+ server, and back again. Any communication problems in the
transmission, offload server utilization, and numerous other factors cause significant degradation in a router’s
call setup performance due simply to the AAA authentication and authorization step. The problem is further
highlighted when multiple AAA authentications and authorizations are needed for a single call or session.
A solution to this problem is to minimize the impact of such authentication requests by caching the
authentication and authorization responses for given users on the router, thereby removing the need to send
the requests to an offload server again and again. This profile caching adds significant performance
improvements to call setup times. Profile caching also provides an additional level of network reliability
because user and service profiles that are returned from authentication and authorization responses can be
queried from multiple sources and need not depend solely on an offload server.
To take advantage of this performance optimization, you need to configure the authentication method list so
that the AAA cache profile is queried first when a user attempts to authenticate to the router. See the Method
Lists in Authorization and Authentication Profile Caching section for more information.

Authorization and Authentication Profile Caching as a Failover Mechanism
If, for whatever reason, RADIUS or TACACS+ servers are unable to provide authentication and authorization
responses, network users and administrators can be locked out of the network. The profile caching feature

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
120

AAA Authorization and Authentication Cache
Method Lists in Authorization and Authentication Profile Caching

allows usernames to be authorized without having to complete the authentication phase. For example, a user
by the name of user100@example.com with a password secretpassword1 could be stored in a profile cache
using the regular expression “.*@example.com”. Another user by the name of user101@example.com with
a password of secretpassword2 could also be stored using the same regular expression, and so on. Because
the number of users in the “.*@example.com” profile could number in the thousands, it is not feasible to
authenticate each user with their personal password. Therefore authentication is disabled and each user simply
accesses authorization profiles from a common Access Response stored in cache.
The same reasoning applies in cases where higher end security mechanisms such as Challenge Handshake
Authentication Protocol (CHAP), Microsoft Challenge Handshake Authentication Protocol (MS-CHAP), or
Extensible Authentication Protocol (EAP), which all use an encrypted password between the client and AAA
offload server, are used. To allow these unique, secure username and password profiles to retrieve their
authorization profiles, authentication is bypassed.
To take advantage of this failover capability, you need to configure the authentication and authorization
method list so that the cache server group is queried last when a user attempts to authenticate to the router.
See the Method Lists in Authorization and Authentication Profile Caching section for more information.

Method Lists in Authorization and Authentication Profile Caching
A method list is a sequential list describing the authentication methods to be queried in order to authenticate
a user. We support methods such as local (use the local database), none (do nothing), RADIUS server group,
or TACACS+ server group. Typically, more than one method can be configured into a method list. software
uses the first listed method to authenticate users. If that method fails to respond, the software selects the next
authentication method listed in the method list. This process continues until there is successful communication
with a listed authentication method, or until all methods defined in the method list are exhausted.
To optimize network performance or provide failover capability using the profile caching feature you simply
change the order of the authentication and authorization methods in the method list. To optimize network
performance, make sure the cache server group appears first in the method list. For failover capability, the
cache server group should appear last in the method list.

Authorization and Authentication Profile Caching Guidelines
Because the number of usernames and profiles that can request to be authenticated or authorized at a given
router on a given point of presence (POP) can be quite extensive, it would not be feasible to cache all of them.
Therefore, only usernames and profiles that are commonly used or that share a common authentication and
authorization response should be configured to use caching. Commonly used usernames such as aolip and
aolnet, which are used for America Online (AOL) calls, or preauthentication dialed number identification
service (DNIS) numbers used to connect Public Switched Telephone Network (PSTN) calls to a network
attached storage device, along with domain-based service profiles, are all examples of usernames and profiles
that can benefit from authentication and authorization caching.

General Configuration Procedure for Implementing Authorization and
Authentication Profile Caching
To implement authorization and authentication profile caching, you would complete the following procedure:
1 Create cache profile groups and define the rules for what information is cached in each group.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
121

AAA Authorization and Authentication Cache
How to Implement Authorization and Authentication Profile Caching

Entries that match based on exact username, regular expressions, or specify that all authentication and
authorization requests can be cached.
1 Update existing server groups to reference newly defined cache groups.
2 Update authentication or authorization method lists to use the cached information to optimize network
performance or provide a failover mechanism.

How to Implement Authorization and Authentication Profile
Caching
Creating Cache Profile Groups and Defining Caching Rules
Perform this task to create a cache profile group, define the rules for what information is cached in that group,
and verify and manage cache profile entries.

SUMMARY STEPS
1. enable
2. configure terminal
3. aaa new-model
4. aaa cache profile group-name
5. profile name [no-auth]
6. Repeat Step 5 for each username you want to add to the profile group in Step 4.
7. regexp matchexpression {any| only}[no-auth]
8. Repeat Step 7 for each regular expression you want to add to the cache profile group defined in Step 4.
9. all [no-auth]
10. end
11. show aaa cache group
12. clear aaa cache group
13. debug aaa cache group

name
name {profile name| all}

DETAILED STEPS

Step 1

Command or Action

Purpose

enable

Enables privileged EXEC mode.

Example:

• Enter your password if prompted.

Router> enable

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
122

AAA Authorization and Authentication Cache
Creating Cache Profile Groups and Defining Caching Rules

Step 2

Command or Action

Purpose

configure terminal

Enters global configuration mode.

Example:
Router# configure terminal

Step 3

Enables the AAA access control model.

aaa new-model
Example:
Router(config)# aaa new-model

Step 4

aaa cache profile group-name

Defines an authentication and authorization cache profile server
group and enters profile map configuration mode.

Example:
Router(config)# aaa cache profile
networkusers@companyname

Step 5

profile name

Creates an individual authentication and authorization cache
profile based on a username match.

[no-auth]

Example:
Router(config-profile-map# profile
networkuser1 no-auth

• The name argument must be an exact match to a username
being queried by an authentication or authorization service
request.
• Use the no-auth keyword to bypass authentication for this
user.

Step 6

Repeat Step 5 for each username you want to add -to the profile group in Step 4.

Step 7

regexp matchexpression

{any| only}[no-auth] (Optional) Creates an entry in a cache profile group that matches
based on a regular expression.

Example:
Router(config-profile-map)# regexp
.*@example.com any no-auth

• If you use the any keyword, all unique usernames matching
the regular expression are saved.
• If you use the only keyword, only one profile entry is cached
for all usernames matching the regular expression.
• Use the no-auth keyword to bypass authentication for this
user or set of users.
• Because the number of entries in a regular expression cache
profile group could be in the thousands, and validating each
request against a regular expression can be time consuming,
we do not recommend using regular expression entries in
cache profile groups.

Step 8

Repeat Step 7 for each regular expression you want -to add to the cache profile group defined in Step 4.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
123

AAA Authorization and Authentication Cache
Defining RADIUS and TACACS Server Groups That Use Cache Profile Group Information

Step 9

Command or Action

Purpose

all [no-auth]

(Optional) Specifies that all authentication and authorization
requests are cached.

Example:
Router(config-profile-map)# all no-auth

Step 10

• Use the all command for specific service authorization
requests, but it should be avoided when dealing with
authentication requests.
Returns to privileged EXEC mode.

end
Example:
Router(config-profile-map)# end

Step 11

show aaa cache group

name

(Optional) Displays all cache entries for a specified group.

Example:
Router# show aaa cache group
networkusers@companyname

Step 12

clear aaa cache group
all}

name {profile name|

(Optional) Clears an individual entry or all entries in the cache.

Example:
Router# clear aaa cache group
networkusers@companyname profile
networkuser1

Step 13

debug aaa cache group

(Optional) Displays debug information about cached entries.

Example:
Router# debug aaa cache group

Defining RADIUS and TACACS Server Groups That Use Cache Profile Group
Information
Perform this task to define how RADIUS and TACACS+ server groups use the information stored in each
cache profile group.

Before You Begin
RADIUS and TACACS+ server groups must be created.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
124

AAA Authorization and Authentication Cache
Defining RADIUS and TACACS Server Groups That Use Cache Profile Group Information

SUMMARY STEPS
1. enable
2. configure terminal
3. aaa new-model
4. aaa group server radius group-name oraaa group server tacacs+ group-name
5. cache authorization profile
6. cache authentication profile

name
name

7. cache expiry hours {enforce failover}
8. end

DETAILED STEPS

Step 1

Command or Action

Purpose

enable

Enables privileged EXEC mode.
• Enter your password if prompted.

Example:
Router> enable

Step 2

Enters global configuration mode.

configure terminal
Example:
Router# configure terminal

Step 3

Enables the AAA access control model.

aaa new-model
Example:
Router(config)# aaa new-model

Step 4

aaa group server radius group-name oraaa group Enters RADIUS server group configuration mode.
server tacacs+ group-name
• To enter TACACS+ server group configuration mode, use
the aaa group server tacacs+ group-name command.
Example:

Router(config)# aaa group server radius
networkusers@companyname

Step 5

cache authorization profile

name

Example:
Router(config-sg-radius)# cache authorization
profile networkusers@companyname

Activates the authorization caching rules in the profile
networkusers for this RADIUS or TACACS+ server group.
• The name argument in this command is a AAA cache
profile group name.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
125

AAA Authorization and Authentication Cache
Updating Authorization and Authentication Method Lists to Specify How Cache Information is Used

Command or Action
Step 6

cache authentication profile

Purpose
name

Activates the authentication caching rules in the profile
networkusers for this RADIUS or TACACS+ server group.

Example:
Router(config-sq-radius)# cache
authentication profile
networkusers@companyname

Step 7

cache expiry hours {enforce failover}
Example:
Router(config-sq-radius)# cache expiry 240
failover

(Optional) Sets the amount of time before a cache profile entry
expires (becomes stale).
• Use the enforce keyword to specify that once a cache
profile entry expires it is not used again.
• Use the failover keyword to specify that an expired cache
profile entry can be used if all other methods to authenticate
and authorize the user fail.

Step 8

Returns to privileged EXEC mode.

end
Example:
Router(config-sg-radius)# end

Updating Authorization and Authentication Method Lists to Specify How Cache
Information is Used
Perform this task to update authorization and authentication method lists to use the authorization and
authentication cache information.

Before You Begin
Method lists must already be defined.

SUMMARY STEPS
1. enable
2. configure terminal
3. aaa new-model
4. aaa authorization {network | exec | commands level | reverse-access| configuration} {default |
list-name} [method1 [method2...]]
5. aaa authentication ppp {default | list-name} method1 [method2...]
6. aaa authentication login {default | list-name} method1 [method2...]
7. end

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
126

AAA Authorization and Authentication Cache
Updating Authorization and Authentication Method Lists to Specify How Cache Information is Used

DETAILED STEPS

Step 1

Command or Action

Purpose

enable

Enables privileged EXEC mode.
• Enter your password if prompted.

Example:
Router> enable

Step 2

Enters global configuration mode.

configure terminal
Example:
Router# configure terminal

Step 3

Enables the AAA access control model.

aaa new-model
Example:
Router(config)# aaa new-model

Step 4

Enables AAA authorization and creates method
aaa authorization {network | exec | commands level |
reverse-access| configuration} {default | list-name} [method1 lists, which define the authorization methods used
when a user accesses a specified function.
[method2...]]
Example:
Router(config)# aaa authorization network default cache
networkusers@companyname group
networkusers@companyname

Step 5

aaa authentication ppp {default | list-name} method1
[method2...]

Specifies one or more authentication methods for
use on serial interfaces that are running PPP.

Example:
Router(config)# aaa authentication ppp default cache
networkusers@companyname group networkusers@companyname

Step 6

aaa authentication login {default | list-name} method1
[method2...]

Sets the authentication at login.

Example:
Router(config)# aaa authentication login default cache
adminusers group adminusers

Step 7

end

Returns to privileged EXEC mode.

Example:
Router(config)# end

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
127

AAA Authorization and Authentication Cache
Configuration Examples for Implementing Authorization and Authentication Profile Caching

Configuration Examples for Implementing Authorization and
Authentication Profile Caching
Implementing Authorization and Authentication Profile Caching for Network
Optimization Example
The following configuration example shows how to:
• Define a cache profile group adminusers that contains all administrator names on the network and sets
it as the default list that is used for all login and exec sessions.
• Activate the new caching rules for a RADIUS server group.
• Add the new cache profile group in the authentication and authorization method list and change the
method order so that the cache profile group is queried first.
configure terminal
aaa new-model
! Define aaa cache profile groups and the rules for what information is saved to cache.
aaa cache profile admin_users
profile adminuser1
profile adminuser2
profile adminuser3
profile adminuser4
profile adminuser5
exit
! Define server groups that use the cache information in each profile group.
aaa group server radius admins@companyname.com
cache authorization profile admin_users
cache authentication profile admin_users
! Update authentication and authorization method lists to specify how profile groups and
server groups are used.
aaa authentication login default cache admins@companyname.com group admins@companyname.com
aaa authorization exec default cache admins@companyname.com group admins@companyname.com
end

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
128

AAA Authorization and Authentication Cache
Implementing Authorization and Authentication Profile Caching as a Failover Mechanism Example

Implementing Authorization and Authentication Profile Caching as a Failover
Mechanism Example
The following configuration example shows how to:
• Create a cache profile group admin_users that contains all of the administrators on the network so that
if the RADIUS or TACACS+ server should become unavailable the administrators can still access the
network.
• Create a cache profile group abc_users that contains all of the ABC company users on the network so
that if the RADIUS or TACACS+ server should become unavailable these users will be authorized to
use the network.
• Activate the new caching rules for each profile group on a RADIUS server.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
129

AAA Authorization and Authentication Cache
Implementing Authorization and Authentication Profile Caching as a Failover Mechanism Example

• Add the new cache profile group in the authentication and authorization method list and change the
method order so that the cache profile group is queried last.
configure terminal
aaa new-model
! Define aaa cache profile groups and the rules for what information is saved to cache.
aaa cache profile admin_users
profile admin1
profile admin2
profile admin3
exit
aaa cache profile abcusers
profile .*@example.com only no-auth
exit
! Define server groups that use the cache information in each cache profile group.
aaa group server tacacs+ admins@companyname.com
server 10.1.1.1
server 10.20.1.1
cache authentication profile admin_users
cache authorization profile admin_users
exit
aaa group server radius abcusers@example.com
server 172.16.1.1
server 172.20.1.1
cache authentication profile abcusers
cache authorization profile abcusers
exit
! Update authentication and authorization method lists to specify how cache is used.
aaa authentication login default cache admins@companyname.com group admins@companyname.com
aaa authorization exec default cache admins@companyname.com group admins@companyname.com
aaa authentication ppp default group abcusers@example.com cache abcusers@example.com
aaa authorization network default group abcusers@example.com cache abcusers@example.com
end

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
130

AAA Authorization and Authentication Cache
Additional References for RADIUS Change of Authorization

Additional References for RADIUS Change of Authorization
Related Documents
Related Topic

Document Title

Cisco IOS commands

Cisco IOS Master Command List,
All Releases

Security commands

Configuring AAA

Standards and RFCs
Standard/RFC

Title

RFC 2903

Generic AAA Architecture

RFC 5176

Dynamic Authorization Extensions to Remote
Authentication Dial In User Service(RADIUS)

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
131

AAA Authorization and Authentication Cache
Feature Information for Implementing Authorization and Authentication Profile Caching

Technical Assistance
Description

Link

Feature Information for Implementing Authorization and
Authentication Profile Caching
The following table provides release information about the feature or features described in this module. This
table lists only the software release that introduced support for a given feature in a given software release
train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support.
To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
132

AAA Authorization and Authentication Cache
Feature Information for Implementing Authorization and Authentication Profile Caching

Table 21: Feature Information for Implementing Authentication and Authorization Profile Caching

Feature Name

Release

Feature Information

AAA Authorization and
Authentication Cache

Cisco IOS XE Release 2.3

This feature optimizes network
performance and provides a
failover mechanism in the event a
network RADIUS or TACACS+
server becomes unavailable for any
reason.
In Cisco IOS XE Release 2.3, this
feature was introduced on the Cisco
ASR 1000 Series Aggregation
Services Routers.
The following commands were
introduced or modified: aaa
authentication login, aaa
authentication ppp, aaa
authorization, aaa cache profile,
all (profile map configuration),
cache authentication profile
(server group configuration),
cache authorization profile
(server group configuration),
cache expiry (server group
configuration), clear aaa cache
group, debug aaa cache group,
profile (profile map
configuration), regexp (profile
map configuration), show aaa
cache group.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
133

AAA Authorization and Authentication Cache
Feature Information for Implementing Authorization and Authentication Profile Caching

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
134

CHAPTER

Configuring Authorization
AAA authorization enables you to limit the services available to a user. When AAA authorization is enabled,
the network access server uses information retrieved from the user’s profile, which is located either in the
local user database or on the security server, to configure the user’s session. Once this is done, the user will
be granted access to a requested service only if the information in the user profile allows it.
• Finding Feature Information, page 135
• AAA Authorization Prerequisites, page 135
• Information About Configuring Authorization, page 136
• How to Configure Authorization, page 139
• Authorization Configuration Examples, page 142
• Additional References, page 145
• Feature Information for Configuring Authorization, page 146

AAA Authorization Prerequisites
Before configuring authorization using named method lists, you must first perform the following tasks:
• Enable AAA on your network access server.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
135

Configuring Authorization
Information About Configuring Authorization

• Configure AAA authentication. Authorization generally takes place after authentication and relies on
authentication to work properly. For more information about AAA authentication, refer to the “Configuring
Authentication” module.
• Define the characteristics of your RADIUS or TACACS+ security server if you are issuing RADIUS
or TACACS+ authorization. For more information about configuring your Cisco network access server
to communicate with your RADIUS security server, refer to the chapter “Configuring RADIUS”. For
more information about configuring your Cisco network access server to communicate with your
TACACS+ security server, refer to the “Configuring TACACS+” module.
• Define the rights associated with specific users by using the username command if you are issuing local
authorization. For more information about the username command, refer to the Cisco IOS Security
Command Reference .

Information About Configuring Authorization
Named Method Lists for Authorization
Method lists for authorization define the ways that authorization will be performed and the sequence in which
these methods will be performed. A method list is simply a named list describing the authorization methods
to be queried (such as RADIUS or TACACS+), in sequence. Method lists enable you to designate one or
more security protocols to be used for authorization, thus ensuring a backup system in case the initial method
fails. Cisco IOS XE software uses the first method listed to authorize users for specific network services; if
that method fails to respond, the Cisco IOS XE software selects the next method listed in the list. This process
continues until there is successful communication with a listed authorization method, or all methods defined
are exhausted.

Note

The Cisco IOS XE software attempts authorization with the next listed method only when there is no
response from the previous method. If authorization fails at any point in this cycle--meaning that the
security server or local username database responds by denying the user services--the authorization process
stops and no other authorization methods are attempted.
Method lists are specific to the authorization type requested:
• Commands--Applies to the EXEC mode commands a user issues. Command authorization attempts
authorization for all EXEC mode commands, including global configuration commands, associated with
a specific privilege level.
• EXEC--Applies to the attributes associated with a user EXEC terminal session.
• Network--Applies to network connections. This can include a PPP, SLIP, or ARAP connection.
• Reverse Access--Applies to reverse Telnet sessions.
When you create a named method list, you are defining a particular list of authorization methods for the
indicated authorization type.
Once defined, method lists must be applied to specific lines or interfaces before any of the defined methods
will be performed. The only exception is the default method list (which is named “default”). If the aaa
authorization command for a particular authorization type is issued without a named method list specified,

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
136

Configuring Authorization
AAA Authorization Methods

the default method list is automatically applied to all interfaces or lines except those that have a named method
list explicitly defined. (A defined method list overrides the default method list.) If no default method list is
defined, local authorization takes place by default.

AAA Authorization Methods
AAA supports five different methods of authorization:
• TACACS+—The network access server exchanges authorization information with the TACACS+
security daemon. TACACS+ authorization defines specific rights for users by associating attribute-value
pairs, which are stored in a database on the TACACS+ security server, with the appropriate user.
• If-Authenticated—The user is allowed to access the requested function provided the user has been
authenticated successfully.
• None—The network access server does not request authorization information; authorization is not
performed over this line/interface.
• Local—The router or access server consults its local database, as defined by the username command,
for example, to authorize specific rights for users. Only a limited set of functions can be controlled via
the local database.
• RADIUS—The network access server requests authorization information from the RADIUS security
server. RADIUS authorization defines specific rights for users by associating attributes, which are stored
in a database on the RADIUS server, with the appropriate user.

Note

With CSCuc32663, passwords and authorization logs are masked before being sent to the TACACS+,
LDAP, or RADIUS security servers. Use the aaa authorization commands visible-keys command to
send unmasked information to the TACACS+, LDAP, or RADIUS security servers.

Authorization Methods
To have the network access server request authorization information via a TACACS+ security server, use the
aaa authorization command with the group tacacs+ method keyword. For more specific information about
configuring authorization using a TACACS+ security server, refer to the chapter “Configuring TACACS+.”
For an example of how to enable a TACACS+ server to authorize the use of network services, including PPP
and ARA, see the TACACS Authorization Examples.
To allow users to have access to the functions they request as long as they have been authenticated, use the
aaa authorization command with the if-authenticated method keyword. If you select this method, all
requested functions are automatically granted to authenticated users.
There may be times when you do not want to run authorization from a particular interface or line. To stop
authorization activities on designated lines or interfaces, use the none method keyword. If you select this
method, authorization is disabled for all actions.
To select local authorization, which means that the router or access server consults its local user database to
determine the functions a user is permitted to use, use the aaa authorization command with the local method
keyword. The functions associated with local authorization are defined by using the username global
configuration command. For a list of permitted functions, refer to the chapter “Configuring Authentication.”

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
137

Configuring Authorization
Method Lists and Server Groups

To have the network access server request authorization via a RADIUS security server, use the radius method
keyword. For more specific information about configuring authorization using a RADIUS security server,
refer to the Configuring RADIUS chapter.
To have the network access server request authorization via a RADIUS security server, use the aaa
authorization command with the group radius method keyword. For more specific information about
configuring authorization using a RADIUS security server, refer to the chapter Configuring RADIUS. For an
example of how to enable a RADIUS server to authorize services, see the RADIUS Authorization Example.

Note

Authorization method lists for SLIP follow whatever is configured for PPP on the relevant interface. If
no lists are defined and applied to a particular interface (or no PPP settings are configured), the default
setting for authorization applies.

Method Lists and Server Groups
A server group is a way to group existing RADIUS or TACACS+ server hosts for use in method lists. The
figure below shows a typical AAA network configuration that includes four security servers: R1 and R2 are
RADIUS servers, and T1 and T2 are TACACS+ servers. R1 and R2 make up the group of RADIUS servers.
T1 and T2 make up the group of TACACS+ servers.
Using server groups, you can specify a subset of the configured server hosts and use them for a particular
service. For example, server groups allow you to define R1 and R2 as separate server groups, and T1 and T2
as separate server groups. This means you can specify either R1 and T1 in the method list or R2 and T2 in
the method list, which provides more flexibility in the way that you assign RADIUS and TACACS+ resources.
Server groups also can include multiple host entries for the same server, as long as each entry has a unique
identifier. The combination of an IP address and a UDP port number creates a unique identifier, allowing
different ports to be individually defined as RADIUS hosts providing a specific AAA service. In other words,
this unique identifier enables RADIUS requests to be sent to different UDP ports on a server at the same IP
address. If two different host entries on the same RADIUS server are configured for the same service--for
example, authorization--the second host entry configured acts as fail-over backup to the first one. Using this
example, if the first host entry fails to provide accounting services, the network access server will try the
second host entry configured on the same device for accounting services. (The RADIUS host entries will be
tried in the order they are configured.)
For more information about configuring server groups and about configuring server groups based on DNIS
numbers, refer to the chapter Configuring RADIUS or the chapter Configuring TACACS+.

AAA Authorization Types
Cisco IOS XE software supports five different types of authorization:
• Commands--Applies to the EXEC mode commands a user issues. Command authorization attempts
authorization for all EXEC mode commands, including global configuration commands, associated with
a specific privilege level.
• EXEC--Applies to the attributes associated with a user EXEC terminal session.
• Network--Applies to network connections. This can include a PPP, SLIP, or ARAP connection.
• Reverse Access--Applies to reverse Telnet sessions.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
138

Configuring Authorization
Authorization Attribute-Value Pairs

• Configuration--Applies to downloading configurations from the AAA server.
• IP Mobile--Applies to authorization for IP mobile services.

Authorization Types
Named authorization method lists are specific to the indicated type of authorization.
To create a method list to enable authorization that applies specific security policies on a per-user basis, use
the auth-proxy keyword. For detailed information on the authentication proxy feature, refer to the chapter
“Configuring Authentication Proxy” in the “Traffic Filtering and Firewalls” part of this book.
To create a method list to enable authorization for all network-related service requests (including SLIP, PPP,
PPP NCPs, and ARAP), use the network keyword.
To create a method list to enable authorization to determine if a user is allowed to run an EXEC shell, use the
exec keyword.
To create a method list to enable authorization for specific, individual EXEC commands associated with a
specific privilege level, use the commandskeyword. (This allows you to authorize all commands associated
with a specified command level from 0 to 15.)
To create a method list to enable authorization for reverse Telnet functions, use the reverse-access keyword.
For information about the types of authorization supported by the Cisco IOS XE software, refer to the AAA
Authorization Types.

Authorization Attribute-Value Pairs
RADIUS and TACACS+ authorization both define specific rights for users by processing attributes, which
are stored in a database on the security server. For both RADIUS and TACACS+, attributes are defined on
the security server, associated with the user, and sent to the network access server where they are applied to
the user’s connection.
For a list of supported RADIUS attributes, refer to the “RADIUS Attributes Overview and RADIUS IETF
Attributes” chapter. For a list of supported TACACS+ AV pairs, refer to the “Configuring TACACS+” chapter.

How to Configure Authorization
For authorization configuration examples using the commands in this chapter, refer to the Authorization
Configuration Examples.

Configuring AAA Authorization Using Named Method Lists
To configure AAA authorization using named method lists, use the following commands beginning in global
configuration mode:

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
139

Configuring Authorization
Configuring AAA Authorization Using Named Method Lists

SUMMARY STEPS
1. Router(config)# aaa authorization {auth-proxy | network | exec | commands level | reverse-access |
configuration | ipmobile} {default | list-name} [method1 [method2...]]
2. Do one of the following:
• Router(config)# line [aux | console | tty | vty] line-number [ending-line-number]
•
•
• Router(config)# interface interface-type interface-number
3. Do one of the following:
• Router(config-line)# authorization{arap | commands level | exec | reverse-access} {default |
list-name}
•
•
• Router(config-line)# ppp authorization{default | list-name}

DETAILED STEPS
Command or Action

Purpose

Step 1

Router(config)# aaa authorization {auth-proxy | network | Creates an authorization method list for a particular
authorization type and enable authorization.
exec | commands level | reverse-access | configuration |
ipmobile} {default | list-name} [method1 [method2...]]

Step 2

Do one of the following:
• Router(config)# line [aux | console | tty | vty]
line-number [ending-line-number]
•
•
• Router(config)# interface interface-type
interface-number

Step 3

Do one of the following:

Enters the line configuration mode for the lines to which
you want to apply the authorization method list.
Alternately, enters the interface configuration mode for
the interfaces to which you want to apply the authorization
method list.

Applies the authorization list to a line or set of lines.

• Router(config-line)# authorization{arap | commands Alternately, applies the authorization list to an interface
or set of interfaces.
level | exec | reverse-access} {default | list-name}
•
•
• Router(config-line)# ppp authorization{default |
list-name}

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
140

Configuring Authorization
Disabling Authorization for Global Configuration Commands

Disabling Authorization for Global Configuration Commands
The aaa authorization command with the keyword commands attempts authorization for all EXEC mode
commands, including global configuration commands, associated with a specific privilege level. Because
there are configuration commands that are identical to some EXEC-level commands, there can be some
confusion in the authorization process. Using no aaa authorization config-commands stops the network
access server from attempting configuration command authorization.
To disable AAA authorization for all global configuration commands, use the following command in global
configuration mode:
Command
Device(config)#

Purpose
no aaa authorization

config-commands

Disables authorization for all global configuration
commands.

To disable AAA authorization on the console, use the following command in global configuration mode:

Note

AAA authorization is disabled on the console by default. If AAA authorization is enabled on the console,
disable it by configuring the no aaa authorization console command during the AAA configuration stage.
AAA should be disabled on the console for user authentication.
Command
Device(config)#

Purpose
no aaa authorization console

Disables authorization on the console.

Configuring Authorization for Reverse Telnet
Telnet is a standard terminal emulation protocol used for remote terminal connection. Normally, you log in
to a network access server (typically through a dialup connection) and then use Telnet to access other network
devices from that network access server. There are times, however, when it is necessary to establish a reverse
Telnet session. In reverse Telnet sessions, the Telnet connection is established in the opposite direction--from
inside a network to a network access server on the network periphery to gain access to modems or other
devices connected to that network access server. Reverse Telnet is used to provide users with dialout capability
by allowing them to Telnet to modem ports attached to a network access server.
It is important to control access to ports accessible through reverse Telnet. Failure to do so could, for example,
allow unauthorized users free access to modems where they can trap and divert incoming calls or make
outgoing calls to unauthorized destinations.
Authentication during reverse Telnet is performed through the standard AAA login procedure for Telnet.
Typically the user has to provide a username and password to establish either a Telnet or reverse Telnet
session. Reverse Telnet authorization provides an additional (optional) level of security by requiring
authorization in addition to authentication. When enabled, reverse Telnet authorization can use RADIUS or

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
141

Configuring Authorization
Authorization Configuration Examples

TACACS+ to authorize whether or not this user is allowed reverse Telnet access to specific asynchronous
ports, after the user successfully authenticates through the standard Telnet login procedure.
Reverse Telnet authorization offers the following benefits:
• An additional level of protection by ensuring that users engaged in reverse Telnet activities are indeed
authorized to access a specific asynchronous port using reverse Telnet.
• An alternative method (other than access lists) to manage reverse Telnet authorization.
To configure a network access server to request authorization information from a TACACS+ or RADIUS
server before allowing a user to establish a reverse Telnet session, use the following command in global
configuration mode:
Command

Purpose

aaa authorization
reverse-access method1 [method2 ...]

Configures the network access server to request
authorization information before allowing a user to
establish a reverse Telnet session.

Router(config)#

This feature enables the network access server to request reverse Telnet authorization information from the
security server, whether RADIUS or TACACS+. You must configure the specific reverse Telnet privileges
for the user on the security server itself.

Authorization Configuration Examples
TACACS Authorization Examples
The following examples show how to use a TACACS+ server to authorize the use of network services,
including PPP and ARA. If the TACACS+ server is not available or an error occurs during the authorization
process, the fallback method (none) is to grant all authorization requests:
aaa authorization network default group tacacs+ none

The following example shows how to allow network authorization using TACACS+:
aaa authorization network default group tacacs+

The following example shows how to provide the same authorization, but it also creates address pools called
“mci” and “att” :
aaa authorization network default group tacacs+
ip address-pool local
ip local-pool mci 172.16.0.1 172.16.0.255
ip local-pool att 172.17.0.1 172.17.0.255

These address pools can then be selected by the TACACS daemon. A sample configuration of the daemon
follows:
user = mci_customer1 {
login = cleartext “some password”
service = ppp protocol = ip {
addr-pool=mci
}
}

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
142

Configuring Authorization
RADIUS Authorization Example

user = att_customer1 {
login = cleartext “some other password”
service = ppp protocol = ip {
addr-pool=att
}

RADIUS Authorization Example
The following example shows how to configure the router to authorize using RADIUS:
aaa new-model
aaa authorization exec default group radius if-authenticated
aaa authorization network default group radius
radius-server host ip
radius-server key

The lines in this sample RADIUS authorization configuration are defined as follows:
• The aaa authorization exec default group radius if-authenticated command configures the network
access server to contact the RADIUS server to determine if users are permitted to start an EXEC shell
when they log in. If an error occurs when the network access server contacts the RADIUS server, the
fallback method is to permit the CLI to start, provided the user has been properly authenticated.
The RADIUS information returned may be used to specify an autocommand or a connection access list be
applied to this connection.
• The aaa authorization network default group radius command configures network authorization via
RADIUS. This can be used to govern address assignment, the application of access lists, and various
other per-user quantities.

Note

Because no fallback method is specified in this example, authorization will fail if, for any reason, there
is no response from the RADIUS server.

Reverse Telnet Authorization Examples
The following examples show how to cause the network access server to request authorization information
from a TACACS+ security server before allowing a user to establish a reverse Telnet session:
aaa new-model
aaa authentication login default group tacacs+
aaa authorization reverse-access default group tacacs+
!
tacacs-server host 172.31.255.0
tacacs-server timeout 90
tacacs-server key goaway

The lines in this sample TACACS+ reverse Telnet authorization configuration are defined as follows:
• The aaa new-model command enables AAA.
• The aaa authentication login default group tacacs+ command specifies TACACS+ as the default
method for user authentication during login.
• The aaa authorization reverse-access default group tacacs+ command specifies TACACS+ as the
method for user authorization when trying to establish a reverse Telnet session.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
143

Configuring Authorization
Reverse Telnet Authorization Examples

• The tacacs-server host command identifies the TACACS+ server.
• The tacacs-server timeoutcommand sets the interval of time that the network access server waits for
the TACACS+ server to reply.
• The tacacs-server key command defines the encryption key used for all TACACS+ communications
between the network access server and the TACACS+ daemon.
The following example shows how to configure a generic TACACS+ server to grant a user, pat, reverse Telnet
access to port tty2 on the network access server named “maple” and to port tty5 on the network access server
named “oak”:
user = pat
login = cleartext lab
service = raccess {
port#1 = maple/tty2
port#2 = oak/tty5

Note

In this example, “maple” and “oak” are the configured host names of network access servers, not DNS
names or alias.
The following example shows how to configure the TACACS+ server (CiscoSecure) to grant a user named
pat reverse Telnet access:
user = pat
profile_id = 90
profile_cycle = 1
member = Tacacs_Users
service=shell {
default cmd=permit
}
service=raccess {
allow “c2511e0” “tty1” “.*”
refuse “.*” “.*” “.*”
password = clear “goaway”

Note

CiscoSecure only supports reverse Telnet using the command line interface in versions 2.1(x) through
version 2.2(1).
An empty “service=raccess {}” clause permits a user to have unconditional access to network access server
ports for reverse Telnet. If no “service=raccess” clause exists, the user is denied access to any port for reverse
Telnet.
For more information about configuring TACACS+, refer to the “Configuring TACACS” chapter. For more
information about configuring CiscoSecure, refer to the CiscoSecure Access Control Server User Guide ,
version 2.1(2) or greater.
The following example shows how to cause the network access server to request authorization from a RADIUS
security server before allowing a user to establish a reverse Telnet session:
aaa new-model
aaa authentication login default group radius
aaa authorization reverse-access default group radius
!
radius-server host 172.31.255.0
radius-server key go away
auth-port 1645 acct-port 1646

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
144

Configuring Authorization
Additional References

The lines in this sample RADIUS reverse Telnet authorization configuration are defined as follows:
• The aaa new-model command enables AAA.
• The aaa authentication login default group radius command specifies RADIUS as the default method
for user authentication during login.
• The aaa authorization reverse-access default group radius command specifies RADIUS as the method
for user authorization when trying to establish a reverse Telnet session.
• The radius-server host command identifies the RADIUS server.
• The radius-server key command defines the encryption key used for all RADIUS communications
between the network access server and the RADIUS daemon.
The following example shows how to send a request to the RADIUS server to grant a user named “pat” reverse
Telnet access at port tty2 on the network access server named “maple”:
Username = “pat”
Password = “goaway”
User-Service-Type = Shell-User
cisco-avpair = “raccess:port#1=maple/tty2”

The syntax "raccess:port=any/any" permits a user to have unconditional access to network access server ports
for reverse Telnet. If no "raccess:port={nasname }/{tty number }" clause exists in the user profile, the user
is denied access to reverse Telnet on all ports.
For more information about configuring RADIUS, refer to the chapter “Configuring RADIUS.”

Additional References
Related Documents
Related Topic

Document Title

Cisco IOS commands

Master Command List, All
Releases

Security commands

• Security Command
Reference: Commands A to
C
• Security Command
Reference: Commands D to
L
• Security Command
Reference: Commands M to
R
• Security Command
Reference: Commands S to
Z

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
145

Configuring Authorization
Feature Information for Configuring Authorization

Technical Assistance
Description

Link

Feature Information for Configuring Authorization
The following table provides release information about the feature or features described in this module. This
table lists only the software release that introduced support for a given feature in a given software release
train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support.
To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Table 22: Feature Information for Configuring Authorization

Feature Name

Releases

Feature Information

Named Method Lists for AAA
Authorization and Accounting

Cisco IOS XE Release 2.1

Method lists for authorization
define the ways that authorization
will be performed and the sequence
in which these methods will be
performed. A method list is simply
a named list describing the
authorization methods to be
queried (such as RADIUS or
TACACS+), in sequence.
In Cisco IOS XE Release 2.1, this
feature was introduced on the Cisco
ASR 1000 Series Aggregation
Services Routers.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
146

CHAPTER

Configuring Accounting
The AAA accounting feature allows the services that users are accessing and the amount of network resources
that users are consuming to be tracked. When AAA accounting is enabled, the network access server reports
user activity to the TACACS+ or RADIUS security server (depending on which security method is
implemented) in the form of accounting records. Each accounting record contains accounting attribute-value
(AV) pairs and is stored on the security server. This data can then be analyzed for network management,
client billing, and auditing.
• Finding Feature Information, page 147
• Prerequisites for Configuring Accounting, page 147
• Restrictions for Configuring Accounting, page 148
• Information About Configuring Accounting, page 148
• How to Configure AAA Accounting, page 162
• Configuration Examples for AAA Accounting, page 171
• Additional References, page 174
• Feature Information for Configuring Accounting, page 176

Prerequisites for Configuring Accounting
The following tasks must be performed before configuring accounting using named method lists:

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
147

Configuring Accounting
Restrictions for Configuring Accounting

• Enable AAA on the network access server.
• Define the characteristics of the RADIUS or TACACS+ security server if RADIUS or TACACS+
authorization is issued. For more information about configuring the Cisco network access server to
communicate with the RADIUS security server, see the chapter Configuring RADIUS. For more
information about configuring the Cisco network access server to communicate with the TACACS+
security server, see the chapter Configuring TACACS+.

Restrictions for Configuring Accounting
The AAA Accounting feature has the following restrictions:
• Accounting information can be sent simultaneously to a maximum of four AAA servers.
• Service Selection Gateway (SSG) restriction--For SSG systems, the aaa accounting network broadcast
command broadcasts only start-stop accounting records. If interim accounting records are configured
using thessg accounting interval command, the interim accounting records are sent only to the configured
default RADIUS server.

Information About Configuring Accounting
Named Method Lists for Accounting
Like authentication and authorization method lists, method lists for accounting define the way accounting is
performed and the sequence in which these methods are performed.
Named accounting method lists allow a particular security protocol to be designated and used on specific lines
or interfaces for accounting services. The only exception is the default method list (which, by coincidence, is
named “default”). The default method list is automatically applied to all interfaces except those that have a
named method list explicitly defined. A defined method list overrides the default method list.
A method list is a named list describing the accounting methods to be queried (such as RADIUS or TACACS+),
in sequence. Method lists allow one or more security protocols to be designated and used for accounting, thus
ensuring a backup system for accounting if the initial method fails. Cisco IOS XE software uses the first
method listed to support accounting; if that method fails to respond, the Cisco IOS XE software selects the
next accounting method listed in the method list. This process continues until there is successful communication
with a listed accounting method, or all methods defined are exhausted.

Note

The Cisco IOS XE software attempts accounting with the next listed accounting method only when there
is no response from the previous method. If accounting fails at any point in this cycle--meaning that the
security server responds by denying the user access--the accounting process stops and no other accounting
methods are attempted.
Accounting method lists are specific to the type of accounting being requested. AAA supports six different
types of accounting:
• Network--Provides information for all PPP, SLIP, or ARAP sessions, including packet and byte counts.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
148

Configuring Accounting
Named Method Lists for Accounting

• EXEC--Provides information about user EXEC terminal sessions of the network access server.
• Command--Provides information about the EXEC mode commands that a user issues. Command
accounting generates accounting records for all EXEC mode commands, including global configuration
commands, associated with a specific privilege level.
• Connection--Provides information about all outbound connections made from the network access server,
such as Telnet, local-area transport (LAT), TN3270, packet assembler/disassembler (PAD), and rlogin.
• System--Provides information about system-level events.
• Resource--Provides “start” and “stop” records for calls that have passed user authentication, and provides
“stop” records for calls that fail to authenticate.

Note

System accounting does not use named accounting lists; only the default list for system accounting can
be defined.
When a named method list is created, a particular list of accounting methods for the indicated accounting type
are defined.
Accounting method lists must be applied to specific lines or interfaces before any of the defined methods are
performed. The only exception is the default method list (which is named “default”). If the aaa accounting
command for a particular accounting type is issued without a named method list specified, the default method
list is automatically applied to all interfaces or lines except those that have a named method list explicitly
defined. (A defined method list overrides the default method list.) If no default method list is defined, then
no accounting takes place.
This section includes the following subsections:

Method Lists and Server Groups
A server group is a way to group existing RADIUS or TACACS+ server hosts for use in method lists. The
figure below shows a typical AAA network configuration that includes four security servers: R1 and R2 are
RADIUS servers, and T1 and T2 are TACACS+ servers. R1 and R2 comprise the group of RADIUS servers.
T1 and T2 comprise the group of TACACS+ servers.
In Cisco IOS XE software, RADIUS and TACACS+ server configurations are global. A subset of the configured
server hosts can be specified using server groups. These server groups can be used for a particular service.
For example, server groups allow R1 and R2 to be defined as separate server groups (SG1 and SG2), and T1
and T2 as separate server groups (SG3 and SG4). This means either R1 and T1 (SG1 and SG3) can be specified
in the method list or R2 and T2 (SG2 and SG4) in the method list, which provides more flexibility in the way
that RADIUS and TACACS+ resources are assigned.
Server groups also can include multiple host entries for the same server, as long as each entry has a unique
identifier. The combination of an IP address and a UDP port number creates a unique identifier, allowing
different ports to be individually defined as RADIUS hosts providing a specific AAA service. In other words,
this unique identifier enables RADIUS requests to be sent to different UDP ports on a server at the same IP
address. If two different host entries on the same RADIUS server are configured for the same service--for
example, accounting--the second host entry configured acts as failover backup to the first one. Using this
example, if the first host entry fails to provide accounting services, the network access server tries the second
host entry configured on the same device for accounting services. (The RADIUS host entries are tried in the
order in which they are configured.)

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
149

Configuring Accounting
Named Method Lists for Accounting

For more information about configuring server groups and about configuring server groups based on DNIS
numbers, see Configuring RADIUS module or Configuring TACACS+ module in the Cisco IOS XE Security
Configuration Guide: Securing User Services Release 2.

AAA Accounting Methods
Cisco IOS XE supports the following two methods for accounting:
• TACACS+—The network access server reports user activity to the TACACS+ security server in the
form of accounting records. Each accounting record contains accounting attribute-value (AV) pairs and
is stored on the security server.
• RADIUS—The network access server reports user activity to the RADIUS security server in the form
of accounting records. Each accounting record contains accounting attribute-value (AV) pairs and is
stored on the security server.

Note

With CSCuc32663, passwords and accounting logs are masked before being sent to the TACACS+ or
RADIUS security servers. Use the aaa accounting commands visible-keys command to send unmasked
information to the TACACS+ or RADIUS security servers.

Accounting Record Types
For minimal accounting, use the stop-only keyword, which instructs the specified method (RADIUS or
TACACS+) to send a stop record accounting notice at the end of the requested user process. For more
accounting information, use the start-stop keyword to send a start accounting notice at the beginning of the
requested event and a stop accounting notice at the end of the event. To stop all accounting activities on this
line or interface, use the none keyword.

Accounting Methods
The table below lists the supported accounting keywords.
Table 23: AAA Accounting Methods

Keyword

Description

group radius

Uses the list of all RADIUS servers for accounting.

group tacacs+

Uses the list of all TACACS+ servers for accounting.

group group-name

Uses a subset of RADIUS or TACACS+ servers for
accounting as defined by the server group
group-name.

The method argument refers to the actual method the authentication algorithm tries. Additional methods of
authentication are used only if the previous method returns an error, not if it fails. To specify that the
authentication should succeed even if all other methods return an error, specify additional methods in the

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
150

Configuring Accounting
AAA Accounting Types

command. For example, to create a method list named acct_tac1 that specifies RADIUS as the backup method
of authentication in the event that TACACS+ authentication returns an error, enter the following command:
aaa accounting network acct_tac1 stop-only group tacacs+ group radius

To create a default list that is used when a named list is not specified in the aaa accountingcommand, use
the default keyword followed by the methods that are wanted to be used in default situations. The default
method list is automatically applied to all interfaces.
For example, to specify RADIUS as the default method for user authentication during login, enter the following
command:
aaa accounting network default stop-only group radius

AAA accounting supports the following methods:
• group tacacs --To have the network access server send accounting information to a TACACS+ security
server, use the group tacacs+ method keyword.
• group radius --To have the network access server send accounting information to a RADIUS security
server, use the group radius method keyword.

Note

Accounting method lists for SLIP follow whatever is configured for PPP on the relevant interface. If no
lists are defined and applied to a particular interface (or no PPP settings are configured), the default setting
for accounting applies.
• group group-name --To specify a subset of RADIUS or TACACS+ servers to use as the accounting
method, use the aaa accountingcommand with the group group-name method. To specify and define
the group name and the members of the group, use the aaa group server command. For example, use
the aaa group server command to first define the members of group loginrad:
aaa group server radius loginrad
server 172.16.2.3
server 172.16.2 17
server 172.16.2.32

This command specifies RADIUS servers 172.16.2.3, 172.16.2.17, and 172.16.2.32 as members of the group
loginrad.
To specify group loginrad as the method of network accounting when no other method list has been defined,
enter the following command:
aaa accounting network default start-stop group loginrad

Before a group name can be used as the accounting method, communication with the RADIUS or TACACS+
security server must be enabled.

AAA Accounting Types
Named accounting method lists are specific to the indicated type of accounting.
• network --To create a method list to enable authorization for all network-related service requests
(including SLIP, PPP, PPP NCPs, and ARAP protocols), use the network keyword. For example, to
create a method list that provides accounting information for ARAP (network) sessions, use the arap
keyword.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
151

Configuring Accounting
AAA Accounting Types

• exec --To create a method list that provides accounting records about user EXEC terminal sessions on
the network access server, including username, date, start and stop times, use the exec keyword.
• commands --To create a method list that provides accounting information about specific, individual
EXEC commands associated with a specific privilege level, use the commandskeyword.
• connection --To create a method list that provides accounting information about all outbound connections
made from the network access server, use the connection keyword.
• resource --To creates a method list to provide accounting records for calls that have passed user
authentication or calls that failed to be authenticated.

Note

System accounting does not support named method lists.

Network Accounting
Network accounting provides information for all PPP, SLIP, or ARAP sessions, including packet and byte
counts.
The following example shows the information contained in a RADIUS network accounting record for a PPP
user who comes in through an EXEC session:
Wed Jun 27 04:44:45 2001
NAS-IP-Address = “172.16.25.15”
NAS-Port = 5
User-Name = “username1”
Client-Port-DNIS = “4327528”
Caller-ID = “562”
Acct-Status-Type = Start
Acct-Authentic = RADIUS
Service-Type = Exec-User
Acct-Session-Id = “0000000D”
Acct-Delay-Time = 0
User-Id = “username1”
NAS-Identifier = “172.16.25.15”
Wed Jun 27 04:45:00 2001
NAS-IP-Address = “172.16.25.15”
NAS-Port = 5
User-Name = “username1”
Client-Port-DNIS = “4327528”
Caller-ID = “562”
Acct-Status-Type = Start
Acct-Authentic = RADIUS
Service-Type = Framed
Acct-Session-Id = “0000000E”
Framed-IP-Address = “10.1.1.2”
Framed-Protocol = PPP
Acct-Delay-Time = 0
User-Id = “username1”
NAS-Identifier = “172.16.25.15”
Wed Jun 27 04:47:46 2001
NAS-IP-Address = “172.16.25.15”
NAS-Port = 5
User-Name = “username1”
Client-Port-DNIS = “4327528”
Caller-ID = “562”
Acct-Status-Type = Stop
Acct-Authentic = RADIUS

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
152

Configuring Accounting
AAA Accounting Types

Service-Type = Framed
Acct-Session-Id = “0000000E”
Framed-IP-Address = “10.1.1.2”
Framed-Protocol = PPP
Acct-Input-Octets = 3075
Acct-Output-Octets = 167
Acct-Input-Packets = 39
Acct-Output-Packets = 9
Acct-Session-Time = 171
Acct-Delay-Time = 0
User-Id = “username1”
NAS-Identifier = “172.16.25.15”
Wed Jun 27 04:48:45 2001
NAS-IP-Address = “172.16.25.15”
NAS-Port = 5
User-Name = “username1”
Client-Port-DNIS = “4327528”
Caller-ID = “408”
Acct-Status-Type = Stop
Acct-Authentic = RADIUS
Service-Type = Exec-User
Acct-Session-Id = “0000000D”
Acct-Delay-Time = 0
User-Id = “username1”
NAS-Identifier = “172.16.25.15”

The following example shows the information contained in a TACACS+ network accounting record for a
PPP user who first started an EXEC session:
Wed Jun 27 04:00:35 2001 172.16.25.15
username1
tty4
562/4327528
starttask_id=28
service=shell
Wed Jun 27 04:00:46 2001 172.16.25.15
username1
tty4 562/4327528
starttask_id=30
addr=10.1.1.1
service=ppp
Wed Jun 27 04:00:49 2001 172.16.25.15
username1
tty4
408/4327528
update
task_id=30
addr=10.1.1.1
service=ppp
protocol=ip
addr=10.1.1.1
Wed Jun 27 04:01:31 2001 172.16.25.15
username1
tty4
562/4327528
stoptask_id=30
addr=10.1.1.1
service=ppp
protocol=ip
addr=10.1.1.1
bytes_in=2844
bytes_out=1682 paks_in=36
paks_out=24
elapsed_time=51
Wed Jun 27 04:01:32 2001 172.16.25.15
username1
tty4
562/4327528
stoptask_id=28
service=shell
elapsed_time=57

Note

The precise format of accounting packets records may vary depending on the security server daemon.
The following example shows the information contained in a RADIUS network accounting record for a PPP
user who comes in through autoselect:
Wed Jun 27 04:30:52 2001
NAS-IP-Address = “172.16.25.15”
NAS-Port = 3
User-Name = “username1”
Client-Port-DNIS = “4327528”
Caller-ID = “562”
Acct-Status-Type = Start
Acct-Authentic = RADIUS
Service-Type = Framed
Acct-Session-Id = “0000000B”
Framed-Protocol = PPP
Acct-Delay-Time = 0
User-Id = “username1”
NAS-Identifier = “172.16.25.15”
Wed Jun 27 04:36:49 2001
NAS-IP-Address = “172.16.25.15”
NAS-Port = 3
User-Name = “username1”
Client-Port-DNIS = “4327528”

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
153

Configuring Accounting
AAA Accounting Types

Caller-ID = “562”
Acct-Status-Type = Stop
Acct-Authentic = RADIUS
Service-Type = Framed
Acct-Session-Id = “0000000B”
Framed-Protocol = PPP
Framed-IP-Address = “10.1.1.1”
Acct-Input-Octets = 8630
Acct-Output-Octets = 5722
Acct-Input-Packets = 94
Acct-Output-Packets = 64
Acct-Session-Time = 357
Acct-Delay-Time = 0
User-Id = “username1”
NAS-Identifier = “172.16.25.15”

The following example shows the information contained in a TACACS+ network accounting record for a
PPP user who comes in through autoselect:
Wed Jun 27 04:02:19 2001 172.16.25.15
username1
Async5 562/4327528
starttask_id=35
service=ppp
Wed Jun 27 04:02:25 2001 172.16.25.15
username1
Async5 562/4327528
update
task_id=35
service=ppp
protocol=ip
addr=10.1.1.2
Wed Jun 27 04:05:03 2001 172.16.25.15
username1
Async5 562/4327528
stoptask_id=35
service=ppp
protocol=ip
addr=10.1.1.2
bytes_in=3366
bytes_out=2149
paks_in=42
paks_out=28
elapsed_time=164

EXEC Accounting
EXEC accounting provides information about user EXEC terminal sessions (user shells) on the network access
server, including username, date, start and stop times, the access server IP address, and (for dial-in users) the
telephone number the call originated from.
The following example shows the information contained in a RADIUS EXEC accounting record for a dial-in
user:
Wed Jun 27 04:26:23 2001
NAS-IP-Address = “172.16.25.15”
NAS-Port = 1
User-Name = “username1”
Client-Port-DNIS = “4327528”
Caller-ID = “5622329483”
Acct-Status-Type = Start
Acct-Authentic = RADIUS
Service-Type = Exec-User
Acct-Session-Id = “00000006”
Acct-Delay-Time = 0
User-Id = “username1”
NAS-Identifier = “172.16.25.15”
Wed Jun 27 04:27:25 2001
NAS-IP-Address = “172.16.25.15”
NAS-Port = 1
User-Name = “username1”
Client-Port-DNIS = “4327528”
Caller-ID = “5622329483”
Acct-Status-Type = Stop
Acct-Authentic = RADIUS
Service-Type = Exec-User
Acct-Session-Id = “00000006”
Acct-Session-Time = 62
Acct-Delay-Time = 0
User-Id = “username1”
NAS-Identifier = “172.16.25.15”

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
154

Configuring Accounting
AAA Accounting Types

The following example shows the information contained in a TACACS+ EXEC accounting record for a dial-in
user:
Wed Jun 27 03:46:21 2001
172.16.25.15
username1
start
task_id=2
service=shell
Wed Jun 27 04:08:55 2001
172.16.25.15
username1
stop
task_id=2
service=shell
elapsed_time=1354

tty3

5622329430/4327528

tty3

5622329430/4327528

The following example shows the information contained in a RADIUS EXEC accounting record for a Telnet
user:
Wed Jun 27 04:48:32 2001
NAS-IP-Address = “172.16.25.15”
NAS-Port = 26
User-Name = “username1”
Caller-ID = “10.68.202.158”
Acct-Status-Type = Start
Acct-Authentic = RADIUS
Service-Type = Exec-User
Acct-Session-Id = “00000010”
Acct-Delay-Time = 0
User-Id = “username1”
NAS-Identifier = “172.16.25.15”
Wed Jun 27 04:48:46 2001
NAS-IP-Address = “172.16.25.15”
NAS-Port = 26
User-Name = “username1”
Caller-ID = “10.68.202.158”
Acct-Status-Type = Stop
Acct-Authentic = RADIUS
Service-Type = Exec-User
Acct-Session-Id = “00000010”
Acct-Session-Time = 14
Acct-Delay-Time = 0
User-Id = “username1”
NAS-Identifier = “172.16.25.15”

The following example shows the information contained in a TACACS+ EXEC accounting record for a Telnet
user:
Wed Jun 27 04:06:53 2001
172.16.25.15
username1
starttask_id=41
service=shell
Wed Jun 27 04:07:02 2001
172.16.25.15
username1
stoptask_id=41
service=shell
elapsed_time=9

tty26

10.68.202.158

tty26

10.68.202.158

Command Accounting
Command accounting provides information about the EXEC shell commands for a specified privilege level
that are being executed on a network access server. Each command accounting record includes a list of the
commands executed for that privilege level, as well as the date and time each command was executed, and
the user who executed it.
The following example shows the information contained in a TACACS+ command accounting record for
privilege level 1:
Wed Jun 27 03:46:47 2001
172.16.25.15
username1
tty3
5622329430/4327528
stop
task_id=3
service=shell
priv-lvl=1
cmd=show version
Wed Jun 27 03:46:58 2001
172.16.25.15
username1
tty3
5622329430/4327528
stop
task_id=4
service=shell
priv-lvl=1
cmd=show interfaces
Wed Jun 27 03:47:03 2001
172.16.25.15
username1
tty3
5622329430/4327528
stop
task_id=5
service=shell
priv-lvl=1
cmd=show ip route

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
155

Configuring Accounting
AAA Accounting Types

The following example shows the information contained in a TACACS+ command accounting record for
privilege level 15:
Wed Jun 27 03:47:17 2001
172.16.25.15
username1
tty3
5622329430/4327528
stop
task_id=6
service=shell
priv-lvl=15
cmd=configure terminal
Wed Jun 27 03:47:21 2001
172.16.25.15
username1
tty3
5622329430/4327528
stop
task_id=7
service=shell
priv-lvl=15
cmd=interface GigabitEthernet0/0/0

Wed Jun 27 03:47:29 2001
172.16.25.15
username1
tty3
56223294304327528 stop
task_id=8
service=shell
priv-lvl=15
cmd=ip address 10.1.1.1 255.255.255.0

Note

The Cisco Systems implementation of RADIUS does not support command accounting.

Connection Accounting
Connection accounting provides information about all outbound connections made from the network access
server, such as Telnet, LAT, TN3270, PAD, and rlogin.
The following example shows the information contained in a RADIUS connection accounting record for an
outbound Telnet connection:
Wed Jun 27 04:28:00 2001
NAS-IP-Address = “172.16.25.15”
NAS-Port = 2
User-Name = “username1”
Client-Port-DNIS = “4327528”
Caller-ID = “5622329477”
Acct-Status-Type = Start
Acct-Authentic = RADIUS
Service-Type = Login
Acct-Session-Id = “00000008”
Login-Service = Telnet
Login-IP-Host = “10.68.202.158”
Acct-Delay-Time = 0
User-Id = “username1”
NAS-Identifier = “172.16.25.15”
Wed Jun 27 04:28:39 2001
NAS-IP-Address = “172.16.25.15”
NAS-Port = 2
User-Name = “username1”
Client-Port-DNIS = “4327528”
Caller-ID = “5622329477”
Acct-Status-Type = Stop
Acct-Authentic = RADIUS
Service-Type = Login
Acct-Session-Id = “00000008”
Login-Service = Telnet
Login-IP-Host = “10.68.202.158”
Acct-Input-Octets = 10774
Acct-Output-Octets = 112
Acct-Input-Packets = 91
Acct-Output-Packets = 99
Acct-Session-Time = 39
Acct-Delay-Time = 0
User-Id = “username1”
NAS-Identifier = “172.16.25.15”

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
156

Configuring Accounting
AAA Accounting Types

The following example shows the information contained in a TACACS+ connection accounting record for
an outbound Telnet connection:
Wed Jun 27 03:47:43 2001
172.16.25.15
username1
tty3
5622329430/4327528
start
task_id=10
service=connection
protocol=telnet addr=10.68.202.158 cmd=telnet
username1-sun
Wed Jun 27 03:48:38 2001
172.16.25.15
username1
tty3
5622329430/4327528
stop
task_id=10
service=connection
protocol=telnet addr=10.68.202.158 cmd=telnet
username1-sun
bytes_in=4467
bytes_out=96
paks_in=61
paks_out=72 elapsed_time=55

The following example shows the information contained in a RADIUS connection accounting record for an
outbound rlogin connection:
Wed Jun 27 04:29:48 2001
NAS-IP-Address = “172.16.25.15”
NAS-Port = 2
User-Name = “username1”
Client-Port-DNIS = “4327528”
Caller-ID = “5622329477”
Acct-Status-Type = Start
Acct-Authentic = RADIUS
Service-Type = Login
Acct-Session-Id = “0000000A”
Login-Service = Rlogin
Login-IP-Host = “10.68.202.158”
Acct-Delay-Time = 0
User-Id = “username1”
NAS-Identifier = “172.16.25.15”
Wed Jun 27 04:30:09 2001
NAS-IP-Address = “172.16.25.15”
NAS-Port = 2
User-Name = “username1”
Client-Port-DNIS = “4327528”
Caller-ID = “5622329477”
Acct-Status-Type = Stop
Acct-Authentic = RADIUS
Service-Type = Login
Acct-Session-Id = “0000000A”
Login-Service = Rlogin
Login-IP-Host = “10.68.202.158”
Acct-Input-Octets = 18686
Acct-Output-Octets = 86
Acct-Input-Packets = 90
Acct-Output-Packets = 68
Acct-Session-Time = 22
Acct-Delay-Time = 0
User-Id = “username1”
NAS-Identifier = “172.16.25.15”

The following example shows the information contained in a TACACS+ connection accounting record for
an outbound rlogin connection:
Wed Jun 27 03:48:46 2001
172.16.25.15
username1
tty3
5622329430/4327528
start
task_id=12
service=connection
protocol=rlogin addr=10.68.202.158 cmd=rlogin
username1-sun /user username1
Wed Jun 27 03:51:37 2001
172.16.25.15
username1
tty3
5622329430/4327528
stop
task_id=12
service=connection
protocol=rlogin addr=10.68.202.158 cmd=rlogin
username1-sun /user username1 bytes_in=659926 bytes_out=138
paks_in=2378
paks_
out=1251
elapsed_time=171

The following example shows the information contained in a TACACS+ connection accounting record for
an outbound LAT connection:
Wed Jun 27 03:53:06 2001
172.16.25.15
start
task_id=18
service=connection
VAX

username1
tty3
5622329430/4327528
protocol=lat
addr=VAX
cmd=lat

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
157

Configuring Accounting
AAA Accounting Types

Wed Jun 27 03:54:15 2001
172.16.25.15
stop
task_id=18
service=connection
VAX bytes_in=0
bytes_out=0
paks_in=0

username1
tty3
5622329430/4327528
protocol=lat
addr=VAX
cmd=lat
paks_out=0
elapsed_time=6

System Accounting
System accounting provides information about all system-level events (for example, when the system reboots
or when accounting is turned on or off).
The following accounting record shows a typical TACACS+ system accounting record server indicating that
AAA accounting has been turned off:
Wed Jun 27 03:55:32 2001
172.16.25.15
unknown unknown unknown start
service=system event=sys_acct reason=reconfigure

Note

task_id=25

The precise format of accounting packets records may vary depending on the TACACS+ daemon.
The following accounting record shows a TACACS+ system accounting record indicating that AAA accounting
has been turned on:
Wed Jun 27 03:55:22 2001
172.16.25.15
unknown unknown unknown stop
service=system event=sys_acct reason=reconfigure

task_id=23

Additional tasks for measuring system resources are covered in the Cisco IOS XE software configuration
guides. For example, IP accounting tasks are described in the Configuring IP Services chapter in the CiscoIOS
XE Application Services Configuration Guide, Release 2.

Resource Accounting
The Cisco implementation of AAA accounting provides “start” and “stop” record support for calls that have
passed user authentication. The additional feature of generating “stop” records for calls that fail to authenticate
as part of user authentication is also supported. Such records are necessary for users employing accounting
records to manage and monitor their networks.
This section includes the following subsections:

AAA Resource Failure Stop Accounting
Before AAA resource failure stop accounting, there was no method of providing accounting records for calls
that failed to reach the user authentication stage of a call setup sequence. Such records are necessary for users
employing accounting records to manage and monitor their networks and their wholesale customers.
This functionality generates a “stop” accounting record for any calls that do not reach user authentication;
“stop” records are generated from the moment of call setup. All calls that pass user authentication behave as
they did before; that is, no additional accounting records are seen.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
158

Configuring Accounting
AAA Accounting Types

The figure below illustrates a call setup sequence with normal call flow (no disconnect) and without AAA
resource failure stop accounting enabled.
Figure 4: Modem Dial-In Call Setup Sequence with Normal Flow and Without Resource Failure Stop Accounting Enabled

The figure below illustrates a call setup sequence with normal call flow (no disconnect) and with AAA resource
failure stop accounting enabled.
Figure 5: Modem Dial-In Call Setup Sequence with Normal Flow and wIth Resource Failure Stop Accounting Enabled

The figure below illustrates a call setup sequence with call disconnect occurring before user authentication
and with AAA resource failure stop accounting enabled.
Figure 6: Modem Dial-In Call Setup Sequence with Call Disconnect Occurring Before User Authentication and with
Resource Failure Stop Accounting Enabled

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
159

Configuring Accounting
AAA Accounting Enhancements

The figure below illustrates a call setup sequence with call disconnect occurring before user authentication
and without AAA resource failure stop accounting enabled.
Figure 7: Modem Dial-In Call Setup Sequence with Call Disconnect Occurring Before User Authentication and Without
Resource Failure Stop Accounting Enabled

AAA Resource Accounting for Start-Stop Records
AAA resource accounting for start-stop records supports the ability to send a “start” record at each call setup,
followed by a corresponding “stop” record at the call disconnect. This functionality can be used to manage
and monitor wholesale customers from one source of data reporting, such as accounting records.
With this feature, a call setup and call disconnect “start-stop” accounting record tracks the progress of the
resource connection to the device. A separate user authentication “start-stop” accounting record tracks the user
management progress. These two sets of accounting records are interlinked by using a unique session ID for
the call.
The figure below illustrates a call setup sequence with AAA resource start-stop accounting enabled.
Figure 8: Modem Dial-In Call Setup Sequence with Resource Start-Stop Accounting Enabled

AAA Accounting Enhancements
AAA Broadcast Accounting
AAA broadcast accounting allows accounting information to be sent to multiple AAA servers at the same
time; that is, accounting information can be broadcast to one or more AAA servers simultaneously. This
functionality allows service providers to send accounting information to their own private AAA servers and
to the AAA servers of their end customers. It also provides redundant billing information for voice applications.
Broadcasting is allowed among groups of RADIUS or TACACS+ servers, and each server group can define
its backup servers for failover independently of other groups.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
160

Configuring Accounting
AAA Accounting Enhancements

Thus, service providers and their end customers can use different protocols (RADIUS or TACACS+) for the
accounting server. Service providers and their end customers can also specify their backup servers
independently. As for voice applications, redundant accounting information can be managed independently
through a separate group with its own failover sequence.

AAA Session MIB
The AAA session MIB feature allows customers to monitor and terminate their authenticated client connections
using Simple Network Management Protocol (SNMP). The data of the client is presented so that it correlates
directly to the AAA accounting information reported by either the RADIUS or the TACACS+ server. AAA
session MIB provides the following information:
• Statistics for each AAA function (when used in conjunction with the show radius statistics command)
• Status of servers providing AAA functions
• Identities of external AAA servers
• Real-time information (such as idle times), providing additional criteria for use by SNMP networks for
assessing whether to terminate an active call
The table below shows the SNMP user-end data objects that can be used to monitor and terminate authenticated
client connections with the AAA session MIB feature.
Table 24: SNMP End-User Data Objects

Field

Descriptions

SessionId

The session identification used by the AAA
accounting protocol (same value as reported by
RADIUS attribute 44 (Acct-Session-ID)).

UserId

The user login ID or zero-length string if a login is
unavailable.

IpAddr

The IP address of the session or 0.0.0.0 if an IP
address is not applicable or unavailable.

IdleTime

The elapsed time in seconds that the session has been
idle.

Disconnect

The session termination object used to disconnect the
given client.

CallId

The entry index corresponding to this accounting
session that the Call Tracker record stored.

The table below describes the AAA summary information provided by the AAA session MIB feature using
SNMP on a per-system basis.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
161

Configuring Accounting
Accounting Attribute-Value Pairs

Table 25: SNMP AAA Session Summary

Field

Descriptions

ActiveTableEntries

Number of sessions currently active.

ActiveTableHighWaterMark

Maximum number of sessions present since last
system reinstallation.

TotalSessions

Total number of sessions since the last system
reinstallation.

DisconnectedSessions

Total number of sessions that have been disconnected
since the last system reinstallation.

Accounting Attribute-Value Pairs
The network access server monitors the accounting functions defined in either TACACS+ attribute-value
(AV) pairs or RADIUS attributes, depending on which security method is implemented.

How to Configure AAA Accounting
Configuring AAA Accounting Using Named Method Lists
To configure AAA accounting using named method lists, use the following commands beginning in global
configuration mode:

SUMMARY STEPS
1. Router(config)# aaa accounting {system | network | exec | connection | commands level} {default |
list-name} {start-stop | stop-only | none} [method1 [method2...]]
2. Do one of the following:
• Router(config)# line [aux | console | tty | vty] line-number [ending-line-number]
•
•
•
3. Do one of the following:
• Router(config-line)# accounting {arap | commands level | connection | exec} {default | list-name}
•
•
•

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
162

Configuring Accounting
Suppressing Generation of Accounting Records for Null Username Sessions

DETAILED STEPS
Command or Action

Purpose

Step 1

Router(config)# aaa accounting {system | network | exec | Creates an accounting method list and enables accounting.
The list-name argument is a character string used to name
connection | commands level} {default | list-name}
the created list.
{start-stop | stop-only | none} [method1 [method2...]]

Step 2

Do one of the following:
• Router(config)# line [aux | console | tty | vty]
line-number [ending-line-number]

Enters line configuration mode for the lines to which the
accounting method list is applied.
or
Enters interface configuration mode for the interfaces to
which the accounting method list is applied.

•
•
•
Example:
Router(config)#

Step 3

interface interface-type interface-number

Do one of the following:

Applies the accounting method list to a line or set of lines.

• Router(config-line)# accounting {arap | commands
level | connection | exec} {default | list-name}
•
•
•

or
Applies the accounting method list to an interface or set
of interfaces.

Example:
Router(config-if)#

ppp accounting {default

list-name}

What to Do Next

Note

System accounting does not use named method lists. For system accounting, define only the default method
list.

Suppressing Generation of Accounting Records for Null Username Sessions
When AAA accounting is activated, the Cisco IOS XE software issues accounting records for all users on the
system, including users whose username string, because of protocol translation, is NULL. An example of this
is users who come in on lines where the aaa authentication login method-list none command is applied. To

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
163

Configuring Accounting
Generating Interim Accounting Records

prevent accounting records from being generated for sessions that do not have usernames associated with
them, use the following command in global configuration mode:
Command or Action
Router(config)#

Purpose

aaa accounting suppress

null-username

Prevents accounting records from being generated
for users whose username string is NULL.

Generating Interim Accounting Records
To enable periodic interim accounting records to be sent to the accounting server, use the following command
in global configuration mode:
Command or Action
Router(config)# aaa accounting
[newinfo] [periodic] number

Purpose
update

Enables periodic interim accounting records to be
sent to the accounting server.

When the aaa accounting updatecommandis activated, the Cisco IOS XE software issues interim accounting
records for all users on the system. If the newinfo keyword is used, interim accounting records are sent to the
accounting server every time there is new accounting information to report. An example of this would be
when Internet Protocol Control Protocol (IPCP) completes IP address negotiation with the remote peer. The
interim accounting record includes the negotiated IP address used by the remote peer.
When aaa accounting updatecommand is used with the keyword periodic, interim accounting records are
sent periodically as defined by the argument number. The interim accounting record contains all of the
accounting information recorded for that user up to the time the interim accounting record is sent.

Caution

Using the aaa accounting update periodic command can cause heavy congestion when many users are
logged in to the network.

Configuring an Alternate Method to Enable Periodic Accounting Records
You can use the following alternative method to enable periodic interim accounting records to be sent to the
accounting server.

SUMMARY STEPS
1. enable
2. configure terminal
3. aaa accounting network default
4. action-type {none | start-stop [periodic {disable | interval minutes}] | stop-only}
5. exit

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
164

Configuring Accounting
Generating Interim Service Accounting Records

DETAILED STEPS

Step 1

Command or Action

Purpose

enable

Enables privileged EXEC mode.
• Enter your password if prompted.

Example:
Router> enable

Step 2

Enters global configuration mode.

configure terminal
Example:
Router# configure terminal

Step 3

aaa accounting network default

Configures the default accounting for all network-related service
requests and enters accounting method list configuration mode.

Example:
Router(config)# aaa accounting network
default

Step 4

action-type {none | start-stop [periodic {disable Specifies the type of action to be performed on accounting records.
| interval minutes}] | stop-only}
• (Optional) The periodic keyword specifies periodic
accounting action.
Example:

Step 5

Router(cfg-acct-mlist)# action-type
start-stop

• The interval keyword specifies the periodic accounting
interval.

Example:

• The value argument specifies the intervals for accounting
update records (in minutes).

periodic interval 5

• The disable keyword disables periodic accounting.
Returns to global configuration mode.

exit
Example:
Router(cfg-acct-mlist)# exit

Generating Interim Service Accounting Records
Perform this task to enable the generation of interim service accounting records at periodic intervals for
subscribers.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
165

Configuring Accounting
Generating Accounting Records for a Failed Login or Session

Before You Begin
RADIUS Attribute 85 in the user service profile always takes precedence over the configured interim-interval
value. RADIUS Attribute 85 must be in the user service profile. See the RADIUS Attributes Overview and
RADIUS IETF Attributes feature document for more information.

Note

If RADIUS Attribute 85 is not in the user service profile, then the interim-interval value configured in
Generating Interim Accounting Records is used for service interim accounting records.

SUMMARY STEPS
1. enable
2. configure terminal
3. subscriber service accounting interim-interval minutes

DETAILED STEPS

Step 1

Command or Action

Purpose

enable

Enables privileged EXEC mode.

Example:

• Enter your password if prompted.

Router> enable

Step 2

configure terminal

Enters global configuration mode.

Example:
Router# configure terminal

Step 3

subscriber service accounting interim-interval
minutes
Example:

Enables the generation of interim service accounting records at
periodic intervals for subscribers. The minutes argument
indicates the number of periodic intervals to send accounting
update records from 1 to 71582 minutes.

Router(config)# subscriber service
accounting interim-interval 10

Generating Accounting Records for a Failed Login or Session
When AAA accounting is activated, the Cisco IOS XE software does not generate accounting records for
system users who fail login authentication, or who succeed in login authentication but fail PPP negotiation
for some reason.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
166

Configuring Accounting
Specifying Accounting NETWORK-Stop Records Before EXEC-Stop Records

To specify that accounting stop records be generated for users who fail to authenticate at login or during
session negotiation, use the following command in global configuration mode:
Command or Action

Purpose

aaa accounting send
stop-record authentication failure

Generates “stop” records for users who fail to
authenticate at login or during session negotiation
using PPP.

Router(config)#

Specifying Accounting NETWORK-Stop Records Before EXEC-Stop Records
For PPP users who start EXEC terminal sessions, it can be specified that NETWORK records be generated
before EXEC-stop records. In some cases, such as billing customers for specific services, is can be desirable
to keep network start and stop records together, essentially “nesting” them within the framework of the EXEC
start and stop messages. For example, a user dialing in using PPP can create the following records: EXEC-start,
NETWORK-start, EXEC-stop, NETWORK-stop. By nesting the network accounting records, NETWORK-stop
records follow NETWORK-start messages: EXEC-start, NETWORK-start, NETWORK-stop, EXEC-stop.
To nest accounting records for user sessions, use the following command in global configuration mode:
Command or Action
Router(config)#

Purpose

aaa accounting nested

Nests network accounting records.

Suppressing System Accounting Records over Switchover
To suppress the system accounting-on and accounting-off messages during switchover, use the following
command in global configuration mode:
Command or Action

Purpose

aaa accounting redundancy
suppress system-records
Router(config)#

Suppresses the system accounting messages during
switchover.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
167

Configuring Accounting
Configuring AAA Resource Failure Stop Accounting

Configuring AAA Resource Failure Stop Accounting
To enable resource failure stop accounting, use the following command in global configuration:
Command or Action
aaa accounting resource
method-list stop-failure group server-group
Router(config)#

Purpose
Generates a “stop” record for any calls that do not
reach user authentication.
Note

Before configuring the AAA Resource
Failure Stop Accounting feature, the tasks
described in thePrerequisites for Configuring
Accounting, on page 147 section must be
performed, and SNMP must be enabled on
the network access server. For more
information about enabling SNMP on a Cisco
ASR 1000 Series Aggregation Services
Router, see the Configuring SNMP Support
chapter in the Cisco IOS XE Network
Management Configuration Guide.

Configuring AAA Resource Accounting for Start-Stop Records
To enable full resource accounting for start-stop records, use the following command in global configuration
mode:
Command or Action

Purpose

aaa accounting resource
method-list start-stop group server-group

Supports the ability to send a “start” record at each
call setup. followed with a corresponding “stop”
record at the call disconnect.

Router(config)#

Note

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
168

Before configuring this feature, the tasks
described in the section Prerequisites for
Configuring Accounting, on page 147 must
be performed, and SNMP must be enabled
on the network access server. For more
information about enabling SNMP on a
Cisco ASR 1000 Series Aggregation
Services Router, see the chapter Configuring
SNMP Support in the Cisco IOS XE
Network Management Configuration Guide,
Release 2.

Configuring Accounting
Configuring AAA Broadcast Accounting

Configuring AAA Broadcast Accounting
To configure AAA broadcast accounting, use the aaa accounting command in global configuration mode.
This command has been modified to allow the broadcast keyword.
Command or Action

Purpose

Router(config)# aaa accounting {system |
network | exec | connection | commands level}
{default | list-name} {start-stop | stop-only |
none} [broadcast] method1 [method2...]

Enables sending accounting records to multiple AAA
servers. Simultaneously sends accounting records to
the first server in each group. If the first server is
unavailable, failover occurs using the backup servers
defined within that group.

Configuring per-DNIS AAA Broadcast Accounting
To configure AAA broadcast accounting per DNIS, use the aaa dnis map accounting networkcommand in
global configuration mode. This command has been modified to allow the broadcast keyword and multiple
server groups.
Command or Action

Purpose

aaa dnis map dnis-number
accounting network [start-stop | stop-only |
none] [broadcast] method1 [method2...]
Router(config)#

Allows per-DNIS accounting configuration. This
command has precedence over the global aaa
accounting command.
Enables sending accounting records to multiple AAA
servers. Simultaneously sends accounting records to
the first server in each group. If the first server is
unavailable, failover occurs using the backup servers
defined within that group.

Configuring the AAA Session MIB
The following tasks must be performed before configuring the AAA session MIB feature:
• Configure SNMP. For information on SNMP, see the Configuring SNMP Support chapter in the Cisco
IOS XE Network Management Configuration Guide.
• Configure AAA.
• Define the RADIUS or TACACS+ server characteristics.

Note

Overusing SNMP can affect the overall system performance; therefore, normal network management
performance must be considered when this feature is used.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
169

Configuring Accounting
Establishing a Session with a Router if the AAA Server Is Unreachable

To configure the AAA session MIB, use the following command in global configuration mode:
Command or Action
Router(config)#

aaa session-mib disconnect

Purpose
Monitors and terminates authenticated client
connections using SNMP.
To terminate the call,use the disconnect keyword .

Establishing a Session with a Router if the AAA Server Is Unreachable
To establish a console session with a router if the AAA server is unreachable, use the following command in
global configuration mode:
Command or Action
Router(config)#

no aaa accounting system

guarantee-first

Purpose
The aaa accounting system guarantee-first
command guarantees system accounting as the first
record, which is the default condition.
In some situations, users may be prevented from
starting a session on the console or terminal
connection until after the system reloads, which can
take more than three minutes. To resolve this problem,
use the no aaa accounting system guarantee-first
command.

Monitoring Accounting
No specific show command exists for either RADIUS or TACACS+ accounting. To obtain accounting records
displaying information about users logged in, use the following command in privileged EXEC mode:
Command or Action
Router#

show accounting

Purpose
Allows display of the active accountable events on
the network and helps collect information in the event
of a data loss on the accounting server.

Troubleshooting Accounting
To troubleshoot accounting information, use the following command in privileged EXEC mode:
Command or Action
Router#

debug aaa accounting

Purpose
Displays information on accountable events as they
occur.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
170

Configuring Accounting
Configuration Examples for AAA Accounting

Configuration Examples for AAA Accounting
Configuring a Named Method List Example
The following example shows how to configure a Cisco AS5200 (enabled for AAA and communication with
a RADIUS security server) in order for AAA services to be provided by the RADIUS server. If the RADIUS
server fails to respond, then the local database is queried for authentication and authorization information,
and accounting services are handled by a TACACS+ server.
aaa new-model
aaa authentication login admins local
aaa authentication ppp dialins group radius local
aaa authorization network network1 group radius local
aaa accounting network network2 start-stop group radius group tacacs+
username root password ALongPassword
tacacs-server host 172.31.255.0
tacacs-server key goaway
radius-server host 172.16.2.7
radius-server key myRaDiUSpassWoRd
interface group-async 1
group-range 1 16
encapsulation ppp
ppp authentication chap dialins
ppp authorization network1
ppp accounting network2
line 1 16
autoselect ppp
autoselect during-login
login authentication admins
modem dialin

The lines in this sample RADIUS AAA configuration are defined as follows:
• The aaa new-model command enables AAA network security services.
• The aaa authentication login admins local command defines a method list, “admins”, for login
authentication.
• The aaa authentication ppp dialins group radius local command defines the authentication method
list “dialins”, which specifies that first RADIUS authentication and then (if the RADIUS server does not
respond) local authentication is used on serial lines using PPP.
• The aaa authorization network network1 group radius local command defines the network
authorization method list named “network1”, which specifies that RADIUS authorization is used on
serial lines using PPP. If the RADIUS server fails to respond, then local network authorization is
performed.
• The aaa accounting network network2 start-stop group radius group tacacs+command defines the
network accounting method list named “network2”, which specifies that RADIUS accounting services
(in this case, start and stop records for specific events) are used on serial lines using PPP. If the RADIUS
server fails to respond, accounting services are handled by a TACACS+ server.
• The username command defines the username and password to be used for the PPP Password
Authentication Protocol (PAP) caller identification.
• The tacacs-server host command defines the name of the TACACS+ server host.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
171

Configuring Accounting
Configuring a Named Method List Example

• The tacacs-server key command defines the shared secret text string between the network access server
and the TACACS+ server host.
• The radius-server host command defines the name of the RADIUS server host.
• The radius-server key command defines the shared secret text string between the network access server
and the RADIUS server host.
• The interface group-async command selects and defines an asynchronous interface group.
• The group-range command defines the member asynchronous interfaces in the interface group.
• The encapsulation ppp command sets PPP as the encapsulation method used on the specified interfaces.
• The ppp authentication chap dialinscommand selects Challenge Handshake Authentication Protocol
(CHAP) as the method of PPP authentication and applies the “dialins” method list to the specified
interfaces.
• The ppp authorization network1command applies the blue1 network authorization method list to the
specified interfaces.
• The ppp accounting network2command applies the red1 network accounting method list to the specified
interfaces.
• The line command switches the configuration mode from global configuration to line configuration and
identifies the specific lines being configured.
• The autoselect ppp command configures the Cisco IOS XE software to allow a PPP session to start up
automatically on these selected lines.
• The autoselect during-login command is used to display the username and password prompt without
pressing the Return key. After the user logs in, the autoselect function (in this case, PPP) begins.
• The login authentication admins command applies the admins method list for login authentication.
• The modem dialin command configures modems attached to the selected lines to accept only incoming
calls.
The show accountingcommand yields the following output for the preceding configuration:
Active Accounted actions on tty1, User username2 Priv 1
Task ID 5, Network Accounting record, 00:00:52 Elapsed
task_id=5 service=ppp protocol=ip address=10.0.0.98

The table below describes the fields contained in the preceding output.
Table 26: show accounting Field Descriptions

Field

Description

Active Accounted actions on

Terminal line or interface name user with which the
user logged in.

User

User’s ID.

Priv

User’s privilege level.

Task ID

Unique identifier for each accounting session.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
172

Configuring Accounting
Configuring AAA Resource Accounting Example

Field

Description

Accounting Record

Type of accounting session.

Elapsed

Length of time (hh:mm:ss) for this session type.

attribute=value

AV pairs associated with this accounting session.

Configuring AAA Resource Accounting Example
The following example shows how to configure the resource failure stop accounting and resource accounting
for start-stop records functions:
!Enable AAA on your network access server.
aaa new-model
!Enable authentication at login and list the AOL string name to use for login authentication.
aaa authentication login AOL group radius local
!Enable authentication for ppp and list the default method to use for PPP authentication.
aaa authentication ppp default group radius local
!Enable authorization for all exec sessions and list the AOL string name to use for
authorization.
aaa authorization exec AOL group radius if-authenticated
!Enable authorization for all network-related service requests and list the default method
to use for all network-related authorizations.
aaa authorization network default group radius if-authenticated
!Enable accounting for all exec sessions and list the default method to use for all start-stop
accounting services.
aaa accounting exec default start-stop group radius
!Enable accounting for all network-related service requests and list the default method to
use for all start-stop accounting services.
aaa accounting network default start-stop group radius
!Enable failure stop accounting.
aaa accounting resource default stop-failure group radius
!Enable resource accounting for start-stop records.
aaa accounting resource default start-stop group radius

Configuring AAA Broadcast Accounting Example
The following example shows how to turn on broadcast accounting using the global aaa accounting command:
aaa group server radius isp
server 10.0.0.1
server 10.0.0.2
aaa group server tacacs+ isp_customer
server 172.0.0.1
aaa accounting network default start-stop broadcast group isp group isp_customer
radius-server host 10.0.0.1
radius-server host 10.0.0.2
radius-server key key1
tacacs-server host 172.0.0.1 key key2

The broadcast keyword causes “start” and “stop” accounting records for network connections to be sent
simultaneously to server 10.0.0.1 in the group isp and to server 172.0.0.1 in the group isp_customer. If server
10.0.0.1 is unavailable, failover to server 10.0.0.2 occurs. If server 172.0.0.1 is unavailable, no failover occurs
because backup servers are not configured for the group isp_customer.

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
173

Configuring Accounting
Configuring per-DNIS AAA Broadcast Accounting Example

Configuring per-DNIS AAA Broadcast Accounting Example
The following example shows how to turn on per-DNIS broadcast accounting using the global aaa dnis map
accounting networkcommand:
aaa group server radius isp
server 10.0.0.1
server 10.0.0.2
aaa group server tacacs+ isp_customer
server 172.0.0.1
aaa dnis map enable
aaa dnis map 7777 accounting network start-stop broadcast group isp group isp_customer
radius-server host 10.0.0.1
radius-server host 10.0.0.2
radius-server key key_1
tacacs-server host 172.0.0.1 key key_2

The broadcast keyword causes “start” and “stop” accounting records for network connection calls having
DNIS number 7777 to be sent simultaneously to server 10.0.0.1 in the group isp and to server 172.0.0.1 in
the group isp_customer. If server 10.0.0.1 is unavailable, failover to server 10.0.0.2 occurs. If server 172.0.0.1
is unavailable, no failover occurs because backup servers are not configured for the group isp_customer.

AAA Session MIB Example
The following example shows how to set up the AAA session MIB feature to disconnect authenticated client
connections for PPP users:
aaa
aaa
aaa
aaa
aaa

new-model
authentication ppp default group radius
authorization network default group radius
accounting network default start-stop group radius
session-mib disconnect

Additional References
The following sections provide references related to the Configuring Accounting feature.
Related Documents
Related Topic

Document Title

Configuring SNMP

Cisco IOS XE Network Management Configuration
Guide

SNMP commands

Cisco IOS Network Management Command Reference

Security commands

Cisco IOS Security Command Reference

Configuring Radius

Configuring RADIUS

Configuring TACACS+

Authentication Authorization and Accounting Configuration Guide Cisco IOS XE Release 3S
174

Configuring Accounting
Additional References

Authentication Authorization And Accounting Configuration Guide Cisco IOS XE Release 3S

Navigation menu

Versions of this User Manual:

Views

Navigation