Wireshark User’s Guide: Version 2.9.0 Guide

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Wireshark User’s Guide

Version 2.9.0

Preface
Foreword
Wireshark is one of those programs that many network managers would love to be able to use, but
they are often prevented from getting what they would like from Wireshark because of the lack of
documentation.
This document is part of an effort by the Wireshark team to improve the usability of Wireshark.
We hope that you find it useful and look forward to your comments.

Who should read this document?
The intended audience of this book is anyone using Wireshark.
This book will explain all the basics and also some of the advanced features that Wireshark
provides. As Wireshark has become a very complex program since the early days, not every feature
of Wireshark may be explained in this book.
This book is not intended to explain network sniffing in general and it will not provide details
about specific network protocols. A lot of useful information regarding these topics can be found at
the Wireshark Wiki at https://wiki.wireshark.org/.
By reading this book, you will learn how to install Wireshark, how to use the basic elements of the
graphical user interface (such as the menu) and what’s behind some of the advanced features that
are not always obvious at first sight. It will hopefully guide you around some common problems
that frequently appear for new (and sometimes even advanced) users of Wireshark.

Acknowledgements
The authors would like to thank the whole Wireshark team for their assistance. In particular, the
authors would like to thank:
• Gerald Combs, for initiating the Wireshark project and funding to do this documentation.
• Guy Harris, for many helpful hints and a great deal of patience in reviewing this document.
• Gilbert Ramirez, for general encouragement and helpful hints along the way.
The authors would also like to thank the following people for their helpful feedback on this
document:
• Pat Eyler, for his suggestions on improving the example on generating a backtrace.
• Martin Regner, for his various suggestions and corrections.

• Graeme Hewson, for a lot of grammatical corrections.
The authors would like to acknowledge those man page and README authors for the Wireshark
project from who sections of this document borrow heavily:
• Scott Renfro from whose mergecap man page mergecap: Merging multiple capture files into one
is derived.
• Ashok Narayanan from whose text2pcap man page text2pcap: Converting ASCII hexdumps to
network captures is derived.

About this document
This book was originally developed by Richard Sharpe with funds provided from the Wireshark
Fund. It was updated by Ed Warnicke and more recently redesigned and updated by Ulf Lamping.
It was originally written in DocBook/XML and converted to AsciiDoc by Gerald Combs.

Where to get the latest copy of this document?
The latest copy of this documentation can always be found at https://www.wireshark.org/docs/.

Providing feedback about this document
Should you have any feedback about this document, please send it to the authors through
wireshark-dev[AT]wireshark.org.

Typographic Conventions
The following table shows the typographic conventions that are used in this guide.
Table 1. Typographic Conventions

Style

Description

Italic

File names, folder names, and extensions C:\Development\wireshark.

Monospace

Commands, flags, and environment
variables

CMake’s -G option.

Bold
Monospace

Commands that should be run by the
user

Run cmake -G Ninja ...

[ Button ]

Dialog and window buttons

Press [ Launch ] to go to the Moon.

Key

Keyboard shortcut

Press Ctrl+Down to move to the next
packet.

Menu item

Select Go › Next Packet to move to the
next packet.

Example

Admonitions
Important and notable items are marked as follows:

WARNING

NOTE

TIP

This is a warning

You should pay attention to a warning, otherwise data loss might occur.

This is a note

A note will point you to common mistakes and things that might not be obvious.
This is a tip

Tips are helpful for your everyday work using Wireshark.

Shell Prompt and Source Code Examples
Bourne shell, normal user

$ # This is a comment
$ git config --global log.abbrevcommit true
Bourne shell, root user

# # This is a comment
# ninja install
Command Prompt (cmd.exe)

>rem This is a comment
>cd C:\Development
PowerShell

PS$># This is a comment
PS$>choco list -l

C Source Code

#include "config.h"
/* This method dissects foos */
static int
dissect_foo_message(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree _U_, void
*data _U_)
{
/* TODO: implement your dissecting code */
return tvb_captured_length(tvb);
}

Introduction
What is Wireshark?
Wireshark is a network packet analyzer. A network packet analyzer will try to capture network
packets and tries to display that packet data as detailed as possible.
You could think of a network packet analyzer as a measuring device used to examine what’s going
on inside a network cable, just like a voltmeter is used by an electrician to examine what’s going on
inside an electric cable (but at a higher level, of course).
In the past, such tools were either very expensive, proprietary, or both. However, with the advent
of Wireshark, all that has changed.
Wireshark is perhaps one of the best open source packet analyzers available today.

Some intended purposes
Here are some examples people use Wireshark for:
• Network administrators use it to troubleshoot network problems
• Network security engineers use it to examine security problems
• QA engineers use it to verify network applications
• Developers use it to debug protocol implementations
• People use it to learn network protocol internals
Beside these examples Wireshark can be helpful in many other situations too.

Features
The following are some of the many features Wireshark provides:
• Available for UNIX and Windows.
• Capture live packet data from a network interface.
• Open files containing packet data captured with tcpdump/WinDump, Wireshark, and a number
of other packet capture programs.
• Import packets from text files containing hex dumps of packet data.
• Display packets with very detailed protocol information.
• Save packet data captured.
• Export some or all packets in a number of capture file formats.
• Filter packets on many criteria.

• Search for packets on many criteria.
• Colorize packet display based on filters.
• Create various statistics.
• …and a lot more!
However, to really appreciate its power you have to start using it.
Wireshark captures packets and lets you examine their contents. shows Wireshark having captured
some packets and waiting for you to examine them.

Figure 1. Wireshark captures packets and lets you examine their contents.

Live capture from many different network media
Wireshark can capture traffic from many different network media types - and despite its name including wireless LAN as well. Which media types are supported, depends on many things like the
operating system you are using. An overview of the supported media types can be found at
https://wiki.wireshark.org/CaptureSetup/NetworkMedia.

Import files from many other capture programs
Wireshark can open packets captured from a large number of other capture programs. For a list of
input formats see Input File Formats.

Export files for many other capture programs
Wireshark can save packets captured in a large number of formats of other capture programs. For
a list of output formats see Output File Formats.

Many protocol dissectors
There are protocol dissectors (or decoders, as they are known in other products) for a great many
protocols: see Protocols and Protocol Fields.

Open Source Software
Wireshark is an open source software project, and is released under the GNU General Public
License (GPL). You can freely use Wireshark on any number of computers you like, without
worrying about license keys or fees or such. In addition, all source code is freely available under
the GPL. Because of that, it is very easy for people to add new protocols to Wireshark, either as
plugins, or built into the source, and they often do!

What Wireshark is not
Here are some things Wireshark does not provide:
• Wireshark isn’t an intrusion detection system. It will not warn you when someone does strange
things on your network that he/she isn’t allowed to do. However, if strange things happen,
Wireshark might help you figure out what is really going on.
• Wireshark will not manipulate things on the network, it will only “measure” things from it.
Wireshark doesn’t send packets on the network or do other active things (except for name
resolutions, but even that can be disabled).

System Requirements
The amount of resources Wireshark needs depends on your environment and on the size of the
capture file you are analyzing. The values below should be fine for small to medium-sized capture
files no more than a few hundred MB. Larger capture files will require more memory and disk
space.
Busy networks mean large captures

NOTE

Working with a busy network can easily produce huge capture files. Capturing on a
gigabit or even 100 megabit network can produce hundreds of megabytes of
capture data in a short time. A fast processor, lots of memory and disk space is
always a good idea.

If Wireshark runs out of memory it will crash. See https://wiki.wireshark.org/KnownBugs/
OutOfMemory for details and workarounds.

Although Wireshark captures packets using a separate process the main interface is singlethreaded and won’t benefit much from multi-core systems.

Microsoft Windows
• The current version of Wireshark should support any version of Windows that is still within its
extended support lifetime. At the time of writing this includes Windows 10, 8, 7, Vista, Server
2016, Server 2012 R2, Server 2012, Server 2008 R2, and Server 2008.
• Any modern 64-bit AMD64/x86-64 or 32-bit x86 processor.
• 400 MB available RAM. Larger capture files require more RAM.
• 300 MB available disk space. Capture files require additional disk space.
• 1024 × 768 (1280 × 1024 or higher recommended) resolution with at least 16-bit color. 8-bit color
should work but user experience will be degraded. Power users will find multiple monitors
useful.
• A supported network card for capturing
◦ Ethernet. Any card supported by Windows should work. See the wiki pages on Ethernet
capture and offloading for issues that may affect your environment.
◦ 802.11. See the Wireshark wiki page. Capturing raw 802.11 information may be difficult
without special equipment.
◦ Other media. See https://wiki.wireshark.org/CaptureSetup/NetworkMedia.
Older versions of Windows which are outside Microsoft’s extended lifecycle support window are no
longer supported. It is often difficult or impossible to support these systems due to circumstances
beyond our control, such as third party libraries on which we depend or due to necessary features
that are only present in newer versions of Windows (such as hardened security or memory
management).
Wireshark 1.12 was the last release branch to support Windows Server 2003. Wireshark 1.10 was
the last branch to officially support Windows XP. See the Wireshark release lifecycle page for more
details.

UNIX / Linux
Wireshark runs on most UNIX and UNIX-like platforms including macOS and Linux. The system
requirements should be comparable to the Windows values listed above.
Binary packages are available for most Unices and Linux distributions including the following
platforms:
• Apple macOS
• Debian GNU/Linux
• FreeBSD

• Gentoo Linux
• HP-UX
• Mandriva Linux
• NetBSD
• OpenPKG
• Red Hat Enterprise/Fedora Linux
• Sun Solaris/i386
• Sun Solaris/SPARC
• Canonical Ubuntu
If a binary package is not available for your platform you can download the source and try to build
it. Please report your experiences to wireshark-dev[AT]wireshark.org.

Where to get Wireshark
You

can

get

the

latest

copy

the

program

from

the

Wireshark

website

https://www.wireshark.org/download.html. The download page should automatically highlight the
appropriate download for your platform and direct you to the nearest mirror. Official Windows
and macOS installers are signed by the Wireshark Foundation.
A new Wireshark version typically becomes available each month or two.
If you want to be notified about new Wireshark releases you should subscribe to the wiresharkannounce mailing list. You will find more details in Mailing Lists.

A brief history of Wireshark
In late 1997 Gerald Combs needed a tool for tracking down network problems and wanted to learn
more about networking so he started writing Ethereal (the original name of the Wireshark project)
as a way to solve both problems.
Ethereal was initially released after several pauses in development in July 1998 as version 0.2.0.
Within days patches, bug reports, and words of encouragement started arriving and Ethereal was
on its way to success.
Not long after that Gilbert Ramirez saw its potential and contributed a low-level dissector to it.
In October, 1998 Guy Harris was looking for something better than tcpview so he started applying
patches and contributing dissectors to Ethereal.
In late 1998 Richard Sharpe, who was giving TCP/IP courses, saw its potential on such courses and
started looking at it to see if it supported the protocols he needed. While it didn’t at that point new
protocols could be easily added. So he started contributing dissectors and contributing patches.
9

The list of people who have contributed to the project has become very long since then, and almost
all of them started with a protocol that they needed that Wireshark or did not already handle. So
they copied an existing dissector and contributed the code back to the team.
In 2006 the project moved house and re-emerged under a new name: Wireshark.
In 2008, after ten years of development, Wireshark finally arrived at version 1.0. This release was
the first deemed complete, with the minimum features implemented. Its release coincided with the
first Wireshark Developer and User Conference, called Sharkfest.
In 2015 Wireshark 2.0 was released, which featured a new user interface.

Development and maintenance of Wireshark
Wireshark was initially developed by Gerald Combs. Ongoing development and maintenance of
Wireshark is handled by the Wireshark team, a loose group of individuals who fix bugs and
provide new functionality.
There have also been a large number of people who have contributed protocol dissectors to
Wireshark, and it is expected that this will continue. You can find a list of the people who have
contributed code to Wireshark by checking the about dialog box of Wireshark, or at the authors
page on the Wireshark web site.
Wireshark is an open source software project, and is released under the GNU General Public
License (GPL) version 2. All source code is freely available under the GPL. You are welcome to
modify Wireshark to suit your own needs, and it would be appreciated if you contribute your
improvements back to the Wireshark team.
You gain three benefits by contributing your improvements back to the community:
1. Other people who find your contributions useful will appreciate them, and you will know that
you have helped people in the same way that the developers of Wireshark have helped people.
2. The developers of Wireshark might improve your changes even more, as there’s always room
for improvement. Or they may implement some advanced things on top of your code, which can
be useful for yourself too.
3. The maintainers and developers of Wireshark will maintain your code as well, fixing it when
API changes or other changes are made, and generally keeping it in tune with what is
happening with Wireshark. So if Wireshark is updated (which is done often), you can get a new
Wireshark version from the website and your changes will already be included without any
effort for you.
The Wireshark source code and binary kits for some platforms are all available on the download
page of the Wireshark website: https://www.wireshark.org/download.html.

Reporting problems and getting help
If you have problems or need help with Wireshark there are several places that may be of interest
to you (well, besides this guide of course).

Website
You will find lots of useful information on the Wireshark homepage at https://www.wireshark.org/.

Wiki
The Wireshark Wiki at https://wiki.wireshark.org/ provides a wide range of information related to
Wireshark and packet capture in general. You will find a lot of information not part of this user’s
guide. For example, there is an explanation how to capture on a switched network, an ongoing
effort to build a protocol reference and a lot more.
And best of all, if you would like to contribute your knowledge on a specific topic (maybe a network
protocol you know well) you can edit the wiki pages by simply using your web browser.

Q&A Site
The Wireshark Q&A site at https://ask.wireshark.org/ offers a resource where questions and
answers come together. You have the option to search what questions were asked before and what
answers were given by people who knew about the issue. Answers are graded, so you can pick out
the best ones easily. If your question hasn’t been discussed before you can post one yourself.

FAQ
The Frequently Asked Questions lists often asked questions and their corresponding answers.
Read the FAQ

NOTE

Before sending any mail to the mailing lists below, be sure to read the FAQ. It will
often answer any questions you might have. This will save yourself and others a lot
of time. Keep in mind that a lot of people are subscribed to the mailing lists.

You will find the FAQ inside Wireshark by clicking the menu item Help/Contents and selecting the
FAQ page in the dialog shown.
An online version is available at the Wireshark website at https://www.wireshark.org/faq.html. You
might prefer this online version, as it’s typically more up to date and the HTML format is easier to
use.

Mailing Lists
There are several mailing lists of specific Wireshark topics available:

wireshark-announce
This mailing list will inform you about new program releases, which usually appear about every
4-8 weeks.
wireshark-users
This list is for users of Wireshark. People post questions about building and using Wireshark,
others (hopefully) provide answers.
wireshark-dev
This list is for Wireshark developers. If you want to start developing a protocol dissector, join
this list.
You can subscribe to each of these lists from the Wireshark web site: https://www.wireshark.org/
lists/. From there, you can choose which mailing list you want to subscribe to by clicking on the
Subscribe/Unsubscribe/Options button under the title of the relevant list. The links to the archives
are included on that page as well.
The lists are archived

TIP

You can search in the list archives to see if someone asked the same question some
time before and maybe already got an answer. That way you don’t have to wait until
someone answers your question.

Reporting Problems
NOTE

Before reporting any problems, please make sure you have installed the latest
version of Wireshark.

When reporting problems with Wireshark please supply the following information:
1. The version number of Wireshark and the dependent libraries linked with it, such as Qt or GLib.
You can obtain this from Wireshark’s about box or the command wireshark -v.
2. Information about the platform you run Wireshark on.
3. A detailed description of your problem.
4. If you get an error/warning message, copy the text of that message (and also a few lines before
and after it, if there are some) so others may find the place where things go wrong. Please don’t
give something like: “I get a warning while doing x” as this won’t give a good idea where to look.
Don’t send large files

NOTE

Do not send large files (> 1 MB) to the mailing lists. Just place a note that further
data is available on request. Large files will only annoy a lot of people on the list
who are not interested in your specific problem. If required you will be asked for
further data by the persons who really can help you.

Don’t send confidential information!

WARNING

If you send capture files to the mailing lists be sure they don’t contain any
sensitive or confidential information like passwords or personally identifiable
information (PII).

Reporting Crashes on UNIX/Linux platforms
When reporting crashes with Wireshark it is helpful if you supply the traceback information along
with the information mentioned in “Reporting Problems”.
You can obtain this traceback information with the following commands on UNIX or Linux (note
the backticks):

$ gdb `whereis wireshark | cut -f2 -d: | cut -d' ' -f2` core >& backtrace.txt
backtrace
^D
If you do not have gdb available, you will have to check out your operating system’s debugger.
Mail backtrace.txt to wireshark-dev[AT]wireshark.org.

Reporting Crashes on Windows platforms
The Windows distributions don’t contain the symbol files (.pdb) because they are very large. You
can download them separately at https://www.wireshark.org/download/win32/all-versions/ and
https://www.wireshark.org/download/win64/all-versions/ .

Building and Installing Wireshark
Introduction
As with all things there must be a beginning and so it is with Wireshark. To use Wireshark you
must first install it. If you are running Windows or macOS you can download an official release at
https://www.wireshark.org/download.html, install it, and skip the rest of this chapter.
If you are running another operating system such as Linux or FreeBSD you might want to install
from source. Several Linux distributions offer Wireshark packages but they commonly ship out-ofdate versions. No other versions of UNIX ship Wireshark so far. For that reason, you will need to
know where to get the latest version of Wireshark and how to install it.
This chapter shows you how to obtain source and binary packages and how to build Wireshark
from source should you choose to do so.
The following are the general steps you would use:
1. Download the relevant package for your needs, e.g. source or binary distribution.
2. Compile the source into a binary if needed. This may involve building and/or installing other
necessary packages.
3. Install the binaries into their final destinations.

Obtaining the source and binary distributions
You can obtain both source and binary distributions from the Wireshark web site:
https://www.wireshark.org/download.html. Select the download link and then select the desired
binary or source package.
Download all required files

NOTE

If you are building Wireshark from source you will In general, unless you have
already downloaded Wireshark before, you will most likely need to download
several source packages if you are building Wireshark from source. This is covered
in more detail below.

Once you have downloaded the relevant files, you can go on to the next step.

Installing Wireshark under Windows
Windows installer names contain the platform and version. For example, Wireshark-win642.9.0.exe installs Wireshark 2.9.0 for 64-bit Windows. The Wireshark installer includes WinPcap
which is required for packet capture.

Simply download the Wireshark installer from https://www.wireshark.org/download.html and
execute it. Official packages are signed by the Wireshark Foundation. You can choose to install
several optional components and select the location of the installed package. The default settings
are recommended for most users.

Installation Components
On the Choose Components page of the installer you can select from the following:
• Wireshark - The network protocol analyzer that we all know and mostly love.
• TShark - A command-line network protocol analyzer. If you haven’t tried it you should.
• Plugins & Extensions - Extras for the Wireshark and TShark dissection engines
◦ Dissector Plugins - Plugins with some extended dissections.
◦ Tree Statistics Plugins - Extended statistics.
◦ Mate - Meta Analysis and Tracing Engine - User configurable extension(s) of the display
filter engine, see MATE for details.
◦ SNMP MIBs - SNMP MIBs for a more detailed SNMP dissection.
• Tools - Additional command line tools to work with capture files
◦ Editcap - Reads a capture file and writes some or all of the packets into another capture file.
◦ Text2Pcap - Reads in an ASCII hex dump and writes the data into a pcap capture file.
◦ Reordercap - Reorders a capture file by timestamp.
◦ Mergecap - Combines multiple saved capture files into a single output file.
◦ Capinfos - Provides information on capture files.
◦ Rawshark - Raw packet filter.
• User’s Guide - Local installation of the User’s Guide. The Help buttons on most dialogs will
require an internet connection to show help pages if the User’s Guide is not installed locally.

Additional Tasks
• Start Menu Shortcuts - Add some start menu shortcuts.
• Desktop Icon - Add a Wireshark icon to the desktop.
• Quick Launch Icon - add a Wireshark icon to the Explorer quick launch toolbar.
• Associate file extensions to Wireshark - Associate standard network trace files to Wireshark.

Install Location
By

default

Wireshark

installs

into

%ProgramFiles%\Wireshark

32-bit

Windows

and

%ProgramFiles64%\Wireshark on 64-bit Windows. This expands to C:\Program Files\Wireshark on
most systems.

Installing WinPcap
The Wireshark installer contains the latest WinPcap installer.
If you don’t have WinPcap installed you won’t be able to capture live network traffic but you will
still be able to open saved capture files. By default the latest version of WinPcap will be installed. If
you don’t wish to do this or if you wish to reinstall WinPcap you can check the Install WinPcap box
as needed.
For more information about WinPcap see https://www.winpcap.org/ and https://wiki.wireshark.org/
WinPcap.

Windows installer command line options
For special cases, there are some command line parameters available:
• /S runs the installer or uninstaller silently with default values. The silent installer will not
install WinPCap.
• /desktopicon installation of the desktop icon, =yes - force installation, =no - don’t install,
otherwise use default settings. This option can be useful for a silent installer.
• /quicklaunchicon installation of the quick launch icon, =yes - force installation, =no - don’t install,
otherwise use default settings.
• /D sets the default installation directory ($INSTDIR), overriding InstallDir and InstallDirRegKey.
It must be the last parameter used in the command line and must not contain any quotes even if
the path contains spaces.
• /NCRC disables the CRC check. We recommend against using this flag.
Example:

> Wireshark-win64-wireshark-2.0.5.exe /NCRC /S /desktopicon=yes /quicklaunchicon=no
/D=C:\Program Files\Foo
Running the installer without any parameters shows the normal interactive installer.

Manual WinPcap Installation
As mentioned above, the Wireshark installer takes care of installing WinPcap. The following is only
necessary if you want to use a different version than the one included in the Wireshark installer,
e.g. because a new WinPcap version was released.
Additional WinPcap versions (including newer alpha or beta releases) can be downloaded from the
main WinPcap site at https://www.winpcap.org/. The Installer for Windows supports modern
Windows operating systems.

Update Wireshark
By default the offical Windows package will check for new versions and notify you when they are
available. If you have the Check for updates preference disabled or if you run Wireshark in an
isolated environment you should subcribe to the wireshark-announce mailing list. See Mailing Lists
for details on subscribing to this list.
New versions of Wireshark are usually released every four to six weeks. Updating Wireshark is
done the same way as installing it. Simply download and start the installer exe. A reboot is usually
not required and all your personal settings remain unchanged.

Update WinPcap
New versions of WinPcap are less frequently available. You will find WinPcap update instructions
the WinPcap web site at https://www.winpcap.org/. You may have to reboot your machine after
installing a new WinPcap version.

Uninstall Wireshark
You can uninstall Wireshark using the Programs and Features control panel. Select the “Wireshark”
entry to start the uninstallation procedure.
The Wireshark uninstaller provides several options for removal. The default is to remove the core
components but keep your personal settings and WinPcap. WinPcap is left installed by default in
case other programs need it.

Uninstall WinPcap
You can uninstall WinPcap independently of Wireshark using the WinPcap entry in the Programs
and Features control panel. Remember that if you uninstall WinPcap you won’t be able to capture
anything with Wireshark.

Installing Wireshark under macOS
The official macOS packages are distributed as disk images (.dmg) containing the application
installer. To install Wireshark simply open the disk image and run the enclosed installer.
The installer package includes Wireshark, its related command line utilities, and a launch daemon
that adjusts capture permissions at system startup. See the included Read me first file for more
details.

Building Wireshark from source under UNIX
Building Wireshark requires the proper build environment including a compiler and many
supporting libraries. See the Developer’s Guide at https://www.wireshark.org/docs/ for more

information.
Use the following general steps to build Wireshark from source under UNIX or Linux:
1. Unpack the source from its compressed tar file. If you are using Linux or your version of UNIX
uses GNU tar you can use the following command:

$ tar xaf wireshark-2.9.0.tar.xz
In other cases you will have to use the following commands:

$ xz -d wireshark-2.9.0.tar.xz
$ tar xf wireshark-2.9.0.tar
2. Create a directory to build Wireshark in and change to it.

$ mkdir build
$ cd build
3. Configure your source so it will build correctly for your version of UNIX. You can do this with
the following command:

$ cmake ../wireshark-2.9.0
If this step fails you will have to look into the logs and rectify the problems, then rerun cmake.
Troubleshooting hints are provided in Troubleshooting during the build and install on Unix.
4. Build the sources.

$ make
Once you have build Wireshark with make above, you should be able to run it by entering
run/wireshark.
5. Install the software in its final destination.

$ make install

Once you have installed Wireshark with make install above, you should be able to run it by
entering wireshark.

Installing the binaries under UNIX
In general installing the binary under your version of UNIX will be specific to the installation
methods used with your version of UNIX. For example, under AIX, you would use smit to install the
Wireshark binary package, while under Tru64 UNIX (formerly Digital UNIX) you would use setld.

Installing from RPMs under Red Hat and alike
Building RPMs from Wireshark’s source code results in several packages (most distributions follow
the same system):
• The wireshark package contains the core Wireshark libraries and command-line tools.
• The wireshark or wireshark-qt package contains the Qt-based GUI.
Many distributions use yum or a similar package management tool to make installation of software
(including its dependencies) easier. If your distribution uses yum, use the following command to
install Wireshark together with the Qt GUI:

yum install wireshark wireshark-qt
If you’ve built your own RPMs from the Wireshark sources you can install them by running, for
example:

rpm -ivh wireshark-2.0.0-1.x86_64.rpm wireshark-qt-2.0.0-1.x86_64.rpm
If the above command fails because of missing dependencies, install the dependencies first, and
then retry the step above.

Installing from debs under Debian, Ubuntu and other Debian derivatives
If you can just install from the repository then use

$ aptitude install wireshark
Aptitude should take care of all of the dependency issues for you.
Use the following command to install downloaded Wireshark debs under Debian:

$ dpkg -i wireshark-common_2.0.5.0-1_i386.deb wireshark_wireshark-2.0.5.0-1_i386.deb
dpkg doesn’t take care of all dependencies, but reports what’s missing.

Capturing requires privileges

NOTE

By installing Wireshark packages non-root users won’t gain rights automatically to
capture packets. To allow non-root users to capture packets follow the procedure
described in /usr/share/doc/wireshark-common/README.Debian

Installing from portage under Gentoo Linux
Use the following command to install Wireshark under Gentoo Linux with all of the extra features:

$ USE="c-ares ipv6 snmp ssl kerberos threads selinux" emerge wireshark

Installing from packages under FreeBSD
Use the following command to install Wireshark under FreeBSD:

$ pkg_add -r wireshark
pkg_add should take care of all of the dependency issues for you.

Troubleshooting during the build and install on Unix
A number of errors can occur during the build and installation process. Some hints on solving these
are provided here.
If the cmake stage fails you will need to find out why. You can check the file CMakeOutput.log and
CMakeError.log in the build directory to find out what failed. The last few lines of this file should
help in determining the problem.
The standard problems are that you do not have a required development package on your system
or that the development package isn’t new enough. Note that installing a library package isn’t
enough. You need to install its development package as well. cmake will also fail if you do not have
libpcap (at least the required include files) on your system.
If you cannot determine what the problems are, send an email to the wireshark-dev mailing list
explaining your problem. Include the output from cmake and anything else you think is relevant
such as a trace of the make stage.

Building from source under Windows
We strongly recommended that you use the binary installer for Windows unless you want to start
developing Wireshark on the Windows platform.

For further information how to build Wireshark for Windows from the sources see the Developer’s
Guide at https://www.wireshark.org/docs/.
You may also want to have a look at the Development Wiki (https://wiki.wireshark.org/
Development) for the latest available development documentation.

User Interface
Introduction
By now you have installed Wireshark and are most likely keen to get started capturing your first
packets. In the next chapters we will explore:
• How the Wireshark user interface works
• How to capture packets in Wireshark
• How to view packets in Wireshark
• How to filter packets in Wireshark
• … and many other things!

Start Wireshark
You can start Wireshark from your shell or window manager.
Power user tip

TIP

When starting Wireshark it’s possible to specify optional settings using the command
line. See Start Wireshark from the command line for details.

In the following chapters a lot of screenshots from Wireshark will be shown. As Wireshark runs on
many different platforms with many different window managers, different styles applied and there
are different versions of the underlying GUI toolkit used, your screen might look different from the
provided screenshots. But as there are no real differences in functionality these screenshots should
still be well understandable.

The Main window
Let’s look at Wireshark’s user interface. The Main window shows Wireshark as you would usually
see it after some packets are captured or loaded (how to do this will be described later).

Figure 2. The Main window

Wireshark’s main window consists of parts that are commonly known from many other GUI
programs.
1. The menu (see The Menu) is used to start actions.
2. The main toolbar (see The “Main” Toolbar) provides quick access to frequently used items from
the menu.
3. The filter toolbar (see The “Filter” Toolbar) provides a way to directly manipulate the currently
used display filter (see Filtering packets while viewing).
4. The packet list pane (see The “Packet List” Pane) displays a summary of each packet captured. By
clicking on packets in this pane you control what is displayed in the other two panes.
5. The packet details pane (see The “Packet Details” Pane) displays the packet selected in the packet
list pane in more detail.
6. The packet bytes pane (see The “Packet Bytes” Pane) displays the data from the packet selected in
the packet list pane, and highlights the field selected in the packet details pane.
7. The statusbar (see The Statusbar) shows some detailed information about the current program
state and the captured data.
TIP

The layout of the main window can be customized by changing preference settings.
See Preferences for details!

Main Window Navigation
Packet list and detail navigation can be done entirely from the keyboard. Keyboard Navigation
shows a list of keystrokes that will let you quickly move around a capture file. See Go menu items
for additional navigation keystrokes.
Table 2. Keyboard Navigation

Accelerator

Description

Tab or Shift+Tab

Move between screen elements, e.g. from the toolbars to the packet list to
the packet detail.

↓

Move to the next packet or detail item.

↑

Move to the previous packet or detail item.

Ctrl+↓ or F8

Move to the next packet, even if the packet list isn’t focused.

Ctrl+↑ or F7

Move to the previous packet, even if the packet list isn’t focused.

Ctrl+.

Move to the next packet of the conversation (TCP, UDP or IP).

Ctrl+,

Move to the previous packet of the conversation (TCP, UDP or IP).

Alt+→ or Option+→
(macOS)

Move to the next packet in the selection history.

Alt+← or Option+←
(macOS)

Move to the previous packet in the selection history.

←

In the packet detail, closes the selected tree item. If it’s already closed,
jumps to the parent node.

→

In the packet detail, opens the selected tree item.

Shift+→

In the packet detail, opens the selected tree item and all of its subtrees.

Ctrl+→

In the packet detail, opens all tree items.

Ctrl+←

In the packet detail, closes all tree items.

Backspace

In the packet detail, jumps to the parent node.

Return or Enter

In the packet detail, toggles the selected tree item.

Help › About Wireshark › Keyboard Shortcuts will show a list of all shortcuts in the main
window. Additionally, typing anywhere in the main window will start filling in a display filter.

The Menu
Wireshark’s main menu is located either at the top of the main window (Windows, Linux) or at the
top of your main screen (macOS). An example is shown in The Menu.
Some menu items will be disabled (greyed out) if the corresponding feature isn’t
NOTE

available. For example, you cannot save a capture file if you haven’t captured or
loaded any packets.

Figure 3. The Menu

The main menu contains the following items:
File
This menu contains items to open and merge capture files, save, print, or export capture files in
whole or in part, and to quit the Wireshark application. See The “File” menu.
Edit
This menu contains items to find a packet, time reference or mark one or more packets, handle
configuration profiles, and set your preferences; (cut, copy, and paste are not presently
implemented). See The “Edit” Menu.
View
This menu controls the display of the captured data, including colorization of packets, zooming
the font, showing a packet in a separate window, expanding and collapsing trees in packet
details, …. See The “View” Menu.
Go
This menu contains items to go to a specific packet. See The “Go” Menu.
Capture
This menu allows you to start and stop captures and to edit capture filters. See The “Capture”
menu.
Analyze
This menu contains items to manipulate display filters, enable or disable the dissection of
protocols, configure user specified decodes and follow a TCP stream. See The “Analyze” Menu.
Statistics
This menu contains items to display various statistic windows, including a summary of the
packets that have been captured, display protocol hierarchy statistics and much more. See The
“Statistics” Menu.
Telephony
This menu contains items to display various telephony related statistic windows, including a
media analysis, flow diagrams, display protocol hierarchy statistics and much more. See The
“Telephony” Menu.
Wireless
The items in this menu show Bluetooth and IEEE 802.11 wireless statistics.
Tools
This menu contains various tools available in Wireshark, such as creating Firewall ACL Rules.

See The “Tools” Menu.
Help
This menu contains items to help the user, e.g. access to some basic help, manual pages of the
various command line tools, online access to some of the webpages, and the usual about dialog.
See The “Help” Menu.
Each of these menu items is described in more detail in the sections that follow.
Shortcuts make life easier

TIP

Most common menu items have keyboard shortcuts. For example, you can press the
Control (or Strg in German) and the K keys together to open the “Capture Options”
dialog.

The “File” menu
The Wireshark file menu contains the fields shown in File menu items.

Figure 4. The “File” Menu
Table 3. File menu items

Menu Item

Accelerator

Description

Open…

Ctrl+O

This shows the file open dialog box that allows
you to load a capture file for viewing. It is
discussed in more detail in The “Open Capture
File” dialog box.

Open Recent

This lets you open recently opened capture files.
Clicking on one of the submenu items will open
the corresponding capture file directly.

Merge…

This menu item lets you merge a capture file
into the currently loaded one. It is discussed in
more detail in Merging capture files.

Import from Hex Dump…

This menu item brings up the import file dialog
box that allows you to import a text file
containing a hex dump into a new temporary
capture. It is discussed in more detail in Import
hex dump.

Ctrl+W

This menu item closes the current capture. If
you haven’t saved the capture, you will be asked
to do so first (this can be disabled by a
preference setting).

Save

Ctrl+S

This menu item saves the current capture. If you
have not set a default capture file name
(perhaps with the -w option),
Wireshark pops up the Save Capture File As
dialog box (which is discussed further in The
“Save Capture File As” dialog box).
If you have already saved the current capture,
this menu item will be greyed out.
You cannot save a live capture while the capture
is in progress. You must stop the capture in
order to save.

Save As…

File Set › List Files

Shift+Ctrl+S

This menu item allows you to save the current
capture file to whatever file you would like. It
pops up the Save Capture File As dialog box
(which is discussed further in The “Save Capture
File As” dialog box).
This menu item allows you to show a list of files
in a file set. It pops up the Wireshark List File Set
dialog box (which is discussed further in File
Sets).

Menu Item

Accelerator

Description

File Set › Next File

If the currently loaded file is part of a file set,
jump to the next file in the set. If it isn’t part of a
file set or just the last file in that set, this item is
greyed out.

File Set › Previous File

If the currently loaded file is part of a file set,
jump to the previous file in the set. If it isn’t part
of a file set or just the first file in that set, this
item is greyed out.

Export Specified Packets…

This menu item allows you to export all (or
some) of the packets in the capture file to file. It
pops up the Wireshark Export dialog box (which
is discussed further in Exporting data).

Export Packet
Dissections…

Ctrl+H

Export Objects

These menu items allow you to export the
currently selected bytes in the packet bytes pane
to a text file file in a number of formats
including plain, CSV, and XML. It is discussed
further in The “Export selected packet bytes”
dialog box.
These menu items allow you to export captured
DICOM, HTTP, IMF, SMB, or TFTP objects into
local files. It pops up a corresponding object list
(which is discussed further in The “Export
Objects” dialog box)

Print…

Ctrl+P

This menu item allows you to print all (or some)
of the packets in the capture file. It pops up the
Wireshark Print dialog box (which is discussed
further in Printing packets).

Quit

Ctrl+Q

This menu item allows you to quit from
Wireshark. Wireshark will ask to save your
capture file if you haven’t previously saved it
(this can be disabled by a preference setting).

The “Edit” Menu
The Wireshark Edit menu contains the fields shown in Edit menu items.

Figure 5. The “Edit” Menu
Table 4. Edit menu items

Menu Item

Accelerator

Copy

Description
These menu items will copy the packet list,
packet detail, or properties of the currently
selected packet to the clipboard.

Find Packet…

Ctrl+F

This menu item brings up a toolbar that allows
you to find a packet by many criteria. There is
further information on finding packets in
Finding packets.

Find Next

Ctrl+N

This menu item tries to find the next packet
matching the settings from “Find Packet…”.

Find Previous

Ctrl+B

This menu item tries to find the previous packet
matching the settings from “Find Packet…”.

Mark/Unmark Packet

Ctrl+M

This menu item marks the currently selected
packet. See Marking packets for details.

Mark All Displayed Packets Shift+Ctrl+M

This menu item marks all displayed packets.

Unmark All Displayed
Packets

Ctrl+Alt+M

This menu item unmarks all displayed packets.

Next Mark

Shift+Alt+N

Find the next marked packet.

Previous Mark

Shift+Alt+B

Find the previous marked packet.

Menu Item

Accelerator

Description

Ignore/Unignore Packet

Ctrl+D

This menu item marks the currently selected
packet as ignored. See Ignoring packets for
details.

Ignore All Displayed

Shift+Ctrl+D

This menu item marks all displayed packets as
ignored.

Unignore All Displayed

Ctrl+Alt+D

This menu item unmarks all ignored packets.

Set/Unset Time Reference

Ctrl+T

This menu item set a time reference on the
currently selected packet. See Packet time
referencing for more information about the time
referenced packets.

Unset All Time References Ctrl+Alt+T

This menu item removes all time references on
the packets.

Next Time Reference

Ctrl+Alt+N

This menu item tries to find the next time
referenced packet.

Previous Time Reference

Ctrl+Alt+B

This menu item tries to find the previous time
referenced packet.

Time Shift

Ctrl+Shift+T

This will show the Time Shift dialog, which
allows you to adjust the timestamps of some or
all packets.

Packet Comment…

This will let you add a comment to a single
packet. Note that the ability to save packet
comments depends on your file format. E.g.
pcapng supports comments, pcap does not.

Capture Comment…

This will let you add a capture comment. Note
that the ability to save capture comments
depends on your file format. E.g. pcapng
supports comments, pcap does not.

Configuration Profiles…

Shift+Ctrl+A

This menu item brings up a dialog box for
handling configuration profiles. More detail is
provided in Configuration Profiles.

Preferences…

Shift+Ctrl+P or
Cmd+, (macOS)

This menu item brings up a dialog box that
allows you to set preferences for many
parameters that control Wireshark. You can also
save your preferences so Wireshark will use
them the next time you start it. More detail is
provided in Preferences.

The “View” Menu
The Wireshark View menu contains the fields shown in View menu items.

Figure 6. The “View” Menu
Table 5. View menu items

Menu Item

Accelerator

Description

Main Toolbar

This menu item hides or shows the main toolbar,
see The “Main” Toolbar.

Filter Toolbar

This menu item hides or shows the filter toolbar,
see The “Filter” Toolbar.

Wireless Toolbar

This menu item hides or shows the wireless
toolbar. May not be present on some platforms.

Statusbar

This menu item hides or shows the statusbar,
see The Statusbar.

Packet List

This menu item hides or shows the packet list
pane, see The “Packet List” Pane.

Packet Details

This menu item hides or shows the packet
details pane, see The “Packet Details” Pane.

Packet Bytes

This menu item hides or shows the packet bytes
pane, see The “Packet Bytes” Pane.

Menu Item
Time Display Format ›
Date and Time of Day:
1970-01-01 01:02:03.123456

Accelerator

Description
Selecting this tells Wireshark to display the time
stamps in date and time of day format, see Time
display formats and time references.
The fields “Time of Day”, “Date and Time of
Day”, “Seconds Since Beginning of Capture”,
“Seconds Since Previous Captured Packet” and
“Seconds Since Previous Displayed Packet” are
mutually exclusive.

Time Display Format ›
Time of Day:
01:02:03.123456

Selecting this tells Wireshark to display time
stamps in time of day format, see Time display
formats and time references.

Time Display Format ›
Seconds Since Epoch (197001-01): 1234567890.123456

Selecting this tells Wireshark to display time
stamps in seconds since 1970-01-01 00:00:00, see
Time display formats and time references.

Time Display Format ›
Seconds Since Beginning of
Capture: 123.123456

Selecting this tells Wireshark to display time
stamps in seconds since beginning of capture
format, see Time display formats and time
references.

Time Display Format ›
Seconds Since Previous
Captured Packet: 1.123456

Selecting this tells Wireshark to display time
stamps in seconds since previous captured
packet format, see Time display formats and
time references.

Time Display Format ›
Seconds Since Previous
Displayed Packet: 1.123456

Selecting this tells Wireshark to display time
stamps in seconds since previous displayed
packet format, see Time display formats and
time references.

Time Display Format ›
Automatic (File Format
Precision)

Selecting this tells Wireshark to display time
stamps with the precision given by the capture
file format used, see Time display formats and
time references.
The fields “Automatic”, “Seconds” and “…
seconds” are mutually exclusive.

Time Display Format ›
Seconds: 0

Selecting this tells Wireshark to display time
stamps with a precision of one second, see Time
display formats and time references.

Time Display Format › …
seconds: 0….

Selecting this tells Wireshark to display time
stamps with a precision of one second,
decisecond, centisecond, millisecond,
microsecond or nanosecond, see Time display
formats and time references.

Menu Item

Accelerator

Description

Time Display Format ›
Display Seconds with
hours and minutes

Selecting this tells Wireshark to display time
stamps in seconds, with hours and minutes.

Name Resolution › Resolve
Name

This item allows you to trigger a name resolve of
the current packet only, see Name Resolution.

Name Resolution › Enable
for MAC Layer

This item allows you to control whether or not
Wireshark translates MAC addresses into names,
see Name Resolution.

Name Resolution › Enable
for Network Layer

This item allows you to control whether or not
Wireshark translates network addresses into
names, see Name Resolution.

Name Resolution › Enable
for Transport Layer

This item allows you to control whether or not
Wireshark translates transport addresses into
names, see Name Resolution.

Colorize Packet List

This item allows you to control whether or not
Wireshark should colorize the packet list.
Enabling colorization will slow down the display
of new packets while capturing / loading capture
files.

Auto Scroll in Live Capture

This item allows you to specify that Wireshark
should scroll the packet list pane as new packets
come in, so you are always looking at the last
packet. If you do not specify this, Wireshark
simply adds new packets onto the end of the list,
but does not scroll the packet list pane.

Zoom In

Ctrl++

Zoom into the packet data (increase the font
size).

Zoom Out

Ctrl+-

Zoom out of the packet data (decrease the font
size).

Normal Size

Ctrl+=

Set zoom level back to 100% (set font size back to
normal).

Resize All Columns

Shift+Ctrl+R

Resize all column widths so the content will fit
into it.
Resizing may take a significant amount of time,
especially if a large capture file is loaded.

Displayed Columns

Expand Subtrees

This menu items folds out with a list of all
configured columns. These columns can now be
shown or hidden in the packet list.
Shift+→

This menu item expands the currently selected
subtree in the packet details tree.

Menu Item

Accelerator

Description

Collapse Subtrees

Shift+←

This menu item collapses the currently selected
subtree in the packet details tree.

Expand All

Ctrl+→

Wireshark keeps a list of all the protocol
subtrees that are expanded, and uses it to
ensure that the correct subtrees are expanded
when you display a packet. This menu item
expands all subtrees in all packets in the
capture.

Collapse All

Ctrl+←

This menu item collapses the tree view of all
packets in the capture list.

Colorize Conversation

This menu item brings up a submenu that allows
you to color packets in the packet list pane based
on the addresses of the currently selected
packet. This makes it easy to distinguish packets
belonging to different conversations. Packet
colorization.

Colorize Conversation ›
Color 1-10

These menu items enable one of the ten
temporary color filters based on the currently
selected conversation.

Colorize Conversation ›
Reset coloring

This menu item clears all temporary coloring
rules.

Colorize Conversation ›
New Coloring Rule…

This menu item opens a dialog window in which
a new permanent coloring rule can be created
based on the currently selected conversation.

Coloring Rules…

This menu item brings up a dialog box that
allows you to color packets in the packet list
pane according to filter expressions you choose.
It can be very useful for spotting certain types of
packets, see Packet colorization.

Show Packet in New
Window

This menu item brings up the selected packet in
a separate window. The separate window shows
only the tree view and byte view panes.

Reload

Ctrl+R

This menu item allows you to reload the current
capture file.

The “Go” Menu
The Wireshark Go menu contains the fields shown in Go menu items.

Figure 7. The “Go” Menu
Table 6. Go menu items

Menu Item

Accelerator

Description

Back

Alt+←

Jump to the recently visited packet in the packet
history, much like the page history in a web
browser.

Forward

Alt+→

Jump to the next visited packet in the packet
history, much like the page history in a web
browser.

Go to Packet…

Ctrl+G

Bring up a window frame that allows you to
specify a packet number, and then goes to that
packet. See Go to a specific packet for details.

Go to Corresponding
Packet

Go to the corresponding packet of the currently
selected protocol field. If the selected field
doesn’t correspond to a packet, this item is
greyed out.

Previous Packet

Ctrl+↑

Move to the previous packet in the list. This can
be used to move to the previous packet even if
the packet list doesn’t have keyboard focus.

Next Packet

Ctrl+↓

Move to the next packet in the list. This can be
used to move to the previous packet even if the
packet list doesn’t have keyboard focus.

Menu Item

Accelerator

Description

First Packet

Ctrl+Home

Jump to the first packet of the capture file.

Last Packet

Ctrl+End

Jump to the last packet of the capture file.

Previous Packet In
Conversation

Ctrl+,

Move to the previous packet in the current
conversation. This can be used to move to the
previous packet even if the packet list doesn’t
have keyboard focus.

Next Packet In
Conversation

Ctrl+.

Move to the next packet in the current
conversation. This can be used to move to the
previous packet even if the packet list doesn’t
have keyboard focus.

The “Capture” menu
The Wireshark Capture menu contains the fields shown in Capture menu items.

Figure 8. The “Capture” Menu
Table 7. Capture menu items

Menu Item

Accelerator

Description

Interfaces…

Ctrl+I

This menu item brings up a dialog box that
shows what’s going on at the network interfaces
Wireshark knows of, see The “Capture
Interfaces” dialog box) .

Options…

Ctrl+K

This menu item brings up the Capture Options
dialog box (discussed further in The “Capture
Options” dialog box) and allows you to start
capturing packets.

Start

Ctrl+E

Immediately start capturing packets with the
same settings than the last time.

Stop

Ctrl+E

This menu item stops the currently running
capture, see Stop the running capture) .

Restart

Ctrl+R

This menu item stops the currently running
capture and starts again with the same options,
this is just for convenience.

Capture Filters…

This menu item brings up a dialog box that
allows you to create and edit capture filters. You
can name filters, and you can save them for
future use. More detail on this subject is
provided in Defining and saving filters

The “Analyze” Menu
The Wireshark Analyze menu contains the fields shown in Analyze menu items.

Figure 9. The “Analyze” Menu
Table 8. Analyze menu items

Menu Item

Accelerator

Description

Display Filters…

This menu item brings up a dialog box that
allows you to create and edit display filters. You
can name filters, and you can save them for
future use. More detail on this subject is
provided in Defining and saving filters

Display Filter Macros…

This menu item brings up a dialog box that
allows you to create and edit display filter
macros. You can name filter macros, and you
can save them for future use. More detail on this
subject is provided in Defining and saving filter
macros

Apply as Column

This menu item adds the selected protocol item
in the packet details pane as a column to the
packet list.

Apply as Filter › …

These menu items will change the current
display filter and apply the changed filter
immediately. Depending on the chosen menu
item, the current display filter string will be
replaced or appended to by the selected protocol
field in the packet details pane.

Menu Item

Accelerator

These menu items will change the current
display filter but won’t apply the changed filter.
Depending on the chosen menu item, the
current display filter string will be replaced or
appended to by the selected protocol field in the
packet details pane.

Prepare a Filter › …

Enabled Protocols…

Description

Shift+Ctrl+E

This menu item allows the user to enable/disable
protocol dissectors, see The “Enabled Protocols”
dialog box

Decode As…

This menu item allows the user to force
Wireshark to decode certain packets as a
particular protocol, see User Specified Decodes

User Specified Decodes…

This menu item allows the user to force
Wireshark to decode certain packets as a
particular protocol, see Show User Specified
Decodes

Follow › TCP Stream

This menu item brings up a separate window
and displays all the TCP segments captured that
are on the same TCP connection as a selected
packet, see Following Protocol Streams

Follow › UDP Stream

Same functionality as “Follow TCP Stream” but
for UDP streams.

Follow › SSL Stream

Same functionality as “Follow TCP Stream” but
for SSL streams. See the wiki page on SSL for
instructions on providing SSL keys.

Follow › HTTP Stream

Same functionality as “Follow TCP Stream” but
for HTTP streams.

Expert Info

Open a dialog showing some expert information
about the captured packets. The amount of
information will depend on the protocol and
varies from very detailed to non-existent. XXX add a new section about this and link from here

Conversation Filter › …

In this menu you will find conversation filter for
various protocols.

The “Statistics” Menu
The Wireshark Statistics menu contains the fields shown in Statistics menu items.

Figure 10. The “Statistics” Menu

All menu items will bring up a new window showing specific statistical information.
Table 9. Statistics menu items

Menu Item

Accelerator

Description

Capture File Properties

Show information about the capture file, see The
“Capture File Properties” Window.

Resolved Addresses

See Resolved Addresses

Protocol Hierarchy

Display a hierarchical tree of protocol statistics,
see The “Protocol Hierarchy” Window.

Conversations

Display a list of conversations (traffic between
two endpoints), see The “Conversations”
Window.

Endpoints

Display a list of endpoints (traffic to/from an
address), see The “Endpoints” Window.

Packet Lengths

See Packet Lengths

IO Graphs

Display user specified graphs (e.g. the number of
packets in the course of time), see The “I/O
Graph” Window.

Service Response Time

Display the time between a request and the
corresponding response, see Service Response
Time.

Menu Item

Accelerator

Description

DHCP (BOOTP)

See DHCP (BOOTP) Statistics

ONC-RPC Programs

See ONC-RPC Programs

29West

See 29West

ANCP

See ANCP

BACnet

See BACnet

Collectd

See Collectd

DNS

See DNS

Flow Graph

See Flow Graph

HART-IP

See HART-IP

HPFEEDS

See HPFEEDS

HTTP

HTTP request/response statistics, see HTTP
Statistics

HTTP2

See HTTP2

Sametime

See Sametime

TCP Stream Graphs

See TCP Stream Graphs

UDP Multicast Streams

See UDP Multicast Graphs

See F5

IPv4 Statistics

See IPv4 Statistics

IPv6 Statistics

See IPv6 Statistics

The “Telephony” Menu
The Wireshark Telephony menu contains the fields shown in Telephony menu items.

Figure 11. The “Telephony” Menu

All menu items will bring up a new window showing specific telephony related statistical
information.
Table 10. Telephony menu items

Menu Item

Accelerator

Description

VoIP Calls…

See VoIP Calls

menu:[ANSI]

See ANSI

menu:[GSM]

See GSM

menu:[IAX2 Stream
Analysis]

See IAX2 Stream Analysis

menu:[ISUP Messages]

See ISUP Messages

menu:[LTE]

See LTE

menu:[MTP3]

See MTP3

menu:[Osmux]

See Osmux

menu:[RTP]

See RTP Analysis

menu:[RTSP]

See RTSP

menu:[SCTP]

See SCTP

menu:[SMPP Operations]

See SMPP Operations

menu:[UCP Messages]

See UCP Messages

Menu Item

Accelerator

Description

menu:[H.225]

See H.225

menu:[SIP Flows]

See SIP Flows

menu:[SIP Statistics]

See SIP Statistics

menu:[WAP-WSP Packet
Counter]

See WAP-WSP Packet Counter

The “Tools” Menu
The Wireshark Tools menu contains the fields shown in Tools menu items.

Figure 12. The “Tools” Menu
Table 11. Tools menu items

Menu Item

Accelerator

Firewall ACL Rules

Description
This allows you to create command-line ACL
rules for many different firewall products,
including Cisco IOS, Linux Netfilter (iptables),
OpenBSD pf and Windows Firewall (via netsh).
Rules for MAC addresses, IPv4 addresses, TCP
and UDP ports, and IPv4+port combinations are
supported.
It is assumed that the rules will be applied to an
outside interface.

Lua

These options allow you to work with the Lua
interpreter optionally build into Wireshark. See
the “Lua Support in Wireshark” in the
Wireshark Developer’s Guide.

The “Internals” Menu
The Wireshark Internals menu contains the fields shown in Internals menu items.

Figure 13. The “Internals” Menu
Table 12. Internals menu items

Menu Item

Accelerator

Description

Dissector tables

This menu item brings up a dialog box showing
the tables with subdissector relationships.

Supported Protocols
(slow!)

This menu item brings up a dialog box showing
the supported protocols and protocol fields.

The “Help” Menu
The Wireshark Help menu contains the fields shown in Help menu items.

Figure 14. The “Help” Menu
Table 13. Help menu items

Menu Item

Accelerator

Description

Contents

This menu item brings up a basic help system.

Manual Pages › …

This menu item starts a Web browser showing
one of the locally installed html manual pages.

Website

This menu item starts a Web browser showing
the webpage from: https://www.wireshark.org/.

FAQs

This menu item starts a Web browser showing
various FAQs.

Menu Item

Accelerator

Description

Downloads

This menu item starts a Web browser showing
the downloads from: https://www.wireshark.org/
download.html.

Wiki

This menu item starts a Web browser showing
the front page from: https://wiki.wireshark.org/.

Sample Captures

This menu item starts a Web browser showing
the sample captures from:
https://wiki.wireshark.org/SampleCaptures.

About Wireshark

This menu item brings up an information
window that provides various detailed
information items on Wireshark, such as how
it’s built, the plugins loaded, the used folders, …

Opening a Web browser might be unsupported in your version of Wireshark. If this
is the case the corresponding menu items will be hidden.
NOTE

If calling a Web browser fails on your machine, nothing happens, or the browser
starts but no page is shown, have a look at the web browser setting in the
preferences dialog.

The “Main” Toolbar
The main toolbar provides quick access to frequently used items from the menu. This toolbar
cannot be customized by the user, but it can be hidden using the View menu, if the space on the
screen is needed to show even more packet data.
As in the menu, only the items useful in the current program state will be available. The others will
be greyed out (e.g. you cannot save a capture file if you haven’t loaded one).

Figure 15. The “Main” toolbar
Table 14. Main toolbar items

Toolbar
Icon

Toolbar Item

Menu Item

Description

[ Interfaces… ]

Capture ›
Interfaces…

This item brings up the Capture Interfaces
List dialog box (discussed further in Start
Capturing).

[ Options… ]

Capture › Options… This item brings up the Capture Options
dialog box (discussed further in Start
Capturing) and allows you to start
capturing packets.

Toolbar
Icon

Toolbar Item

Menu Item

Description

[ Start ]

Capture › Start

This item starts capturing packets with the
options from the last time.

[ Stop ]

Capture › Stop

This item stops the currently running live
capture process Start Capturing).

[ Restart ]

Capture › Restart

This item stops the currently running live
capture process and restarts it again, for
convenience.

[ Open… ]

File › Open…

This item brings up the file open dialog box
that allows you to load a capture file for
viewing. It is discussed in more detail in
The “Open Capture File” dialog box.

[ Save As… ]

File › Save As…

This item allows you to save the current
capture file to whatever file you would
like. It pops up the Save Capture File As
dialog box (which is discussed further in
The “Save Capture File As” dialog box).
If you currently have a temporary capture
file, the Save icon will be shown instead.

[ Close ]

File › Close

This item closes the current capture. If you
have not saved the capture, you will be
asked to save it first.

[ Reload ]

View › Reload

This item allows you to reload the current
capture file.

[ Print… ]

File › Print…

This item allows you to print all (or some
of) the packets in the capture file. It pops
up the Wireshark Print dialog box (which
is discussed further in Printing packets).

[ Find Packet… ]

Edit › Find Packet… This item brings up a dialog box that
allows you to find a packet. There is
further information on finding packets in
Finding packets.

[ Go Back ]

Go › Go Back

This item jumps back in the packet history.
Hold down the Alt key (Option on macOS)
to go back in the selection history.

[ Go Forward ]

Go › Go Forward

This item jumps forward in the packet
history. Hold down the Alt key (Option on
macOS) to go forward in the selection
history.

[ Go to Packet… ]

Go › Go to Packet…

This item brings up a dialog box that
allows you to specify a packet number to
go to that packet.

Toolbar
Icon

Toolbar Item

Menu Item

Description

[ Go To First
Packet ]

Go › First Packet

This item jumps to the first packet of the
capture file.

[ Go To Last
Packet ]

Go › Last Packet

This item jumps to the last packet of the
capture file.

[ Colorize ]

View › Colorize

Colorize the packet list (or not).

[ Auto Scroll in Live View › Auto Scroll
Capture ]
in Live Capture

Auto scroll packet list while doing a live
capture (or not).

[ Zoom In ]

View › Zoom In

Zoom into the packet data (increase the
font size).

[ Zoom Out ]

View › Zoom Out

Zoom out of the packet data (decrease the
font size).

[ Normal Size ]

View › Normal Size

Set zoom level back to 100%.

[ Resize Columns ]

View › Resize
Columns

Resize columns, so the content fits into
them.

[ Capture Filters… ] Capture › Capture
Filters…

This item brings up a dialog box that
allows you to create and edit capture
filters. You can name filters, and you can
save them for future use. More detail on
this subject is provided in Defining and
saving filters.

[ Display Filters… ]

Analyze › Display
Filters…

This item brings up a dialog box that
allows you to create and edit display
filters. You can name filters, and you can
save them for future use. More detail on
this subject is provided in Defining and
saving filters.

[ Coloring Rules… ]

View › Coloring
Rules…

This item brings up a dialog box that
allows you to color packets in the packet
list pane according to filter expressions
you choose. It can be very useful for
spotting certain types of packets. More
detail on this subject is provided in Packet
colorization.

[ Preferences… ]

Edit › Preferences

This item brings up a dialog box that
allows you to set preferences for many
parameters that control Wireshark. You
can also save your preferences so
Wireshark will use them the next time you
start it. More detail is provided in
Preferences

[ Help ]

Help › Contents

This item brings up help dialog box.

The “Filter” Toolbar
The filter toolbar lets you quickly edit and apply display filters. More information on display filters
is available in Filtering packets while viewing.

Figure 16. The “Filter” toolbar
Table 15. Filter toolbar items

Toolbar
Icon

Toolbar Item

Description

[ Filter: ]

Brings up the filter construction dialog, described in
The “Capture Filters” and “Display Filters” dialog boxes.

Filter input

The area to enter or edit a display filter string, see
Building display filter expressions. A syntax check of
your filter string is done while you are typing. The
background will turn red if you enter an incomplete or
invalid string, and will become green when you enter a
valid string. You can click on the pull down arrow to
select a previously-entered filter string from a list. The
entries in the pull down list will remain available even
after a program restart.
After you’ve changed something in this field, don’t
forget to press the Apply button (or the Enter/Return
key), to apply this filter string to the display.
This field is also where the current filter in effect is
displayed.

[ Expression… ]

The middle button labeled “Add Expression…” opens a
dialog box that lets you edit a display filter from a list of
protocol fields, described in The “Filter Expression”
dialog box

[ Clear ]

Reset the current display filter and clears the edit area.

[ Apply ]

Apply the current value in the edit area as the new
display filter.
Applying a display filter on large capture files might
take quite a long time.

The “Packet List” Pane
The packet list pane displays all the packets in the current capture file.

Figure 17. The “Packet List” pane

Each line in the packet list corresponds to one packet in the capture file. If you select a line in this
pane, more details will be displayed in the “Packet Details” and “Packet Bytes” panes.
While dissecting a packet, Wireshark will place information from the protocol dissectors into the
columns. As higher level protocols might overwrite information from lower levels, you will
typically see the information from the highest possible level only.
For example, let’s look at a packet containing TCP inside IP inside an Ethernet packet. The Ethernet
dissector will write its data (such as the Ethernet addresses), the IP dissector will overwrite this by
its own (such as the IP addresses), the TCP dissector will overwrite the IP information, and so on.
There are a lot of different columns available. Which columns are displayed can be selected by
preference settings, see Preferences.
The default columns will show:
• [ No. ] The number of the packet in the capture file. This number won’t change, even if a display
filter is used.
• [ Time ] The timestamp of the packet. The presentation format of this timestamp can be
changed, see Time display formats and time references.
• [ Source ] The address where this packet is coming from.
• [ Destination ] The address where this packet is going to.
• [ Protocol ] The protocol name in a short (perhaps abbreviated) version.
• [ Length ] The length of each packet.
• [ Info ] Additional information about the packet content.
The first column shows how each packet is related to the selected packet. For example, in the image
above the first packet is selected, which is a DNS request. Wireshark shows a rightward arrow for
the request itself, followed by a leftward arrow for the response in packet 2. Why is there a dashed
line? There are more DNS packets further down that use the same port numbers. Wireshark treats
them as belonging to the same conversation and draws a line connecting them.
Related packet symbols

First packet in a conversation.

Part of the selected conversation.

Not part of the selected conversation.

Last packet in a conversation.

Request.

Response.

The selected packet acknowledges this packet.

The selected packet is a duplicate acknowledgement of this packet.

The selected packet is related to this packet in some other way, e.g. as part of reassembly.
The packet list has an Intelligent Scrollbar which shows a miniature map of nearby packets. Each
raster line of the scrollbar corresponds to a single packet, so the number of packets shown in the
map depends on your physical display and the height of the packet list. A tall packet list on a highresolution (“Retina”) display will show you quite a few packets. In the image above the scrollbar
shows the status of more than 500 packets along with the 15 shown in the packet list itself.
Right clicking will show a context menu, described in Pop-up menu of the “Packet List” pane.

The “Packet Details” Pane
The packet details pane shows the current packet (selected in the “Packet List” pane) in a more
detailed form.

Figure 18. The “Packet Details” pane

This pane shows the protocols and protocol fields of the packet selected in the “Packet List” pane.
The protocols and fields of the packet shown in a tree which can be expanded and collapsed.
There is a context menu (right mouse click) available. See details in Pop-up menu of the “Packet
Details” pane.
Some protocol fields have special meanings.
• Generated fields. Wireshark itself will generate additional protocol information which isn’t
present in the captured data. This information is enclosed in square brackets (“[” and “]”).
Generated information includes response times, TCP analysis, IP geolocation information, and
checksum validation.
• Links. If Wireshark detects a relationship to another packet in the capture file it will generate a
link to that packet. Links are underlined and displayed in blue. If you double-clicked on a link
Wireshark will jump to the corresponding packet.

The “Packet Bytes” Pane
The packet bytes pane shows the data of the current packet (selected in the “Packet List” pane) in a
hexdump style.

Figure 19. The “Packet Bytes” pane

The “Packet Bytes” pane shows a canonical hex dump of the packet data. Each line contains the data
offset, sixteen hexadecimal bytes, and sixteen ASCII bytes. Non-printalbe bytes are replaced with a
period (“.”).
Depending on the packet data, sometimes more than one page is available, e.g. when Wireshark has

reassembled some packets into a single chunk of data. (See Packet Reassembly for details). In this
case you can see each data source by clicking its corresponding tab at the bottom of the pane.

Figure 20. The “Packet Bytes” pane with tabs

Additional pages typically contain data reassembled from multiple packets or decrypted data.
The context menu (right mouse click) of the tab labels will show a list of all available pages. This
can be helpful if the size in the pane is too small for all the tab labels.

The Statusbar
The statusbar displays informational messages.
In general, the left side will show context related information, the middle part will show
information about the current capture file, and the right side will show the selected configuration
profile. Drag the handles between the text areas to change the size.

Figure 21. The initial Statusbar

This statusbar is shown while no capture file is loaded, e.g. when Wireshark is started.

Figure 22. The Statusbar with a loaded capture file

• The colorized bullet on the left shows the highest expert info level found in the currently
loaded capture file. Hovering the mouse over this icon will show a textual description of the
expert info level, and clicking the icon will bring up the Expert Infos dialog box. For a detailed
description of expert info, see Expert Information.
• The left side shows information about the capture file, its name, its size and the elapsed time
while it was being captured. Hovering over a file name will show its full path and size.
• The middle part shows the current number of packets in the capture file. The following values
are displayed:
◦ Packets: The number of captured packets.
◦ Displayed: The number of packets currently being displayed.
◦ Marked: The number of marked packets (only displayed if packets are marked).
◦ Dropped: The number of dropped packets (only displayed if Wireshark was unable to

capture all packets).
◦ Ignored: The number of ignored packets (only displayed if packets are ignored).
◦ Load time: The time it took to load the capture (wall clock time).
• The right side shows the selected configuration profile. Clicking in this part of the statusbar
will bring up a menu with all available configuration profiles, and selecting from this list will
change the configuration profile.

Figure 23. The Statusbar with a configuration profile menu

For a detailed description of configuration profiles, see Configuration Profiles.

Figure 24. The Statusbar with a selected protocol field

This is displayed if you have selected a protocol field from the “Packet Details” pane.
TIP

The value between the parentheses (in this example “ipv6.src”) can be used as a
display filter, representing the selected protocol field.

Figure 25. The Statusbar with a display filter message

This is displayed if you are trying to use a display filter which may have unexpected results. For a
detailed description, see A Common Mistake.

Capturing Live Network Data
Introduction
Capturing live network data is one of the major features of Wireshark.
The Wireshark capture engine provides the following features:
• Capture from different kinds of network hardware such as Ethernet or 802.11.
• Stop the capture on different triggers such as the amount of captured data, elapsed time, or the
number of packets.
• Simultaneously show decoded packets while Wireshark is capturing.
• Filter packets, reducing the amount of data to be captured. See Filtering while capturing.
• Save packets in multiple files while doing a long term capture, optionally rotating through a
fixed number of files (a “ringbuffer”). See Capture files and file modes.
• Simultaneously capture from multiple network interfaces.
The capture engine still lacks the following features:
• Stop capturing (or perform some other action) depending on the captured data.

Prerequisites
Setting up Wireshark to capture packets for the first time can be tricky. A comprehensive guide
“How To setup a Capture” is available at https://wiki.wireshark.org/CaptureSetup.
Here are some common pitfalls:
• You may need special privileges to start a live capture.
• You need to choose the right network interface to capture packet data from.
• You need to capture at the right place in the network to see the traffic you want to see.
If you have any problems setting up your capture environment you should have a look at the guide
mentioned above.

Start Capturing
The following methods can be used to start capturing packets with Wireshark:
• You can double-click on an interface in the main window.
• You can get an overview of the available interfaces using the “Capture Interfaces” dialog box

(Capture › Options…). See The “Capture Interfaces” dialog box on Microsoft Windows or The
“Capture Interfaces” dialog box on Unix/Linux for more information. You can start a capture
from this dialog box using the [ Start ] button.
• You can immediately start a capture using your current settings by selecting Capture › Start or
by cliking the first toolbar button.
• If you already know the name of the capture interface you can start Wireshark from the
command line:

$ wireshark -i eth0 -k
This will start Wireshark capturing on interface eth0. More details can be found at Start Wireshark
from the command line.

The “Capture Interfaces” dialog box
When you select Capture › Options… from the main menu Wireshark pops up the “Capture
Interfaces” dialog box as shown in The “Capture Interfaces” dialog box on Microsoft Windows or
The “Capture Interfaces” dialog box on Unix/Linux.
Both you and your OS can hide interfaces

NOTE

This dialog box will only show the local interfaces Wireshark can access. It will also
hide interfaces marked as hidden in Interface Options. As Wireshark might not be
able to detect all local interfaces and it cannot detect the remote interfaces available
there could be more capture interfaces available than listed.

It is possible to select more than one interface and capture from them simultaneously.

Figure 26. The “Capture Interfaces” dialog box on Microsoft Windows

Figure 27. The “Capture Interfaces” dialog box on Unix/Linux

Device (Unix/Linux only)
The interface device name.
Description
The interface description provided by the operating system, or the user defined comment added
in Interface Options.
IP
The first IP address Wireshark could find for this interface. You can click on the address to cycle
through other addresses assigned to it, if available. If no address could be found “none” will be
displayed.
Packets
The number of packets captured from this interface, since this dialog was opened. Will be
greyed out, if no packet was captured in the last second.
Packets/s
Number of packets captured in the last second. Will be greyed out, if no packet was captured in
the last second.
Stop
Stop a currently running capture.
Start
Start a capture on all selected interfaces immediately, using the settings from the last capture or
the default settings, if no options have been set.
Options
Open the Capture Options dialog with the marked interfaces selected. See The “Capture Options”
dialog box.
Details (Microsoft Windows only)

Open a dialog with detailed information about the interface. See The “Interface Details” dialog
box.
Help
Show this help page.
Close
Close this dialog box.

The “Capture Options” dialog box
When you select Capture › Options… (or use the corresponding item in the main toolbar),
Wireshark pops up the “Capture Options” dialog box as shown in The “Capture Options” dialog box.

Figure 28. The “Capture Options” dialog box

TIP

If you are unsure which options to choose in this dialog box just try keeping the
defaults as this should work well in many cases.

Capture frame
The table shows the settings for all available interfaces:
• The name of the interface and its IP addresses. If no address could be resolved from the system,
“none” will be shown.
NOTE

Loopback interfaces are not available on Windows platforms.

• The link-layer header type.
• The information whether promicuous mode is enabled or disabled.
• The maximum amount of data that will be captured for each packet. The default value is set to
the 262144 bytes.
• The size of the kernel buffer that is reserved to keep the captured packets.
• The information whether packets will be captured in monitor mode (Unix/Linux only).
• The chosen capture filter.
By marking the checkboxes in the first column the interfaces are selected to be captured from. By
double-clicking on an interface the “Edit Interface Settings” dialog box as shown in The “Edit
Interface Settings” dialog box will be opened.
Capture on all interfaces
As Wireshark can capture on multiple interfaces it is possible to choose to capture on all
available interfaces.
Capture all packets in promiscuous mode
This checkbox allows you to specify that Wireshark should put all interfaces in promiscuous
mode when capturing.
Capture Filter
This field allows you to specify a capture filter for all interfaces that are currently selected. Once
a filter has been entered in this field, the newly selected interfaces will inherit the filter. Capture
filters are discussed in more details in Filtering while capturing. It defaults to empty, or no filter.
You can also click on the [ Capture Filter ] button and Wireshark will bring up the Capture
Filters dialog box and allow you to create and/or select a filter. Please see Defining and saving
filters
Compile selected BPFs
This button allows you to compile the capture filter into BPF code and pop up a window showing

you the resulting pseudo code. This can help in understanding the working of the capture filter
you created. The [ Compile Selected BPFs ] button leads you to The “Compile Results” dialog
box.
TIP

Linux power user tip

The execution of BPFs can be sped up on Linux by turning on BPF JIT by executing

$ echo 1 >/proc/sys/net/core/bpf_jit_enable
if it is not enabled already. To make the change persistent you can use sysfsutils.
Manage Interfaces
The [ Manage Interfaces ] button opens the The “Add New Interfaces” dialog box where pipes
can be defined, local interfaces scanned or hidden, or remote interfaces added (Windows only).

Capture File(s) frame
An explanation about capture file usage can be found in Capture files and file modes.
File
This field allows you to specify the file name that will be used for the capture file. This field is
left blank by default. If the field is left blank, the capture data will be stored in a temporary file.
See Capture files and file modes for details.
You can also click on the button to the right of this field to browse through the filesystem.
Use multiple files
Instead of using a single file Wireshark will automatically switch to a new one if a specific
trigger condition is reached.
Use pcapng format
This checkbox allows you to specify that Wireshark saves the captured packets in pcapng
format. This next generation capture file format is currently in development. If more than one
interface is chosen for capturing, this checkbox is set by default. See https://wiki.wireshark.org/
Development/PcapNg for more details on pcapng.
Next file every n megabyte(s)
Multiple

files

only.

Switch

the

file

after

the

given

number

the

given

number

byte(s)/kilobyte(s)/megabyte(s)/gigabyte(s) have been captured.
Next file every n minute(s)
Multiple

files

only:

Switch

the

file

after

second(s)/minutes(s)/hours(s)/days(s) have elapsed.
Ring buffer with n files
Multiple files only: Form a ring buffer of the capture files with the given number of files.
Stop capture after n file(s)
Multiple files only: Stop capturing after switching to the next file the given number of times.

Stop Capture… frame
… after n packet(s)
Stop capturing after the given number of packets have been captured.
… after n megabytes(s)
Stop capturing after the given number of byte(s)/kilobyte(s)/megabyte(s)/gigabyte(s) have been
captured. This option is greyed out if “Use multiple files” is selected.
… after n minute(s)
Stop capturing after the given number of second(s)/minutes(s)/hours(s)/days(s) have elapsed.

Display Options frame
Update list of packets in real time
This option allows you to specify that Wireshark should update the packet list pane in real time.
If you do not specify this, Wireshark does not display any packets until you stop the capture.
When you check this, Wireshark captures in a separate process and feeds the captures to the
display process.
Automatic scrolling in live capture
This option allows you to specify that Wireshark should scroll the packet list pane as new
packets come in, so you are always looking at the last packet. If you do not specify this
Wireshark simply adds new packets onto the end of the list but does not scroll the packet list
pane. This option is greyed out if “Update list of packets in real time” is disabled.

Name Resolution frame
Enable MAC name resolution
This option allows you to control whether or not Wireshark translates MAC addresses into
names. See Name Resolution.
Enable network name resolution
This option allows you to control whether or not Wireshark translates network addresses into
names. See Name Resolution.

Enable transport name resolution
This option allows you to control whether or not Wireshark translates transport addresses into
protocols. See Name Resolution.

Buttons
Once you have set the values you desire and have selected the options you need, simply click on
[ Start ] to commence the capture or [ Cancel ] to cancel the capture.

The “Edit Interface Settings” dialog box
If you double-click on an interface in The “Capture Options” dialog box the following dialog box
pops up.

Figure 29. The “Edit Interface Settings” dialog box

You can set the following fields in this dialog box:
IP address
The IP address(es) of the selected interface. If no address could be resolved from the system
“none” will be shown.
Link-layer header type
Unless you are in the rare situation that requires this keep the default setting. For a detailed
description. See Link-layer header type
Wireless settings (Windows only)
Here you can set the settings for wireless capture using the AirPCap adapter. For a detailed
description see the AirPCap Users Guide.
Remote settings (Windows only)

Here you can set the settings for remote capture. For a detailed description see The “Remote
Capture Interfaces” dialog box
Capture packets in promiscuous mode
This checkbox allows you to specify that Wireshark should put the interface in promiscuous
mode when capturing. If you do not specify this Wireshark will only capture the packets going to
or from your computer (not all packets on your LAN segment).
If some other process has put the interface in promiscuous mode you may be
NOTE

capturing in promiscuous mode even if you turn off this option.
Even in promiscuous mode you still won’t necessarily see all packets on your LAN
segment. See the Wireshark FAQ for more information.

Limit each packet to n bytes
This field allows you to specify the maximum amount of data that will be captured for each
packet, and is sometimes referred to as the snaplen. If disabled the value is set to the maximum
65535 which will be sufficient for most protocols. Some rules of thumb:
• If you are unsure just keep the default value.
• If you don’t need or don’t want all of the data in a packet - for example, if you only need the
link-layer, IP, and TCP headers - you might want to choose a small snapshot length, as less
CPU time is required for copying packets, less buffer space is required for packets, and thus
perhaps fewer packets will be dropped if traffic is very heavy.
• If you don’t capture all of the data in a packet you might find that the packet data you want is
in the part that’s dropped or that reassembly isn’t possible as the data required for
reassembly is missing.
Buffer size: n megabyte(s)
Enter the buffer size to be used while capturing. This is the size of the kernel buffer which will
keep the captured packets, until they are written to disk. If you encounter packet drops, try
increasing this value.
Capture packets in monitor mode (Unix/Linux only)
This checkbox allows you to setup the Wireless interface to capture all traffic it can receive, not
just the traffic on the BSS to which it is associated, which can happen even when you set
promiscuous mode. Also it might be necessary to turn this option on in order to see IEEE 802.11
headers and/or radio information from the captured frames.
NOTE

In monitor mode the adapter might disassociate itself from the network it was
associated to.

Capture Filter
This field allows you to specify a capture filter. Capture filters are discussed in more details in

Filtering while capturing. It defaults to empty, or no filter.
You can also click on the [ Capture Filter ] button and Wireshark will bring up the “Capture
Filters” dialog box and allow you to create and/or select a filter. Please see Defining and saving
filters
Compile BPF
This button allows you to compile the capture filter into BPF code and pop up a window showing
you the resulting pseudo code. This can help in understanding the working of the capture filter
you created.

The “Compile Results” dialog box
This figure shows the compile results of the selected interfaces.

Figure 30. The “Compile Results” dialog box

In the left window the interface names are listed. The results of an individual interface are shown
in the right window when it is selected.

The “Add New Interfaces” dialog box
As a central point to manage interfaces this dialog box consists of three tabs to add or remove
interfaces.

Figure 31. The “Add New Interfaces” dialog box

Add or remove pipes

Figure 32. The “Add New Interfaces - Pipes” dialog box

To successfully add a pipe, this pipe must have already been created. Click the [ New ] button and
type the name of the pipe including its path. Alternatively, the [ Browse ] button can be used to
locate the pipe. With the [ Save ] button the pipe is added to the list of available interfaces.
Afterwards, other pipes can be added.
To remove a pipe from the list of interfaces it first has to be selected. Then click the [ Delete ]
button.

Add or hide local interfaces

Figure 33. The “Add New Interfaces - Local Interfaces” dialog box

The tab “Local Interfaces” contains a list of available local interfaces, including the hidden ones,
which are not shown in the other lists.
If a new local interface is added, for example, a wireless interface has been activated, it is not
automatically added to the list to prevent the constant scanning for a change in the list of available
interfaces. To renew the list a rescan can be done.
One way to hide an interface is to change the preferences. If the “Hide” checkbox is activated and
the [ Apply ] button clicked, the interface will not be seen in the lists of the “Capture Interfaces”
dialog box any more. The changes are also saved in the preferences file.

Add or hide remote interfaces

Figure 34. The “Add New Interfaces - Remote Interfaces” dialog box

In this tab interfaces on remote hosts can be added. One or more of these interfaces can be hidden.
In contrast to the local interfaces they are not saved in the preferences file.
To remove a host including all its interfaces from the list, it has to be selected. Then click the
[ Delete ] button.
For a detailed description see The “Remote Capture Interfaces” dialog box

The “Remote Capture Interfaces” dialog box
Besides doing capture on local interfaces Wireshark is capable of reaching out across the network
to a so called capture daemon or service processes to receive captured data from.
Microsoft Windows only

NOTE

This dialog and capability is only available on Microsoft Windows. On Linux/Unix
you can achieve the same effect (securely) through an SSH tunnel.

The Remote Packet Capture Protocol service must first be running on the target platform before
Wireshark can connect to it. The easiest way is to install WinPcap from https://www.winpcap.org/
install/ on the target. Once installation is completed go to the Services control panel, find the
Remote Packet Capture Protocol service and start it.
NOTE

Make sure you have outside access to port 2002 on the target platform. This is the
port where the Remote Packet Capture Protocol service can be reached by default.

To access the Remote Capture Interfaces dialog use the “Add New Interfaces - Remote” dialog. See
The “Add New Interfaces - Remote Interfaces” dialog box and select [ Add ].

Remote Capture Interfaces

Figure 35. The “Remote Capture Interfaces” dialog box

You have to set the following parameters in this dialog:
Host
Enter the IP address or host name of the target platform where the Remote Packet Capture
Protocol service is listening. The drop down list contains the hosts that have previously been
successfully contacted. The list can be emptied by choosing “Clear list” from the drop down list.
Port
Set the port number where the Remote Packet Capture Protocol service is listening on. Leave
open to use the default port (2002).
Null authentication
Select this if you don’t need authentication to take place for a remote capture to be started. This
depends on the target platform. Configuring the target platform like this makes it insecure.
Password authentication
This is the normal way of connecting to a target platform. Set the credentials needed to connect
to the Remote Packet Capture Protocol service.

Remote Capture Settings
The remote capture can be further fine tuned to match your situation. The [ Remote Settings ]
button in The “Edit Interface Settings” dialog box gives you this option. It pops up the dialog shown
in The “Remote Capture Settings” dialog box.

Figure 36. The “Remote Capture Settings” dialog box

You can set the following parameters in this dialog:
Do not capture own RPCAP traffic
This option sets a capture filter so that the traffic flowing back from the Remote Packet Capture
Protocol service to Wireshark isn’t captured as well and also send back. The recursion in this
saturates the link with duplicate traffic.
You only should switch this off when capturing on an interface other than the interface
connecting back to Wireshark.
Use UDP for data transfer
Remote capture control and data flows over a TCP connection. This option allows you to choose
an UDP stream for data transfer.
Sampling option None
This option instructs the Remote Packet Capture Protocol service to send back all captured
packets which have passed the capture filter. This is usually not a problem on a remote capture
session with sufficient bandwidth.
Sampling option 1 of x packets
This option limits the Remote Packet Capture Protocol service to send only a sub sampling of the
captured data, in terms of number of packets. This allows capture over a narrow band remote
capture session of a higher bandwidth interface.
Sampling option 1 every x milliseconds
This option limits the Remote Packet Capture Protocol service to send only a sub sampling of the
captured data in terms of time. This allows capture over a narrow band capture session of a
higher bandwidth interface.

The “Interface Details” dialog box
When you select Details from the Capture Interface menu, Wireshark pops up the “Interface
Details” dialog box as shown in The “Interface Details” dialog box. This dialog shows various
characteristics and statistics for the selected interface.

NOTE

Microsoft Windows only

This dialog is only available on Microsoft Windows

Figure 37. The “Interface Details” dialog box

Capture files and file modes
While capturing the underlying libpcap capturing engine will grab the packets from the network
card and keep the packet data in a (relatively) small kernel buffer. This data is read by Wireshark
and saved into a capture file.
By default Wireshark saves packets to a temporary file. You can also tell Wireshark to save to a
specific (“permanent”) file and switch to a different file after a given time has elapsed or a given
number of packets have been captured. These options are controlled in the “Output” tab in the
“Capture Options” dialog.

Figure 38. Capture output options

Working with large files (several hundred MB) can be quite slow. If you plan to do a
TIP

long term capture or capturing from a high traffic network, think about using one of
the “Multiple files” options. This will spread the captured packets over several smaller
files which can be much more pleasant to work with.

Using Multiple files may cut context related information. Wireshark keeps context information of
the loaded packet data, so it can report context related problems (like a stream error) and keeps
information about context related protocols (e.g. where data is exchanged at the establishing phase
and only referred to in later packets). As it keeps this information only for the loaded file, using one
of the multiple file modes may cut these contexts. If the establishing phase is saved in one file and
the things you would like to see is in another, you might not see some of the valuable context
related information.
Information about the folders used for capture files can be found in Files and Folders.
Table 16. Capture file mode selected by capture options

File Name

“Create a
new file…”

“Use a ring
buffer…”

Mode

Resulting filename(s) used

Single temporary file wiresharkXXXXXX (where
XXXXXX is a unique number)

foo.cap

Single named file

foo.cap

Multiple files,
continuous

foo_00001_20100205110102.cap,
foo_00002_20100205110318.cap, …

foo.cap

Multiple files, ring
buffer

foo_00001_20100205110102.cap,
foo_00002_20100205110318.cap, …

Single temporary file
A temporary file will be created and used (this is the default). After capturing is stopped this file
can be saved later under a user specified name.
Single named file
A single capture file will be used. If you want to place the new capture file in a specific folder
choose this mode.
Multiple files, continuous
Like the “Single named file” mode, but a new file is created and used after reaching one of the
multiple file switch conditions (one of the “Next file every …” values).
Multiple files, ring buffer
Much like “Multiple files continuous”, reaching one of the multiple files switch conditions (one
of the “Next file every …” values) will switch to the next file. This will be a newly created file if
value of “Ring buffer with n files” is not reached, otherwise it will replace the oldest of the
formerly used files (thus forming a “ring”). + This mode will limit the maximum disk usage, even
for an unlimited amount of capture input data, only keeping the latest captured data.

Link-layer header type
In most cases you won’t have to modify link-layer header type. Some exceaptions are as follows:
If you are capturing on an Ethernet device you might be offered a choice of “Ethernet” or “DOCSIS”.
If you are capturing traffic from a Cisco Cable Modem Termination System that is putting DOCSIS
traffic onto the Ethernet to be captured, select “DOCSIS”, otherwise select “Ethernet”.
If you are capturing on an 802.11 device on some versions of BSD you might be offered a choice of
“Ethernet” or “802.11”. “Ethernet” will cause the captured packets to have fake (“cooked”) Ethernet
headers. “802.11” will cause them to have full IEEE 802.11 headers. Unless the capture needs to be
read by an application that doesn’t support 802.11 headers you should select “802.11”.
If you are capturing on an Endace DAG card connected to a synchronous serial line you might be
offered a choice of “PPP over serial” or “Cisco HDLC”. If the protocol on the serial line is PPP, select
“PPP over serial” and if the protocol on the serial line is Cisco HDLC, select “Cisco HDLC”.
If you are capturing on an Endace DAG card connected to an ATM network you might be offered a
choice of “RFC 1483 IP-over-ATM” or “Sun raw ATM”. If the only traffic being captured is RFC 1483
LLC-encapsulated IP, or if the capture needs to be read by an application that doesn’t support
SunATM headers, select “RFC 1483 IP-over-ATM”, otherwise select “Sun raw ATM”.

Filtering while capturing
Wireshark uses the libpcap filter language for capture filters. A brief overview of the syntax
follows. Complete documentation can be found in the pcap-filter man page. You can find a lot of

Capture Filter examples at https://wiki.wireshark.org/CaptureFilters.
You enter the capture filter into the “Filter” field of the Wireshark “Capture Options” dialog box, as
shown in The “Capture Options” dialog box.
A capture filter takes the form of a series of primitive expressions connected by conjunctions
(and/or) and optionally preceded by not:

[not] primitive [and|or [not] primitive ...]
An example is shown in A capture filter for telnet that captures traffic to and from a particular host.
Example 1. A capture filter for telnet that captures traffic to and from a particular host

A capture filter for telnet that captures traffic to and from a particular host

tcp port 23 and host 10.0.0.5

This example captures telnet traffic to and from the host 10.0.0.5, and shows how to use two
primitives and the and conjunction. Another example is shown in Capturing all telnet traffic not
from 10.0.0.5, and shows how to capture all telnet traffic except that from 10.0.0.5.
Example 2. Capturing all telnet traffic not from 10.0.0.5

Capturing all telnet traffic not from 10.0.0.5

tcp port 23 and not src host 10.0.0.5

A primitive is simply one of the following: [src|dst] host
This primitive allows you to filter on a host IP address or name. You can optionally precede the
primitive with the keyword src|dst to specify that you are only interested in source or
destination addresses. If these are not present, packets where the specified address appears as
either the source or the destination address will be selected.
ether [src|dst] host
This primitive allows you to filter on Ethernet host addresses. You can optionally include the
keyword src|dst between the keywords ether and host to specify that you are only interested in
source or destination addresses. If these are not present, packets where the specified address
appears in either the source or destination address will be selected.
gateway host

This primitive allows you to filter on packets that used host as a gateway. That is, where the
Ethernet source or destination was host but neither the source nor destination IP address was
host.
[src|dst] net [{mask }|{len }]
This primitive allows you to filter on network numbers. You can optionally precede this
primitive with the keyword src|dst to specify that you are only interested in a source or
destination network. If neither of these are present, packets will be selected that have the
specified network in either the source or destination address. In addition, you can specify either
the netmask or the CIDR prefix for the network if they are different from your own.
[tcp|udp] [src|dst] port
This primitive allows you to filter on TCP and UDP port numbers. You can optionally precede this
primitive with the keywords src|dst and tcp|udp which allow you to specify that you are only
interested in source or destination ports and TCP or UDP packets respectively. The keywords
tcp|udp must appear before src|dst.
If these are not specified, packets will be selected for both the TCP and UDP protocols and when
the specified address appears in either the source or destination port field.
less|greater
This primitive allows you to filter on packets whose length was less than or equal to the
specified length, or greater than or equal to the specified length, respectively.
ip|ether proto
This primitive allows you to filter on the specified protocol at either the Ethernet layer or the IP
layer.
ether|ip broadcast|multicast
This primitive allows you to filter on either Ethernet or IP broadcasts or multicasts.
relop
This primitive allows you to create complex filter expressions that select bytes or ranges of bytes
in packets. Please see the pcap-filter man page at http://www.tcpdump.org/manpages/pcapfilter.7.html for more details.

Automatic Remote Traffic Filtering
If Wireshark is running remotely (using e.g. SSH, an exported X11 window, a terminal server, …),
the remote content has to be transported over the network, adding a lot of (usually unimportant)
packets to the actually interesting traffic.
To avoid this, Wireshark tries to figure out if it’s remotely connected (by looking at some specific
environment variables) and automatically creates a capture filter that matches aspects of the
connection.

The following environment variables are analyzed:
SSH_CONNECTION (ssh)

SSH_CLIENT (ssh)

REMOTEHOST (tcsh, others?)

DISPLAY (x11)
[remote name]:
SESSIONNAME (terminal server)

On Windows it asks the operating system if it’s running in a Remote Desktop Services environment.

While a Capture is running …
You might see the following dialog box while a capture is running:

Figure 39. The “Capture Information” dialog box

This dialog box shows a list of protocols and their activity over time. It can be enabled via the
“capture.show_info” setting in the “Advanced” preferences.

Stop the running capture
A running capture session will be stopped in one of the following ways:
1. The [ Stop Capture ] button in the “Capture Information” dialog box.
2. The Capture › Stop menu item.
3. The [ Stop ] toolbar button.
4. Pressing Ctrl+E.
5. The capture will be automatically stopped if one of the Stop Conditions is met, e.g. the maximum

amount of data was captured.

Restart a running capture
A running capture session can be restarted with the same capture options as the last time, this will
remove all packets previously captured. This can be useful, if some uninteresting packets are
captured and there’s no need to keep them.
Restart is a convenience function and equivalent to a capture stop following by an immediate
capture start. A restart can be triggered in one of the following ways:
1. Using the Capture › Restart menu item.
2. Using the [ Restart ] toolbar button.

File Input, Output, and Printing
Introduction
This chapter will describe input and output of capture data.
• Open capture files in various capture file formats
• Save/Export capture files in various capture file formats
• Merge capture files together
• Import text files containing hex dumps of packets
• Print packets

Open capture files
Wireshark can read in previously saved capture files. To read them, simply select the File › Open
menu or toolbar item. Wireshark will then pop up the “File Open” dialog box, which is discussed in
more detail in The “Open Capture File” dialog box.
It’s convenient to use drag-and-drop

TIP

You can open a file by simply dragging it in your file manager and dropping it onto
Wireshark’s main window. However, drag-and-drop may not be available in all
desktop environments.

If you haven’t previously saved the current capture file you will be asked to do so to prevent data
loss. This warning can be disabled in the preferences.
In addition to its native file format (pcapng), Wireshark can read and write capture files from a
large number of other packet capture programs as well. See Input File Formats for the list of
capture formats Wireshark understands.

The “Open Capture File” dialog box
The “Open Capture File” dialog box allows you to search for a capture file containing previously
captured packets for display in Wireshark. The following sections show some examples of the
Wireshark “Open File” dialog box. The appearance of this dialog depends on the system. However,
the functionality should be the same across systems.
Common dialog behaviour on all systems:
• Select files and directories.
• Click the [ Open ] or [ OK ] button to accept your selected file and open it.
• Click the [ Cancel ] button to go back to Wireshark and not load a capture file.
77

Wireshark extensions to the standard behaviour of these dialogs:
• View file preview information such as the filesize and the number of packets in a selected a
capture file.
• Specify a display filter with the [ Filter ] button and filter field. This filter will be used when
opening the new file. The text field background becomes green for a valid filter string and red
for an invalid one. Clicking on the [ Filter ] button causes Wireshark to pop up the “Filters”
dialog box (which is discussed further in Filtering packets while viewing).
• Specify which type of name resolution is to be performed for all packets by clicking on one of
the “… name resolution” check buttons. Details about name resolution can be found in Name
Resolution.
Save a lot of time loading huge capture files

TIP

You can change the display filter and name resolution settings later while viewing the
packets. However, loading huge capture files can take a significant amount of extra
time if these settings are changed later, so in such situations it can be a good idea to
set at least the filter in advance here.

Figure 40. “Open” on Microsoft Windows

This is the common Windows file open dialog - plus some Wireshark extensions.
Specific for this dialog:
• The [ Help ] button will lead you to this section of this “User’s Guide”.

Figure 41. “Open” - Linux and UNIX

This is the common Gimp/GNOME file open dialog plus some Wireshark extensions.
Specific for this dialog:
• The [ + ] button allows you to add a directory selected in the right-hand pane to the favorites list
on the left. These changes are persistent.
• The [ - ] button allows you to remove a selected directory from the list. Some items (such as
“Desktop”) cannot be removed from the favorites list.
• If Wireshark doesn’t recognize the selected file as a capture file it will grey out the [ Open ]
button.

Input File Formats
The following file formats from other capture tools can be opened by Wireshark:
• pcapng. A flexible, etensible successor to the libpcap format. Wireshark 1.8 and later save files
as pcapng by default. Versions prior to 1.8 used libpcap.
• libpcap. The default format used by the libpcap packet capture library. Used by tcpdump, _Snort,
Nmap, Ntop, and many other tools.
• Oracle (previously Sun) snoop and atmsnoop
• Finisar (previously Shomiti) Surveyor captures

• Microsoft Network Monitor captures
• Novell LANalyzer captures
• AIX iptrace captures
• Cinco Networks NetXray captures
• Network Associates Windows-based Sniffer and Sniffer Pro captures
• Network General/Network Associates DOS-based Sniffer (compressed or uncompressed)
captures
• AG

Group/WildPackets/Savvius

EtherPeek/TokenPeek/AiroPeek/EtherHelp/PacketGrabber

captures
• RADCOM’s WAN/LAN Analyzer captures
• Network Instruments Observer version 9 captures
• Lucent/Ascend router debug output
• HP-UX’s nettl
• Toshiba’s ISDN routers dump output
• ISDN4BSD i4btrace utility
• traces from the EyeSDN USB S0
• IPLog format from the Cisco Secure Intrusion Detection System
• pppd logs (pppdump format)
• the output from VMS’s TCPIPtrace/TCPtrace/UCX$TRACE utilities
• the text output from the DBS Etherwatch VMS utility
• Visual Networks’ Visual UpTime traffic capture
• the output from CoSine L2 debug
• the output from Accellent’s 5Views LAN agents
• Endace Measurement Systems’ ERF format captures
• Linux Bluez Bluetooth stack hcidump -w traces
• Catapult DCT2000 .out files
• Gammu generated text output from Nokia DCT3 phones in Netmonitor mode
• IBM Series (OS/400) Comm traces (ASCII & UNICODE)
• Juniper Netscreen snoop captures
• Symbian OS btsnoop captures
• Tamosoft CommView captures
• Textronix K12xx 32bit .rf5 format captures
• Textronix K12 text file format captures

• Apple PacketLogger captures
• Captures from Aethra Telecommunications’ PC108 software for their test instruments
New file formats are added from time to time.
It may not be possible to read some formats dependent on the packet types captured. Ethernet
captures are usually supported for most file formats but it may not be possible to read other packet
types such as PPP or IEEE 802.11 from all file formats.

Saving captured packets
You can save captured packets simply by using the File › Save As… menu item. You can choose
which packets to save and which file format to be used.
Not all information will be saved in a capture file. For example, most file formats don’t record the
number of dropped packets. See Capture Files for details.

The “Save Capture File As” dialog box
The “Save Capture File As” dialog box allows you to save the current capture to a file. The following
sections show some examples of this dialog box. The appearance of this dialog depends on the
system. However, the functionality should be the same across systems.

Figure 42. “Save” on Microsoft Windows

This is the common Windows file save dialog with some additional Wireshark extensions.
Specific behavior for this dialog:
• If available, the “Help” button will lead you to this section of this “User’s Guide”.
• If you don’t provide a file extension to the filename (e.g. .pcap) Wireshark will append the
standard file extension for that file format.

Figure 43. “Save” on Linux and UNIX

This is the common Gimp/GNOME file save dialog with additional Wireshark extensions.
Specific for this dialog:
• Clicking on the + at “Browse for other folders” will allow you to browse files and folders in your
file system.
With this dialog box, you can perform the following actions:
1. Type in the name of the file you wish to save the captured packets in, as a standard file name in
your file system.
2. Select the directory to save the file into.
3. Select the range of the packets to be saved. See The “Packet Range” frame.

4. Specify the format of the saved capture file by clicking on the File type drop down box. You can
choose from the types described in Output File Formats.
Some capture formats may not be available depending on the packet types captured.
Wireshark can convert file formats

TIP

You can convert capture files from one format to another by reading in a capture file
and writing it out using a different format.

1. Click the [ Save ] or [ OK ] button to accept your selected file and save to it. If Wireshark has a
problem saving the captured packets to the file you specified it will display an error dialog box.
After clicking [ OK ] on that error dialog box you can try again.
2. Click on the [ Cancel ] button to go back to Wireshark without saving any packets.

Output File Formats
Wireshark can save the packet data in its native file format (pcapng) and in the file formats of other
protocol analyzers so other tools can read the capture data.
Different file formats have different time stamp accuracies

WARNING

Saving from the currently used file format to a different format may reduce
the time stamp accuracy; see the Time Stamps for details.

The following file formats can be saved by Wireshark (with the known file extensions):
• pcapng (*.pcapng). A flexible, etensible successor to the libpcap format. Wireshark 1.8 and later
save files as pcapng by default. Versions prior to 1.8 used libpcap.
• libpcap, tcpdump and various other tools using tcpdump’s capture format (*.pcap,*.cap,*.dmp)
• Accellent 5Views (*.5vw)
• HP-UX’s nettl (*.TRC0,*.TRC1)
• Microsoft Network Monitor - NetMon (*.cap)
• Network Associates Sniffer - DOS (*.cap,*.enc,*.trc,*fdc,*.syc)
• Network Associates Sniffer - Windows (*.cap)
• Network Instruments Observer version 9 (*.bfr)
• Novell LANalyzer (*.tr1)
• Oracle (previously Sun) snoop (*.snoop,*.cap)
• Visual Networks Visual UpTime traffic (*.*)
New file formats are added from time to time.
Whether or not the above tools will be more helpful than Wireshark is a different question ;-)

Third party protocol analyzers may require specific file extensions

NOTE

Wireshark examines a file’s contents to determine its type. Some other protocol
analyzers only look at a filename extensions. For example, you might need to use
the .cap extension in order to open a file using Sniffer.

Merging capture files
Sometimes you need to merge several capture files into one. For example, this can be useful if you
have captured simultaneously from multiple interfaces at once (e.g. using multiple instances of
Wireshark).
There are three ways to merge capture files using Wireshark:
• Use the File › Merge menu to open the “Merge” dialog. See The “Merge with Capture File” dialog
box. This menu item will be disabled unless you have loaded a capture file.
• Use drag-and-drop to drop multiple files on the main window. Wireshark will try to merge the
packets in chronological order from the dropped files into a newly created temporary file. If you
drop only a single file it will simply replace the existing capture.
• Use the mergecap tool, a command line tool to merge capture files. This tool provides the most
options to merge capture files. See mergecap: Merging multiple capture files into one for details.

The “Merge with Capture File” dialog box
This dialog box let you select a file to be merged into the currently loaded file. If your current data
has not been saved you will be asked to save it first.
Most controls of this dialog will work the same way as described in the “Open Capture File” dialog
box, see The “Open Capture File” dialog box.
Specific controls of this merge dialog are:
Prepend packets to existing file
Prepend the packets from the selected file before the currently loaded packets.
Merge packets chronologically
Merge both the packets from the selected and currently loaded file in chronological order.
Append packets to existing file
Append the packets from the selected file after the currently loaded packets.

Figure 44. “Merge” on Microsoft Windows

This is the common Windows file open dialog with additional Wireshark extensions.

Figure 45. “Merge” on Linux and UNIX

This is the common Gimp/GNOME file open dialog with additional Wireshark extensions.

Import hex dump
Wireshark can read in an ASCII hex dump and write the data described into a temporary libpcap
capture file. It can read hex dumps with multiple packets in them, and build a capture file of
multiple packets. It is also capable of generating dummy Ethernet, IP and UDP, TCP, or SCTP
headers, in order to build fully processable packet dumps from hexdumps of application-level data
only.
Wireshark understands a hexdump of the form generated by od -Ax -tx1 -v. In other words, each
byte is individually displayed and surrounded with a space. Each line begins with an offset
describing the position in the file. The offset is a hex number (can also be octal or decimal), of more
than two hex digits. Here is a sample dump that can be imported:

000000
000008
000010
000018
000020
000028
000030

00
5a
03
ee
03
16
01

e0
a0
68
33
80
a2
01

1e
b9
00
0f
94
0a
0f

a7
12
00
19
04
00
19

05
08
00
08
00
03
03

6f
00
00
7f
00
50
80

00
46
0a
0f
10
00
11

10
00
2e
19
01
0c
01

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

There is no limit on the width or number of bytes per line. Also the text dump at the end of the line
is ignored. Byte and hex numbers can be uppercase or lowercase. Any text before the offset is
ignored, including email forwarding characters >. Any lines of text between the bytestring lines are
ignored. The offsets are used to track the bytes, so offsets must be correct. Any line which has only
bytes without a leading offset is ignored. An offset is recognized as being a hex number longer than
two characters. Any text after the bytes is ignored (e.g. the character dump). Any hex numbers in
this text are also ignored. An offset of zero is indicative of starting a new packet, so a single text file
with a series of hexdumps can be converted into a packet capture with multiple packets. Packets
may be preceded by a timestamp. These are interpreted according to the format given. If not the
first packet is timestamped with the current time the import takes place. Multiple packets are read
in with timestamps differing by one microsecond each. In general, short of these restrictions,
Wireshark is pretty liberal about reading in hexdumps and has been tested with a variety of
mangled outputs (including being forwarded through email multiple times, with limited line wrap
etc.)
There are a couple of other special features to note. Any line where the first non-whitespace
character is # will be ignored as a comment. Any line beginning with #TEXT2PCAP is a directive and
options can be inserted after this command to be processed by Wireshark. Currently there are no
directives implemented. In the future these may be used to give more fine grained control on the
dump and the way it should be processed e.g. timestamps, encapsulation type etc. Wireshark also
allows the user to read in dumps of application-level data, by inserting dummy L2, L3 and L4
headers before each packet. The user can elect to insert Ethernet headers, Ethernet and IP, or
Ethernet, IP and UDP/TCP/SCTP headers before each packet. This allows Wireshark or any other
full-packet decoder to handle these dumps.

The “Import from Hex Dump” dialog box
This dialog box lets you select a text file, containing a hex dump of packet data, to be imported and
set import parameters.

Figure 46. The “Import from Hex Dump” dialog

Specific controls of this import dialog are split in two sections:
Input
Determine which input file has to be imported and how it is to be interpreted.
Import
Determine how the data is to be imported.
The input parameters are as follows:

Filename / Browse
Enter the name of the text file to import. You can use Browse to browse for a file.
Offsets
Select the radix of the offsets given in the text file to import. This is usually hexadecimal, but
decimal and octal are also supported.
Date/Time
Tick this checkbox if there are timestamps associated with the frames in the text file to import
you would like to use. Otherwise the current time is used for timestamping the frames.
Format
This is the format specifier used to parse the timestamps in the text file to import. It uses a
simple syntax to describe the format of the timestamps, using %H for hours, %M for minutes, %S
for seconds, etc. The straightforward HH:MM:SS format is covered by %T. For a full definition of
the syntax look for strptime(3).
The import parameters are as follows:
Encapsulation type
Here you can select which type of frames you are importing. This all depends on from what type
of medium the dump to import was taken. It lists all types that Wireshark understands, so as to
pass the capture file contents to the right dissector.
Dummy header
When Ethernet encapsulation is selected you have to option to prepend dummy headers to the
frames to import. These headers can provide artificial Ethernet, IP, UDP or TCP or SCTP headers
and SCTP data chunks. When selecting a type of dummy header the applicable entries are
enabled, others are grayed out and default values are used.
Maximum frame length
You may not be interested in the full frames from the text file, just the first part. Here you can
define how much data from the start of the frame you want to import. If you leave this open the
maximum is set to 65535 bytes.
Once all input and import parameters are setup click [ OK ] to start the import. If your current data
wasn’t saved before you will be asked to save it first.
When completed there will be a new capture file loaded with the frames imported from the text
file.

File Sets
When using the “Multiple Files” option while doing a capture (see: Capture files and file modes), the
capture data is spread over several capture files, called a file set.

As it can become tedious to work with a file set by hand, Wireshark provides some features to
handle these file sets in a convenient way.

How does Wireshark detect the files of a file set?
A filename in a file set uses the format Prefix_Number_DateTimeSuffix which might look
something like test_00001_20060420183910.pcap. All files of a file set share the same prefix (e.g.
“test”) and suffix (e.g. “.pcap”) and a varying middle part.
To find the files of a file set, Wireshark scans the directory where the currently loaded file
resides and checks for files matching the filename pattern (prefix and suffix) of the currently
loaded file.
This simple mechanism usually works well but has its drawbacks. If several file sets were
captured with the same prefix and suffix, Wireshark will detect them as a single file set. If
files were renamed or spread over several directories the mechanism will fail to find all files
of a set.
The following features in the File › File Set submenu are available to work with file sets in a
convenient way:
• The “List Files” dialog box will list the files Wireshark has recognized as being part of the
current file set.
• [ Next File ] closes the current and opens the next file in the file set.
• [ Previous File ] closes the current and opens the previous file in the file set.

The “List Files” dialog box

Figure 47. The “List Files” dialog box

Each line contains information about a file of the file set:
• Filename the name of the file. If you click on the filename (or the radio button left to it), the
current file will be closed and the corresponding capture file will be opened.
• Created the creation time of the file
• Last Modified the last time the file was modified
• Size the size of the file
The last line will contain info about the currently used directory where all of the files in the file set
can be found.
The content of this dialog box is updated each time a capture file is opened/closed.
The [ Close ] button will, well, close the dialog box.

Exporting data
Wireshark provides several ways and formats to export packet data. This section describes general
ways to export data from the main Wireshark application. There are more specialized functions to
export specific data which are described elsewhere.

The “Export as Plain Text File” dialog box
Export packet data into a plain ASCII text file, much like the format used to print packets.
If you would like to be able to import any previously exported packets from a plain
text file it is recommended that you:
• Add the “Absolute date and time” column.
• Temporarily hide all other columns.
TIP

• Disable the Edit › Preferences › Protocols › Data “Show not dissected data on new
Packet Bytes pane” preference. More details are provided in Preferences
• Include the packet summary line.
• Exclude column headings.
• Exclude packet details.
• Include the packet bytes.

Figure 48. The “Export as Plain Text File” dialog box

• The “Export to file:” frame chooses the file to export the packet data to.
• The “Packet Range” frame is described in The “Packet Range” frame.
• The “Packet Details” frame is described in The Packet Format frame.

The “Export as PostScript File” dialog box

Figure 49. The “Export as PostScript File” dialog box

• Export to file: frame chooses the file to export the packet data to.
• The Packet Range frame is described in The “Packet Range” frame.
• The Packet Details frame is described in The Packet Format frame.

The “Export as CSV (Comma Separated Values) File” dialog box
Export packet summary into CSV, used e.g. by spreadsheet programs to im-/export data.
• Export to file: frame chooses the file to export the packet data to.
• The Packet Range frame is described in The “Packet Range” frame.

The “Export as C Arrays (packet bytes) file” dialog box
Export packet bytes into C arrays so you can import the stream data into your own C program.
• Export to file: frame chooses the file to export the packet data to.
• The Packet Range frame is described in The “Packet Range” frame.

The “Export as PSML File” dialog box
Export packet data into PSML. This is an XML based format including only the packet summary. The
PSML file specification is available at: http://www.nbee.org/doku.php?id=netpdl:psml_specification.

Figure 50. The “Export as PSML File” dialog box

• Export to file: frame chooses the file to export the packet data to.
• The Packet Range frame is described in The “Packet Range” frame.
There’s no such thing as a packet details frame for PSML export, as the packet format is defined by
the PSML specification.

The “Export as PDML File” dialog box
Export packet data into PDML. This is an XML based format including the packet details. The PDML
file specification is available at: http://www.nbee.org/doku.php?id=netpdl:pdml_specification.

The PDML specification is not officially released and Wireshark’s implementation of
NOTE

it is still in an early beta state, so please expect changes in future Wireshark
versions.

Figure 51. The “Export as PDML File” dialog box

• Export to file: frame chooses the file to export the packet data to.
• The Packet Range frame is described in The “Packet Range” frame.
There’s no such thing as a packet details frame for PDML export, as the packet format is defined by
the PDML specification.

The “Export selected packet bytes” dialog box
Export the bytes selected in the “Packet Bytes” pane into a raw binary file.

Figure 52. The “Export Selected Packet Bytes” dialog box

• Name: the filename to export the packet data to.
• The Save in folder: field lets you select the folder to save to (from some predefined folders).
• Browse for other folders provides a flexible way to choose a folder.

The “Export Objects” dialog box
This feature scans through the selected protocol’s streams in the currently open capture file or
running capture and allows the user to export reassembled objects to the disk. For example, if you
select HTTP, you can export HTML documents, images, executables, and any other files transferred
over HTTP to the disk. If you have a capture running, this list is automatically updated every few
seconds with any new objects seen. The saved objects can then be opened or examined
independently of Wireshark.

Figure 53. The “Export Objects” dialog box

Columns:
• Packet: The packet number in which this object was found. In some cases, there can be multiple
objects in the same packet.
• Hostname: The hostname of the server that sent this object.
• Content Type: The content type of this object.
• Size: The size of this object in bytes.
• Filename: The filename for this object. Each protocol generates the filename differently. For
example, HTTP uses the final part of the URI and IMF uses the subject of the email.
Buttons:
• Help: Opens the “Export Objects” section in the user’s guide.
• Save All: Saves all objects in the list using the filename from the filename column. You will be
asked what directory / folder to save them in.
• Close: Closes the “Export Objects” dialog.
• Save: Saves the currently selected object as a filename you specify. The default filename to save
as is taken from the filename column of the objects list.

Printing packets
To print packets, select the File › Print… menu item. When you do this Wireshark pops up the
“Print” dialog box as shown in The “Print” dialog box.

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The “Print” dialog box

Figure 54. The “Print” dialog box

The following fields are available in the Print dialog box: Printer
This field contains a pair of mutually exclusive radio buttons:
• Plain Text specifies that the packet print should be in plain text.
• PostScript specifies that the packet print process should use PostScript to generate a better
print output on PostScript aware printers.
• Output to file: specifies that printing be done to a file, using the filename entered in the field
or selected with the browse button.
This field is where you enter the file to print to if you have selected Print to a file, or you can
click the button to browse the filesystem. It is greyed out if Print to a file is not selected.
• Print command specifies that a command be used for printing.

NOTE

Note!

These Print command fields are not available on windows platforms.

This field specifies the command to use for printing. It is typically lpr. You would change it to

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specify a particular queue if you need to print to a queue other than the default. An example
might be:

$ lpr -Pmypostscript
This field is greyed out if Output to file: is checked above.
Packet Range
Select the packets to be printed, see The “Packet Range” frame
Packet Format
Select the output format of the packets to be printed. You can choose, how each packet is printed,
see The “Packet Format” frame

The “Packet Range” frame
The packet range frame is a part of various output related dialog boxes. It provides options to select
which packets should be processed by the output function.

Figure 55. The “Packet Range” frame

If the [ Captured ] button is set (default), all packets from the selected rule will be processed. If the
[ Displayed ] button is set, only the currently displayed packets are taken into account to the
selected rule.
• All packets will process all packets.
• Selected packet only process only the selected packet.
• Marked packets only process only the marked packets.
• From first to last marked packet process the packets from the first to the last marked one.

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• Specify a packet range process a user specified range of packets, e.g. specifying 5,10-15,20- will
process the packet number five, the packets from packet number ten to fifteen (inclusive) and
every packet from number twenty to the end of the capture.

The Packet Format frame
The packet format frame is a part of various output related dialog boxes. It provides options to
select which parts of a packet should be used for the output function.

Figure 56. The “Packet Format” frame

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• Packet summary line enable the output of the summary line, just as in the “Packet List” pane.
• Packet details enable the output of the packet details tree.
• All collapsed the info from the “Packet Details” pane in “all collapsed” state.
• As displayed the info from the “Packet Details” pane in the current state.
• All expanded the info from the “Packet Details” pane in “all expanded” state.
• Packet bytes enable the output of the packet bytes, just as in the “Packet Bytes” pane.
• Each packet on a new page put each packet on a separate page (e.g. when saving/printing to a
text file, this will put a form feed character between the packets).

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Working with captured packets
Viewing packets you have captured
Once you have captured some packets or you have opened a previously saved capture file, you can
view the packets that are displayed in the packet list pane by simply clicking on a packet in the
packet list pane, which will bring up the selected packet in the tree view and byte view panes.
You can then expand any part of the tree to view detailed information about each protocol in each
packet. Clicking on an item in the tree will highlight the corresponding bytes in the byte view. An
example with a TCP packet selected is shown in Wireshark with a TCP packet selected for viewing.
It also has the Acknowledgment number in the TCP header selected, which shows up in the byte
view as the selected bytes.

Figure 57. Wireshark with a TCP packet selected for viewing

You can also select and view packets the same way while Wireshark is capturing if you selected
“Update list of packets in real time” in the “Capture Preferences” dialog box.
In addition you can view individual packets in a separate window as shown in Viewing a packet in
a separate window. You can do this by double-clicking on an item in the packet list or by selecting
the packet in which you are interested in the packet list pane and selecting View › Show Packet in
New Window. This allows you to easily compare two or more packets, even across multiple files.

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Figure 58. Viewing a packet in a separate window

Along with double-clicking the packet list and using the main menu there are a number of other
ways to open a new packet window:
• Hold down the shift key and double-click on a frame link in the packet details.
• From The menu items of the “Packet List” pop-up menu.
• From The menu items of the “Packet Details” pop-up menu.

Pop-up menus
You can bring up a pop-up menu over either the “Packet List”, its column header, or “Packet
Details” pane by clicking your right mouse button at the corresponding pane.

Pop-up menu of the “Packet List” column header

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Figure 59. Pop-up menu of the “Packet List” column header

The following table gives an overview of which functions are available in this header, where to find
the corresponding function in the main menu, and a short description of each item.
Table 17. The menu items of the “Packet List” column header pop-up menu

Item

Identical to main Description
menu’s item:

Sort Ascending

Sort the packet list in ascending order based on
this column.

Sort Descending

Sort the packet list in descending order based on
this column.

No Sort

Remove sorting order based on this column.

Align Left

Set left alignment of the values in this column.

Align Center

Set center alignment of the values in this
column.

Align Right

Set right alignment of the values in this column.

Column Preferences…

Open the Preferences dialog box on the column
tab.

Resize Column

Resize the column to fit the values.

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Item

Identical to main Description
menu’s item:

Rename Column Title
Displayed Column

Allows you to change the title of the column
header.
View

This menu items folds out with a list of all
configured columns. These columns can now be
shown or hidden in the packet list.

Hide Column

Allows you to hide the column from the packet
list.

Remove Column

Allows you to remove the column from the
packet list.

Pop-up menu of the “Packet List” pane

Figure 60. Pop-up menu of the “Packet List” pane

The following table gives an overview of which functions are available in this pane, where to find
the corresponding function in the main menu, and a short description of each item.
Table 18. The menu items of the “Packet List” pop-up menu

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Item

Identical to main Description
menu’s item:

Mark Packet (toggle)

Edit

Mark/unmark a packet.

Ignore Packet (toggle)

Edit

Ignore or inspect this packet while dissecting the
capture file.

Set Time Reference
(toggle)

Edit

Set/reset a time reference.

Manually Resolve Address

Allows you to enter a name to resolve for the
selected address.

Apply as Filter

Analyze

Prepare and apply a display filter based on the
currently selected item.

Prepare a Filter

Analyze

Prepare a display filter based on the currently
selected item.

Conversation Filter

This menu item applies a display filter with the
address information from the selected packet.
E.g. the IP menu entry will set a filter to show
the traffic between the two IP addresses of the
current packet. XXX - add a new section
describing this better.

Colorize Conversation

This menu item uses a display filter with the
address information from the selected packet to
build a new colorizing rule.

SCTP

Allows you to analyze and prepare a filter for
this SCTP association.

Follow TCP Stream

Analyze

Allows you to view all the data on a TCP stream
between a pair of nodes.

Follow UDP Stream

Analyze

Allows you to view all the data on a UDP
datagram stream between a pair of nodes.

Follow SSL Stream

Analyze

Same as “Follow TCP Stream” but for SSL. XXX add a new section describing this better.

Copy/ Summary (Text)

Copy the summary fields as displayed to the
clipboard, as tab-separated text.

Copy/ Summary (CSV)

Copy the summary fields as displayed to the
clipboard, as comma-separated text.

Copy/ As Filter

Prepare a display filter based on the currently
selected item and copy that filter to the
clipboard.

Copy/ Bytes (Offset Hex
Text)

Copy the packet bytes to the clipboard in
hexdump-like format.

Copy/ Bytes (Offset Hex)

Copy the packet bytes to the clipboard in
hexdump-like format, but without the text
portion.

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Item

Identical to main Description
menu’s item:

Copy/ Bytes (Printable Text
Only)

Copy the packet bytes to the clipboard as ASCII
text, excluding non-printable characters.

Copy/ Bytes (Hex Stream)

Copy the packet bytes to the clipboard as an
unpunctuated list of hex digits.

Copy/ Bytes (Binary
Stream)

Copy the packet bytes to the clipboard as raw
binary. The data is stored in the clipboard as
MIME-type “application/octet-stream”.

Decode As…

Analyze

Change or apply a new relation between two
dissectors.

Print…

File

Print packets.

Show Packet in New
Window

View

Display the selected packet in a new window.

Pop-up menu of the “Packet Details” pane

Figure 61. Pop-up menu of the “Packet Details” pane

The following table gives an overview of which functions are available in this pane, where to find
the corresponding function in the main menu, and a short description of each item.

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Table 19. The menu items of the “Packet Details” pop-up menu

Item

Identical to main Description
menu’s item:

Expand Subtrees

View

Expand the currently selected subtree.

Collapse Subtrees

View

Collapse the currently selected subtree.

Expand All

View

Expand all subtrees in all packets in the capture.

Collapse All

View

Wireshark keeps a list of all the protocol
subtrees that are expanded, and uses it to
ensure that the correct subtrees are expanded
when you display a packet. This menu item
collapses the tree view of all packets in the
capture list.

Apply as Column

Use the selected protocol item to create a new
column in the packet list.

Apply as Filter

Analyze

Prepare and apply a display filter based on the
currently selected item.

Prepare a Filter

Analyze

Prepare a display filter based on the currently
selected item.

Colorize with Filter

This menu item uses a display filter with the
information from the selected protocol item to
build a new colorizing rule.

Follow TCP Stream

Analyze

Allows you to view all the data on a TCP stream
between a pair of nodes.

Follow UDP Stream

Analyze

Allows you to view all the data on a UDP
datagram stream between a pair of nodes.

Follow SSL Stream

Analyze

Same as “Follow TCP Stream” but for SSL. XXX add a new section describing this better.

Copy/ Description

Edit

Copy the displayed text of the selected field to
the system clipboard.

Copy/ Fieldname

Edit

Copy the name of the selected field to the system
clipboard.

Copy/ Value

Edit

Copy the value of the selected field to the system
clipboard.

Copy/ As Filter

Edit

Prepare a display filter based on the currently
selected item and copy it to the clipboard.

Copy/ Bytes (Offset Hex
Text)

Copy the packet bytes to the clipboard in
hexdump-like format; similar to the Packet List
Pane command, but copies only the bytes
relevant to the selected part of the tree (the
bytes selected in the Packet Bytes Pane).

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Item

Identical to main Description
menu’s item:

Copy/ Bytes (Offset Hex)

Copy the packet bytes to the clipboard in
hexdump-like format, but without the text
portion; similar to the Packet List Pane
command, but copies only the bytes relevant to
the selected part of the tree (the bytes selected in
the Packet Bytes Pane).

Copy/ Bytes (Printable Text
Only)

Copy the packet bytes to the clipboard as ASCII
text, excluding non-printable characters; similar
to the Packet List Pane command, but copies
only the bytes relevant to the selected part of the
tree (the bytes selected in the Packet Bytes Pane).

Copy/ Bytes (Hex Stream)

Copy the packet bytes to the clipboard as an
unpunctuated list of hex digits; similar to the
Packet List Pane command, but copies only the
bytes relevant to the selected part of the tree
(the bytes selected in the Packet Bytes Pane).

Copy/ Bytes (Binary
Stream)

Copy the packet bytes to the clipboard as raw
binary; similar to the Packet List Pane
command, but copies only the bytes relevant to
the selected part of the tree (the bytes selected in
the Packet Bytes Pane). The data is stored in the
clipboard as MIME-type “application/octetstream”.

Export Selected Packet
Bytes…

File

This menu item is the same as the File menu
item of the same name. It allows you to export
raw packet bytes to a binary file.

Wiki Protocol Page

Show the wiki page corresponding to the
currently selected protocol in your web browser.

Filter Field Reference

Show the filter field reference web page
corresponding to the currently selected protocol
in your web browser.

Protocol Preferences…

The menu item takes you to the properties
dialog and selects the page corresponding to the
protocol if there are properties associated with
the highlighted field. More information on
preferences can be found in The preferences
dialog box.

Decode As…
Disable Protocol

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Analyze

Change or apply a new relation between two
dissectors.
Allows you to temporarily disable a protocol
dissector, which may be blocking the legitimate
dissector.

Item

Identical to main Description
menu’s item:

Resolve Name

View

Causes a name resolution to be performed for
the selected packet, but NOT every packet in the
capture.

Go to Corresponding
Packet

If the selected field has a corresponding packet,
go to it. Corresponding packets will usually be a
request/response packet pair or such.

Filtering packets while viewing
Wireshark has two filtering languages: One used when capturing packets, and one used when
displaying packets. In this section we explore that second type of filter: Display filters. The first one
has already been dealt with in Filtering while capturing.
Display filters allow you to concentrate on the packets you are interested in while hiding the
currently uninteresting ones. They allow you to select packets by:
• Protocol
• The presence of a field
• The values of fields
• A comparison between fields
• … and a lot more!
To select packets based on protocol type, simply type the protocol in which you are interested in the
Filter: field in the filter toolbar of the Wireshark window and press enter to initiate the filter.
Filtering on the TCP protocol shows an example of what happens when you type tcp in the filter
field.
NOTE

All protocol and field names are entered in lowercase. Also, don’t forget to press
enter after entering the filter expression.

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Figure 62. Filtering on the TCP protocol

As you might have noticed, only packets of the TCP protocol are displayed now (e.g. packets 1-10 are
hidden). The packet numbering will remain as before, so the first packet shown is now packet
number 11.
NOTE

When using a display filter, all packets remain in the capture file. The display filter
only changes the display of the capture file but not its content!

You can filter on any protocol that Wireshark understands. You can also filter on any field that a
dissector adds to the tree view, but only if the dissector has added an abbreviation for the field. A
list of such fields is available in Wireshark in the Add Expression… dialog box. You can find more
information on the Add Expression… dialog box in The “Filter Expression” dialog box.
For example, to narrow the packet list pane down to only those packets to or from the IP address
192.168.0.1, use ip.addr==192.168.0.1.
NOTE

To remove the filter, click on the [ Clear ] button to the right of the filter field.

Building display filter expressions
Wireshark provides a simple but powerful display filter language that allows you to build quite
complex filter expressions. You can compare values in packets as well as combine expressions into

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more specific expressions. The following sections provide more information on doing this.
TIP

You will find a lot of Display Filter examples at the Wireshark Wiki Display Filter page
at: https://wiki.wireshark.org/DisplayFilters.

Display filter fields
Every field in the packet details pane can be used as a filter string, this will result in showing only
the packets where this field exists. For example: the filter string: tcp will show all packets
containing the tcp protocol.
There is a complete list of all filter fields available through the menu item Help › Supported
Protocols in the page “Display Filter Fields” of the “Supported Protocols” dialog.

Comparing values
You can build display filters that compare values using a number of different comparison
operators. They are shown in Display Filter comparison operators.
TIP

You can use English and C-like terms in the same way, they can even be mixed in a
filter string.

Table 20. Display Filter comparison operators

English

C-like

Description and example

Equal. ip.src==10.0.0.5

Not equal. ip.src!=10.0.0.5

Greater than. frame.len > 10

Less than. frame.len < 128

Greater than or equal to. frame.len ge 0x100

Less than or equal to. frame.len <= 0x20

contains

Protocol, field or slice contains a value. sip.To contains "a1762"

matches

Protocol or text field match Perl regualar expression. http.host
matches "acme\.(org|com|net)"

bitwise_and

Compare bit field value. tcp.flags & 0x02

In addition, all protocol fields have a type. Display Filter Field Types provides a list of the types and
example of how to express them.
Display Filter Field Types

Unsigned integer
Can be 8, 16, 24, 32, or 64 bits. You can express integers in decimal, octal, or hexadecimal. The
following display filters are equivalent:

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ip.len le 1500

ip.len le 02734

ip.len le 0x5dc
Signed integer
Can be 8, 16, 24, 32, or 64 bits. As with unsigned integers you can use decimal, octal, or
hexadecimal.
Boolean
A boolean field is present in the protocol decode only if its value is true. For example,
tcp.flags.syn is present, and thus true, only if the SYN flag is present in a TCP segment header.

The filter expression `tcp.flags.syn` will select only those packets for which
this flag exists, that is, TCP segments where the segment header contains the
SYN flag. Similarly, to find source-routed token ring packets, use a filter
expression of `tr.sr`.
Ethernet address
6 bytes separated by a colon (:), dot (.) or dash (-) with one or two bytes between separators:

eth.dst == ff:ff:ff:ff:ff:ff

eth.dst == ff-ff-ff-ff-ff-ff

eth.dst == ffff.ffff.ffff
IPv4 address
ip.addr == 192.168.0.1

Classless InterDomain Routing (CIDR) notation can be used to test if
an IPv4 address is in a certain subnet. For example, this display
filter will find all packets in the 129.111 Class-B network:

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ip.addr == 129.111.0.0/16
IPv6 address
ipv6.addr == ::1

As with IPv4 addresses, IPv6 addresses can match a subnet.
Text string
http.request.uri == "https://www.wireshark.org/"

udp contains 81:60:03
The example above match packets that contains the 3-byte sequence 0x81, 0x60, 0x03 anywhere in
the UDP header or payload.

sip.To contains "a1762"
Above example match packets where SIP To-header contains the string "a1762" anywhere in the
header.

http.host matches "acme\.(org|com|net)"
The example above match HTTP packets where the HOST header contains acme.org or acme.com or
acme.net. Comparisons are case-insensitive. Note: Wireshark needs to be built with libpcre in order
to be able to use the matches resp. {tilde} operator.

tcp.flags & 0x02
That expression will match all packets that contain a “tcp.flags” field with the 0x02 bit, i.e. the SYN
bit, set.

Combining expressions
You can combine filter expressions in Wireshark using the logical operators shown in Display Filter
Logical Operations
Table 21. Display Filter Logical Operations

English

C-like

Description and example

and

Logical AND. ip.src==10.0.0.5 and tcp.flags.fin

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English

C-like

Description and example

Logical OR. ip.scr==10.0.0.5 or ip.src==192.1.1.1

xor

Logical XOR. tr.dst[0:3] == 0.6.29 xor tr.src[0:3] == 0.6.29

not

Logical NOT. not llc

[…]

See “Slice Operator” below.

See “Membership Operator” below.

Slice Operator
Wireshark allows you to select subsequences of a sequence in rather elaborate ways. After a label
you can place a pair of brackets [] containing a comma separated list of range specifiers.

eth.src[0:3] == 00:00:83
The example above uses the n:m format to specify a single range. In this case n is the beginning
offset and m is the length of the range being specified.

eth.src[1-2] == 00:83
The example above uses the n-m format to specify a single range. In this case n is the beginning
offset and m is the ending offset.

eth.src[:4] == 00:00:83:00
The example above uses the :m format, which takes everything from the beginning of a sequence to
offset m. It is equivalent to 0:m

eth.src[4:] == 20:20
The example above uses the n: format, which takes everything from offset n to the end of the
sequence.

eth.src[2] == 83
The example above uses the n format to specify a single range. In this case the element in the
sequence at offset n is selected. This is equivalent to n:1.

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eth.src[0:3,1-2,:4,4:,2] ==
00:00:83:00:83:00:00:83:00:20:20:83
Wireshark allows you to string together single ranges in a comma separated list to form compound
ranges as shown above.

Membership Operator
Wireshark allows you to test a field for membership in a set of values or fields. After the field name,
use the in operator followed by the set items surrounded by braces {}.

tcp.port in {80 443 8080}
This can be considered a shortcut operator, as the previous expression could have been expressed
as:

tcp.port == 80 || tcp.port == 443 || tcp.port == 8080
The set of values can also contain ranges:

tcp.port in {443 4430..4434}
This is not merely a shortcut for tcp.port == 443 || (tcp.port >= 4430 && tcp.port <= 4434).
Comparison operators are usually satisfied when any field matches the filter, and thus a packet
with ports 80 and 56789 would match this alternative display filter since 56789 >= 4430 && 80 <=
4434 is true. The membership operator instead tests the same field against the range condition.
Sets are not just limited to numbers, other types can be used as well:

http.request.method in {"HEAD" "GET"}
ip.addr in {10.0.0.5 .. 10.0.0.9 192.168.1.1..192.168.1.9}
frame.time_delta in {10 .. 10.5}

Functions
The display filter language has a number of functions to convert fields, see Display Filter Functions.
Table 22. Display Filter Functions

Function

Description

upper

Converts a string field to uppercase.

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Function

Description

lower

Converts a string field to lowercase.

len

Returns the byte length of a string or bytes field.

count

Returns the number of field occurrences in a frame.

The upper and lower functions can used to force case-insensitive matches: lower(http.server)
contains "apache".
To find HTTP requests with long request URIs: len(http.request.uri) > 100. Note that the len
function yields the string length in bytes rather than (multi-byte) characters.
Usually an IP frame has only two addresses (source and destination), but in case of ICMP errors or
tunneling, a single packet might contain even more addresses. These packets can be found with
count(ip.addr) > 2.

A Common Mistake
Using the != operator on combined expressions like eth.addr, ip.addr, tcp.port, and udp.port will
probably not work as expected.
Often people use a filter string to display something like ip.addr == 1.2.3.4 which will display all
packets containing the IP address 1.2.3.4.
Then they use ip.addr != 1.2.3.4 to see all packets not containing the IP address 1.2.3.4 in it.
Unfortunately, this does not do the expected.
Instead, that expression will even be true for packets where either source or destination IP address
equals 1.2.3.4. The reason for this, is that the expression ip.addr != 1.2.3.4 must be read as “the
packet contains a field named ip.addr with a value different from 1.2.3.4”. As an IP datagram
contains both a source and a destination address, the expression will evaluate to true whenever at
least one of the two addresses differs from 1.2.3.4.
If you want to filter out all packets containing IP datagrams to or from IP address 1.2.3.4, then the
correct filter is !(ip.addr == 1.2.3.4) as it reads “show me all the packets for which it is not true
that a field named ip.addr exists with a value of 1.2.3.4”, or in other words, “filter out all packets for
which there are no occurrences of a field named ip.addr with the value 1.2.3.4”.

The “Filter Expression” dialog box
When you are accustomed to Wireshark’s filtering system and know what labels you wish to use in
your filters it can be very quick to simply type a filter string. However if you are new to Wireshark
or are working with a slightly unfamiliar protocol it can be very confusing to try to figure out what
to type. The “Filter Expression” dialog box helps with this.

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TIP

The “Filter Expression” dialog box is an excellent way to learn how to write Wireshark
display filter strings.

Figure 63. The “Filter Expression” dialog box

When you first bring up the Filter Expression dialog box you are shown a tree of field names,
organized by protocol, and a box for selecting a relation.
Field Name
Select a protocol field from the protocol field tree. Every protocol with filterable fields is listed at
the top level. (You can search for a particular protocol entry by entering the first few letters of
the protocol name). By expanding a protocol name you can get a list of the field names available
for filtering for that protocol.
Relation
Select a relation from the list of available relation. The is present is a unary relation which is
true if the selected field is present in a packet. All other listed relations are binary relations
which require additional data (e.g. a Value to match) to complete.
When you select a field from the field name list and select a binary relation (such as the equality
relation ==) you will be given the opportunity to enter a value, and possibly some range
information.
Value
You may enter an appropriate value in the Value text box. The Value will also indicate the type of
value for the field name you have selected (like character string).

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Predefined values
Some of the protocol fields have predefined values available, much like enum’s in C. If the
selected protocol field has such values defined, you can choose one of them here.
Range
A range of integers or a group of ranges, such as 1-12 or 39-42,98-2000.
OK
When you have built a satisfactory expression click [ OK ] and a filter string will be built for you.
Cancel
You can leave the “Add Expression…” dialog box without any effect by clicking the [ Cancel ]
button.

Defining and saving filters
You can define filters with Wireshark and give them labels for later use. This can save time in
remembering and retyping some of the more complex filters you use.
To define a new filter or edit an existing one, select Capture › Capture Filters… or Analyze ›
Display Filters…. Wireshark will then pop up the Filters dialog as shown in The “Capture Filters”
and “Display Filters” dialog boxes.
The mechanisms for defining and saving capture filters and display filters are almost identical.
Both will be described here but the differences between these two will be marked as such.
WARNING

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You must use [ Save ] to save your filters permanently. [ OK ] or [ Apply ] will
not save the filters and they will be lost when you close Wireshark.

Figure 64. The “Capture Filters” and “Display Filters” dialog boxes

New
This button adds a new filter to the list of filters. The currently entered values from Filter name
and Filter string will be used. If any of these fields are empty, it will be set to “new”.
Delete
This button deletes the selected filter. It will be greyed out, if no filter is selected.
Filter
You can select a filter from this list (which will fill in the filter name and filter string in the fields
down at the bottom of the dialog box).
Filter name:
You can change the name of the currently selected filter here.
The filter name will only be used in this dialog to identify the filter for your convenience, it will
not be used elsewhere. You can add multiple filters with the same name, but this is not very
useful.

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Filter string:
You can change the filter string of the currently selected filter here. Display Filter only: the string
will be syntax checked while you are typing.
Add Expression…
Display Filter only: This button brings up the Add Expression dialog box which assists in
building filter strings. You can find more information about the Add Expression dialog in The
“Filter Expression” dialog box
OK
Display Filter only: This button applies the selected filter to the current display and closes the
dialog.
Apply
Display Filter only: This button applies the selected filter to the current display, and keeps the
dialog open.
Save
Save the current settings in this dialog. The file location and format is explained in Files and
Folders.
Close
Close this dialog. This will discard unsaved settings.

Defining and saving filter macros
You can define filter macros with Wireshark and give them labels for later use. This can save time
in remembering and retyping some of the more complex filters you use.

Finding packets
You can easily find packets once you have captured some packets or have read in a previously
saved capture file. Simply select the Find Packet… menu item from the Edit menu. Wireshark will
pop up the dialog box shown in The “Find Packet” dialog box.

The “Find Packet” dialog box

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Figure 65. The “Find Packet” dialog box

You might first select the kind of thing to search for:
• Display filter
Simply enter a display filter string into the Filter: field, select a direction, and click on OK.
For example, to find the three way handshake for a connection from host 192.168.0.1, use the
following filter string:

ip.src==192.168.0.1 and tcp.flags.syn==1
For more details on display filters, see Filtering packets while viewing
• Hex Value
Search for a specific byte sequence in the packet data.
For example, use “00:00” to find the next packet including two null bytes in the packet data.
• String
Find a string in the packet data, with various options.
The value to be found will be syntax checked while you type it in. If the syntax check of your
value succeeds, the background of the entry field will turn green, if it fails, it will turn red.

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You can choose the search direction:
• Up
Search upwards in the packet list (decreasing packet numbers).
• Down
Search downwards in the packet list (increasing packet numbers).

The “Find Next” command
“Find Next” will continue searching with the same options used in the last “Find Packet”.

The “Find Previous” command
“Find Previous” will do the same thing as “Find Next”, but in the reverse direction.

Go to a specific packet
You can easily jump to specific packets with one of the menu items in the Go menu.

The “Go Back” command
Go back in the packet history, works much like the page history in current web browsers.

The “Go Forward” command
Go forward in the packet history, works much like the page history in current web browsers.

The “Go to Packet” dialog box

Figure 66. The “Go To Packet” dialog box

This dialog box will let you enter a packet number. When you press [ OK ], Wireshark will jump to
that packet.

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The “Go to Corresponding Packet” command
If a protocol field is selected which points to another packet in the capture file, this command will
jump to that packet.
As these protocol fields now work like links (just as in your Web browser), it’s easier to simply
double-click on the field to jump to the corresponding field.

The “Go to First Packet” command
This command will simply jump to the first packet displayed.

The “Go to Last Packet” command
This command will simply jump to the last packet displayed.

Marking packets
You can mark packets in the “Packet List” pane. A marked packet will be shown with black
background, regardless of the coloring rules set. Marking a packet can be useful to find it later
while analyzing in a large capture file.
The packet marks are not stored in the capture file or anywhere else. All packet marks will be lost
when you close the capture file.
You can use packet marking to control the output of packets when saving, exporting, or printing. To
do so, an option in the packet range is available, see The “Packet Range” frame.
There are three functions to manipulate the marked state of a packet:
• Mark packet (toggle) toggles the marked state of a single packet.
• Mark all displayed packets set the mark state of all displayed packets.
• Unmark all packets reset the mark state of all packets.
These mark functions are available from the “Edit” menu, and the “Mark packet (toggle)” function
is also available from the pop-up menu of the “Packet List” pane.

Ignoring packets
You can ignore packets in the “Packet List” pane. Wireshark will then pretend that this packets does
not exist in the capture file. An ignored packet will be shown with white background and gray
foreground, regardless of the coloring rules set.
The packet ignored marks are not stored in the capture file or anywhere else. All “packet ignored”
marks will be lost when you close the capture file.

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There are three functions to manipulate the ignored state of a packet:
• Ignore packet (toggle) toggles the ignored state of a single packet.
• Ignore all displayed packets set the ignored state of all displayed packets.
• Un-Ignore all packets reset the ignored state of all packets.
These ignore functions are available from the “Edit” menu, and the “Ignore packet (toggle)”
function is also available from the pop-up menu of the “Packet List” pane.

Time display formats and time references
While packets are captured, each packet is timestamped. These timestamps will be saved to the
capture file, so they will be available for later analysis.
A detailed description of timestamps, timezones and alike can be found at: Time Stamps.
The timestamp presentation format and the precision in the packet list can be chosen using the
View menu, see The “View” Menu.
The available presentation formats are:
• Date and Time of Day: 1970-01-01 01:02:03.123456 The absolute date and time of the day when
the packet was captured.
• Time of Day: 01:02:03.123456 The absolute time of the day when the packet was captured.
• Seconds Since Beginning of Capture: 123.123456 The time relative to the start of the capture file
or the first “Time Reference” before this packet (see Packet time referencing).
• Seconds Since Previous Captured Packet: 1.123456 The time relative to the previous captured
packet.
• Seconds Since Previous Displayed Packet: 1.123456 The time relative to the previous displayed
packet.
• Seconds Since Epoch (1970-01-01): 1234567890.123456 The time relative to epoch (midnight UTC
of January 1, 1970).
The available precisions (aka. the number of displayed decimal places) are:
• Automatic The timestamp precision of the loaded capture file format will be used (the default).
• Seconds, Deciseconds, Centiseconds, Milliseconds, Microseconds or Nanoseconds The timestamp
precision will be forced to the given setting. If the actually available precision is smaller, zeros
will be appended. If the precision is larger, the remaining decimal places will be cut off.
Precision example: If you have a timestamp and it’s displayed using, “Seconds Since Previous
Packet” the value might be 1.123456. This will be displayed using the “Automatic” setting for
libpcap files (which is microseconds). If you use Seconds it would show simply 1 and if you use

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Nanoseconds it shows 1.123456000.

Packet time referencing
The user can set time references to packets. A time reference is the starting point for all subsequent
packet time calculations. It will be useful, if you want to see the time values relative to a special
packet, e.g. the start of a new request. It’s possible to set multiple time references in the capture file.
The time references will not be saved permanently and will be lost when you close the capture file.
Time referencing will only be useful if the time display format is set to “Seconds Since Beginning of
Capture”. If one of the other time display formats are used, time referencing will have no effect
(and will make no sense either).
To work with time references, choose one of the Time Reference › ] items in the menu:[Edit
menu or from the pop-up menu of the “Packet List” pane. See The “Edit” Menu.
• Set Time Reference (toggle) Toggles the time reference state of the currently selected packet to on
or off.
• Find Next Find the next time referenced packet in the “Packet List” pane.
• Find Previous Find the previous time referenced packet in the “Packet List” pane.

Figure 67. Wireshark showing a time referenced packet

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A time referenced packet will be marked with the string *REF* in the Time column (see packet
number 10). All subsequent packets will show the time since the last time reference.

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Advanced Topics
Introduction
This chapter some of Wireshark’s advanced features.

Following Protocol Streams
It can be very helpful to see protocol in the way that the application layer sees it. Perhaps you are
looking for passwords in a Telnet stream, or you are trying to make sense of a data stream. Maybe
you just need a display filter to show only the packets in an SSL stream. If so, Wireshark’s ability to
follow protocol streams will be useful to you.
Simply select a TCP, UDP, SSL, or HTTP packet in the packet list of the stream/connection you are
interested in and then select the Follow TCP Stream menu item from the Wireshark Tools menu (or
use the context menu in the packet list). Wireshark will set an appropriate display filter and pop up
a dialog box with all the data from the TCP stream laid out in order, as shown in The “Follow TCP
Stream” dialog box.
Following a protocol stream applies a display filter which selects all the packets in the
TIP

current stream. Some people open the “Follow TCP Stream” dialog and immediately
close it as a quick way to isolate a particular stream. Closing the dialog with the “Back”
button will reset the display filter if this behavior is not desired.

Figure 68. The “Follow TCP Stream” dialog box

The stream content is displayed in the same sequence as it appeared on the network. Traffic from A
to B is marked in red, while traffic from B to A is marked in blue. If you like, you can change these
colors in the “Font and Colors” page in the “Preferences” dialog.

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Non-printable characters will be replaced by dots.
The stream content won’t be updated while doing a live capture. To get the latest content you’ll
have to reopen the dialog.
You can choose from the following actions:
[ Help ]
Show this help.
[ Filter out this stream ]
Apply a display filter removing the current stream data from the display.
[ Print ]
Print the stream data in the currently selected format.
[ Save as… ]
Save the stream data in the currently selected format.
[ Back ]
Close this dialog box and restore the previous display filter.
[ Close ]
Close this dialog box, leaving the current display filter in effect.
By default data from both directions is displayed. You can select the Entire conversation to switch
between both, client to server, or server to client data.
You can choose to view the data in one of the following formats:
ASCII
In this view you see the data from each direction in ASCII. Obviously best for ASCII based
protocols, e.g. HTTP.
C Arrays
This allows you to import the stream data into your own C program.
EBCDIC
For the big-iron freaks out there.
HEX Dump
This allows you to see all the data. This will require a lot of screen space and is best used with
binary protocols.
UTF-8
Like ASCII, but decode the data as UTF-8.

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UTF-16
Like ASCII, but decode the data as UTF-16.
YAML
This allows you to load the stream as YAML.
Raw
This allows you to load the unaltered stream data into a different program for further
examination. The display will look the same as the ASCII setting, but “Save As” will result in a
binary file.
You can switch between streams using the “Stream” selector.
You can search for text by entering it in the “Find” entry box and pressing [ Find Next ].

Show Packet Bytes
If a selected packet field does not show all the bytes (i.e. they are truncated when displayed) or if
they are shown as bytes rather than string or if they require more formatting because they contain
an image or HTML then this dialog can be used.
This dialog can also be used to decode field bytes from base64, zlib compressed or quoted-printable
and show the decoded bytes as configurable output. It’s also possible to select a subset of bytes
setting the start byte and end byte.
You can choose from the following actions:
[ Help ]
Show this help.
[ Print ]
Print the bytes in the currently selected format.
[ Copy ]
Copy the bytes to the clipboard in the currently selected format.
[ Save As ]
Save the bytes in the currently selected format.
[ Close ]
Close this dialog box.
You can choose to decode the data from one of the following formats:
None
This is the default which does not decode anything.
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Base64
This will decode from Base64.
Compressed
This will decompress the buffer using zlib.
Quoted-Printable
This will decode from a Quoted-Printable string.
ROT-13
This will decode ROT-13 encoded text.
You can choose to view the data in one of the following formats:
ASCII
In this view you see the bytes as ASCII. All control characters and non-ASCII bytes are replaced
by dot.
ASCII & Control
In this view all control characters are shown using a UTF-8 symbol and all non-ASCII bytes are
replaced by dot.
C Array
This allows you to import the field data into your own C program.
EBCDIC
For the big-iron freaks out there.
Hex Dump
This allows you to see all the data. This will require a lot of screen space and is best used with
binary protocols.
HTML
This allows you to see all the data formatted as a HTML document. The HTML supported is
what’s supported by the Qt QTextEdit class.
Image
This will try to convert the bytes into an image. Most popular formats are supported including
PNG, JPEG, GIF, and BMP.
ISO 8859-1
In this view you see the bytes as ISO 8859-1.
Raw
This allows you to load the unaltered stream data into a different program for further

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examination. The display will show HEX data, but “Save As” will result in a binary file.
UTF-8
In this view you see the bytes as UTF-8.
UTF-16
In this view you see the bytes as UTF-16.
YAML
This will show the bytes as a YAML binary dump.
You can search for text by entering it in the “Find” entry box and pressing [ Find Next ].

Expert Information
The expert infos is a kind of log of the anomalies found by Wireshark in a capture file.
The general idea behind the following “Expert Info” is to have a better display of “uncommon” or
just notable network behaviour. This way, both novice and expert users will hopefully find
probable network problems a lot faster, compared to scanning the packet list “manually” .
Expert infos are only a hint

WARNING

Take expert infos as a hint what’s worth looking at, but not more. For example,
the absence of expert infos doesn’t necessarily mean everything is OK.

The amount of expert infos largely depends on the protocol being used. While some common
protocols like TCP/IP will show detailed expert infos, most other protocols currently won’t show any
expert infos at all.
The following will first describe the components of a single expert info, then the User Interface.

Expert Info Entries
Each expert info will contain the following things which will be described in detail below.
Table 23. Some example expert infos

Packet #

Severity

Group

Protocol

Summary

Note

Sequence

TCP

Duplicate ACK (#1)

Chat

Sequence

TCP

Connection reset
(RST)

Note

Sequence

TCP

Keep-Alive

Warn

Sequence

TCP

Fast
retransmission
(suspected)

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Severity
Every expert info has a specific severity level. The following severity levels are used, in parentheses
are the colors in which the items will be marked in the GUI:
• Chat (grey): information about usual workflow, e.g. a TCP packet with the SYN flag set
• Note (cyan): notable things, e.g. an application returned an “usual” error code like HTTP 404
• Warn (yellow): warning, e.g. application returned an “unusual” error code like a connection
problem
• Error (red): serious problem, e.g. [Malformed Packet]
Group
There are some common groups of expert infos. The following are currently implemented:
• Checksum: a checksum was invalid
• Sequence: protocol sequence suspicious, e.g. sequence wasn’t continuous or a retransmission
was detected or …
• Response Code: problem with application response code, e.g. HTTP 404 page not found
• Request Code: an application request (e.g. File Handle == x), usually Chat level
• Undecoded: dissector incomplete or data can’t be decoded for other reasons
• Reassemble: problems while reassembling, e.g. not all fragments were available or an exception
happened while reassembling
• Protocol: violation of protocol specs (e.g. invalid field values or illegal lengths), dissection of this
packet is probably continued
• Malformed: malformed packet or dissector has a bug, dissection of this packet aborted
• Debug: debugging (should not occur in release versions)
It’s possible that more groups will be added in the future.
Protocol
The protocol in which the expert info was caused.
Summary
Each expert info will also have a short additional text with some further explanation.

“Expert Info” dialog
You can open the expert info dialog by selecting Analyze › Expert Info.

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Figure 69. The “Expert Info” dialog box

Errors / Warnings / Notes / Chats tabs
An easy and quick way to find the most interesting infos (rather than using the Details tab), is to
have a look at the separate tabs for each severity level. As the tab label also contains the number of
existing entries, it’s easy to find the tab with the most important entries.
There are usually a lot of identical expert infos only differing in the packet number. These identical
infos will be combined into a single line - with a count column showing how often they appeared in
the capture file. Clicking on the plus sign shows the individual packet numbers in a tree view.
Details tab
The Details tab provides the expert infos in a “log like” view, each entry on its own line (much like
the packet list). As the amount of expert infos for a capture file can easily become very large,
getting an idea of the interesting infos with this view can take quite a while. The advantage of this
tab is to have all entries in the sequence as they appeared, this is sometimes a help to pinpoint
problems.

“Colorized” Protocol Details Tree

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Figure 70. The “Colorized” protocol details tree

The protocol field causing an expert info is colorized, e.g. uses a cyan background for a note
severity level. This color is propagated to the toplevel protocol item in the tree, so it’s easy to find
the field that caused the expert info.
For the example screenshot above, the IP “Time to live” value is very low (only 1), so the
corresponding protocol field is marked with a cyan background. To easier find that item in the
packet tree, the IP protocol toplevel item is marked cyan as well.

“Expert” Packet List Column (optional)

Figure 71. The “Expert” packet list column

An optional “Expert Info Severity” packet list column is available that displays the most significant
severity of a packet or stays empty if everything seems OK. This column is not displayed by default
but can be easily added using the Preferences Columns page described in Preferences.

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TCP Analysis
By default, Wireshark’s TCP dissector tracks the state of each TCP session and provides additional
information when problems or potential problems are detected. Analysis is done once for each TCP
packet when a capture file is first opened. Packets are processed in the order in which they appear
in the packet list. You can enable or disable this feature via the “Analyze TCP sequence numbers”
TCP dissector preference.
For analysis of data or protocols layered on top of TCP (such as HTTP), see TCP Reassembly.

Figure 72. “TCP Analysis” packet detail items

TCP Analysis flags are added to the TCP protocol tree under “SEQ/ACK analysis”. Each flag is
described below. Terms such as “next expected sequence number” and “next expected
acknowledgement number” refer to the following”:
Next expected sequence number
The last-seen sequence number plus segment length. Set when there are no analysis flags and
and for zero window probes. This is initially zero and calculated based on the previous packet in
the same TCP flow. Note that this may not be the same as the tcp.nxtseq protocol field.
Next expected acknowledgement number
The last-seen sequence number for segments. Set when there are no analysis flags and for zero
window probes.
Last-seen acknowledgment number
Always set. Note that this is not the same as the next expected acknowledgment number.
Last-seen acknowledgment number
Always updated for each packet. Note that this is not the same as the next expected
acknowledgment number.

TCP ACKed unseen segment
Set when the expected next acknowledgement number is set for the reverse direction and it’s less

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than the current acknowledgement number.

TCP Dup ACK #
Set when all of the following are true:
• The segment size is zero.
• The window size is non-zero and hasn’t changed.
• The next expected sequence number and last-seen acknowledgment number are non-zero (i.e.
the connection has been established).
• SYN, FIN, and RST are not set.

TCP Fast Retransmission
Set when all of the following are true:
• This is not a keepalive packet.
• In the forward direction, the segment size is greater than zero or the SYN or FIN is set.
• The next expected sequence number is greater than the current sequence number.
• We have more than two duplicate ACKs in the reverse direction.
• The current sequence number equals the next expected acknowledgement number.
• We saw the last acknowledgement less than 20ms ago.
Supersedes “Out-Of-Order”, “Spurious Retransmission”, and “Retransmission”.

TCP Keep-Alive
Set when the segment size is zero or one, the current sequence number is one byte less than the
next expected sequence number, and any of SYN, FIN, or RST are set.
Supersedes

“Fast

Retransmission”,

“Out-Of-Order”,

“Spurious

Retransmission”,

and

“Retransmission”.

TCP Keep-Alive ACK
Set when all of the following are true:
• The segment size is zero.
• The window size is non-zero and hasn’t changed.
• The current sequence number is the same as the next expected sequence number.
• The current acknowledgement number is the same as the last-seen acknowledgement number.
• The most recently seen packet in the reverse direction was a keepalive.

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• The packet is not a SYN, FIN, or RST.
Supersedes “Dup ACK” and “ZeroWindowProbeAck”.

TCP Out-Of-Order
Set when all of the following are true:
• This is not a keepalive packet.
• In the forward direction, the segment length is greater than zero or the SYN or FIN is set.
• The next expected sequence number is greater than the current sequence number.
• The next expected sequence number and the next sequence number differ.
• The last segment arrived within the calculated RTT (3ms by default).
Supersedes “Spurious Retransmission” and “Retransmission”.

TCP Port numbers reused
Set when the SYN flag is set (not SYN+ACK), we have an existing conversation using the same
addresses and ports, and the sequencue number is different than the existing conversation’s initial
sequence number.

TCP Previous segment not captured
Set when the current sequence number is greater than the next expected sequence number.

TCP Spurious Retransmission
Checks for a retransmission based on analysis data in the reverse direction. Set when all of the
following are true:
• The SYN or FIN flag is set.
• This is not a keepalive packet.
• The segment length is greater than zero.
• Data for this flow has been acknowledged. That is, the last-seen acknowledgement number has
been set.
• The next sequence number is less than or equal to the last-seen acknowledgement number.
Supersedes “Retransmission”.

TCP Retransmission
Set when all of the following are true:

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• This is not a keepalive packet.
• In the forward direction, the segment length is greater than zero or the SYN or FIN flag is set.
• The next expected sequence number is greater than the current sequence number.

TCP Window Full
Set when the segment size is non-zero, we know the window size in the reverse direction, and our
segment size exceeds the window size in the reverse direction.

TCP Window Update
Set when the all of the following are true:
• The segment size is zero.
• The window size is non-zero and not equal to the last-seen window size.
• The sequence number is equal to the next expected sequence number.
• The acknowledgement number is equal to the last-seen acknowledgement number.
• None of SYN, FIN, or RST are set.

TCP ZeroWindow
Set when the window size is zero and non of SYN, FIN, or RST are set.

TCP ZeroWindowProbe
Set when the sequence number is equal to the next expected sequence number, the segment size is
one, and last-seen window size in the reverse direction was zero.

TCP ZeroWindowProbeAck
Set when the all of the following are true:
• The segment size is zero.
• The window size is zero.
• The sequence number is equal to the next expected sequence number.
• The acknowledgement number is equal to the last-seen acknowledgement number.
• The last-seen packet in the reverse direction was a zero window probe.
Supersedes “TCP Dup ACK”.

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Time Stamps
Time stamps, their precisions and all that can be quite confusing. This section will provide you with
information about what’s going on while Wireshark processes time stamps.
While packets are captured, each packet is time stamped as it comes in. These time stamps will be
saved to the capture file, so they also will be available for (later) analysis.
So where do these time stamps come from? While capturing, Wireshark gets the time stamps from
the libpcap (WinPcap) library, which in turn gets them from the operating system kernel. If the
capture data is loaded from a capture file, Wireshark obviously gets the data from that file.

Wireshark internals
The internal format that Wireshark uses to keep a packet time stamp consists of the date (in days
since 1.1.1970) and the time of day (in nanoseconds since midnight). You can adjust the way
Wireshark displays the time stamp data in the packet list, see the “Time Display Format” item in the
The “View” Menu for details.
While reading or writing capture files, Wireshark converts the time stamp data between the
capture file format and the internal format as required.
While capturing, Wireshark uses the libpcap (WinPcap) capture library which supports
microsecond resolution. Unless you are working with specialized capturing hardware, this
resolution should be adequate.

Capture file formats
Every capture file format that Wireshark knows supports time stamps. The time stamp precision
supported by a specific capture file format differs widely and varies from one second “0” to one
nanosecond “0.123456789”. Most file formats store the time stamps with a fixed precision (e.g.
microseconds), while some file formats are even capable of storing the time stamp precision itself
(whatever the benefit may be).
The common libpcap capture file format that is used by Wireshark (and a lot of other tools)
supports a fixed microsecond resolution “0.123456” only.
Writing data into a capture file format that doesn’t provide the capability to store the actual
precision will lead to loss of information. For example, if you load a capture file with nanosecond
resolution and store the capture data in a libpcap file (with microsecond resolution) Wireshark
obviously must reduce the precision from nanosecond to microsecond.

Accuracy
People often ask “Which time stamp accuracy is provided by Wireshark?”. Well, Wireshark doesn’t
create any time stamps itself but simply gets them from “somewhere else” and displays them. So

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accuracy will depend on the capture system (operating system, performance, etc) that you use.
Because of this, the above question is difficult to answer in a general way.
USB connected network adapters often provide a very bad time stamp accuracy. The
incoming packets have to take “a long and winding road” to travel through the USB
NOTE

cable until they actually reach the kernel. As the incoming packets are time stamped
when they are processed by the kernel, this time stamping mechanism becomes
very inaccurate.
Don’t use USB connected NICs when you need precise time stamp accuracy.

Time Zones
If you travel across the planet, time zones can be confusing. If you get a capture file from
somewhere around the world time zones can even be a lot more confusing ;-)
First of all, there are two reasons why you may not need to think about time zones at all:
• You are only interested in the time differences between the packet time stamps and don’t need
to know the exact date and time of the captured packets (which is often the case).
• You don’t get capture files from different time zones than your own, so there are simply no time
zone problems. For example, everyone in your team is working in the same time zone as
yourself.

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What are time zones?
People expect that the time reflects the sunset. Dawn should be in the morning maybe around
06:00 and dusk in the evening maybe at 20:00. These times will obviously vary depending on
the season. It would be very confusing if everyone on earth would use the same global time
as this would correspond to the sunset only at a small part of the world.
For that reason, the earth is split into several different time zones, each zone with a local time
that corresponds to the local sunset.
The time zone’s base time is UTC (Coordinated Universal Time) or Zulu Time (military and
aviation). The older term GMT (Greenwich Mean Time) shouldn’t be used as it is slightly
incorrect (up to 0.9 seconds difference to UTC). The UTC base time equals to 0 (based at
Greenwich, England) and all time zones have an offset to UTC between -12 to +14 hours!
For example: If you live in Berlin you are in a time zone one hour earlier than UTC, so you are
in time zone “+1” (time difference in hours compared to UTC). If it’s 3 o’clock in Berlin it’s 2
o’clock in UTC “at the same moment”.
Be aware that at a few places on earth don’t use time zones with even hour offsets (e.g. New
Delhi uses UTC+05:30)!
Further

information

can

found

at:

https://en.wikipedia.org/wiki/Time_zone

and

https://en.wikipedia.org/wiki/Coordinated_Universal_Time.

What is daylight saving time (DST)?
Daylight Saving Time (DST), also known as Summer Time is intended to “save” some daylight
during the summer months. To do this, a lot of countries (but not all!) add a DST hour to the
already existing UTC offset. So you may need to take another hour (or in very rare cases even
two hours!) difference into your “time zone calculations”.
Unfortunately, the date at which DST actually takes effect is different throughout the world.
You may also note, that the northern and southern hemispheres have opposite DST’s (e.g.
while it’s summer in Europe it’s winter in Australia).
Keep in mind: UTC remains the same all year around, regardless of DST!
Further information can be found at https://en.wikipedia.org/wiki/Daylight_saving.
Further time zone and DST information can be found at http://wwp.greenwichmeantime.com/ and
http://www.timeanddate.com/worldclock/.

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Set your computer’s time correctly!
If you work with people around the world it’s very helpful to set your computer’s time and time
zone right.
You should set your computers time and time zone in the correct sequence:
1. Set your time zone to your current location
2. Set your computer’s clock to the local time
This way you will tell your computer both the local time and also the time offset to UTC. Many
organizations simply set the time zone on their servers and networking gear to UTC in order to
make coordination and troubleshooting easier.
If you travel around the world, it’s an often made mistake to adjust the hours of your
TIP

computer clock to the local time. Don’t adjust the hours but your time zone setting
instead! For your computer, the time is essentially the same as before, you are simply
in a different time zone with a different local time.

You can use the Network Time Protocol (NTP) to automatically adjust your computer to the correct
time, by synchronizing it to Internet NTP clock servers. NTP clients are available for all operating
systems that Wireshark supports (and for a lot more), for examples see http://www.ntp.org/.

Wireshark and Time Zones
So what’s the relationship between Wireshark and time zones anyway?
Wireshark’s native capture file format (libpcap format), and some other capture file formats, such
as the Windows Sniffer, EtherPeek, AiroPeek, and Sun snoop formats, save the arrival time of
packets as UTC values. UN*X systems, and “Windows NT based” systems represent time internally
as UTC. When Wireshark is capturing, no conversion is necessary. However, if the system time zone
is not set correctly, the system’s UTC time might not be correctly set even if the system clock
appears to display correct local time. When capturing, WinPcap has to convert the time to UTC
before supplying it to Wireshark. If the system’s time zone is not set correctly, that conversion will
not be done correctly.
Other capture file formats, such as the Microsoft Network Monitor, DOS-based Sniffer, and Network
Instruments Observer formats, save the arrival time of packets as local time values.
Internally to Wireshark, time stamps are represented in UTC. This means that when reading
capture files that save the arrival time of packets as local time values, Wireshark must convert
those local time values to UTC values.
Wireshark in turn will display the time stamps always in local time. The displaying computer will
convert them from UTC to local time and displays this (local) time. For capture files saving the
arrival time of packets as UTC values, this means that the arrival time will be displayed as the local

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time in your time zone, which might not be the same as the arrival time in the time zone in which
the packet was captured. For capture files saving the arrival time of packets as local time values, the
conversion to UTC will be done using your time zone’s offset from UTC and DST rules, which means
the conversion will not be done correctly; the conversion back to local time for display might undo
this correctly, in which case the arrival time will be displayed as the arrival time in which the
packet was captured.
Table 24. Time zone examples for UTC arrival times (without DST)

Los Angeles New York

Madrid

London

Berlin

Tokyo

Capture File
(UTC)

10:00

Local Offset
to UTC

-8

-5

-1

Displayed
Time (Local
Time)

02:00

05:00

09:00

10:00

11:00

19:00

For example let’s assume that someone in Los Angeles captured a packet with Wireshark at exactly
2 o’clock local time and sends you this capture file. The capture file’s time stamp will be
represented in UTC as 10 o’clock. You are located in Berlin and will see 11 o’clock on your
Wireshark display.
Now you have a phone call, video conference or Internet meeting with that one to talk about that
capture file. As you are both looking at the displayed time on your local computers, the one in Los
Angeles still sees 2 o’clock but you in Berlin will see 11 o’clock. The time displays are different as
both Wireshark displays will show the (different) local times at the same point in time.
Conclusion: You may not bother about the date/time of the time stamp you currently look at unless
you must make sure that the date/time is as expected. So, if you get a capture file from a different
time zone and/or DST, you’ll have to find out the time zone/DST difference between the two local
times and “mentally adjust” the time stamps accordingly. In any case, make sure that every
computer in question has the correct time and time zone setting.

Packet Reassembly
What is it?
Network protocols often need to transport large chunks of data which are complete in themselves,
e.g. when transferring a file. The underlying protocol might not be able to handle that chunk size
(e.g. limitation of the network packet size), or is stream-based like TCP, which doesn’t know data
chunks at all.
In that case the network protocol has to handle the chunk boundaries itself and (if required) spread
the data over multiple packets. It obviously also needs a mechanism to determine the chunk

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boundaries on the receiving side.
Wireshark calls this mechanism reassembly, although a specific protocol specification might use a
different term for this (e.g. desegmentation, defragmentation, etc).

How Wireshark handles it
For some of the network protocols Wireshark knows of, a mechanism is implemented to find,
decode and display these chunks of data. Wireshark will try to find the corresponding packets of
this chunk, and will show the combined data as additional pages in the “Packet Bytes” pane (for
information about this pane. See The “Packet Bytes” Pane).

Figure 73. The “Packet Bytes” pane with a reassembled tab

Reassembly might take place at several protocol layers, so it’s possible that multiple tabs in the
“Packet Bytes” pane appear.
NOTE

You will find the reassembled data in the last packet of the chunk.

For example, in a HTTP GET response, the requested data (e.g. an HTML page) is returned.
Wireshark will show the hex dump of the data in a new tab “Uncompressed entity body” in the
“Packet Bytes” pane.
Reassembly is enabled in the preferences by default but can be disabled in the preferences for the
protocol in question. Enabling or disabling reassembly settings for a protocol typically requires two
things:
1. The lower level protocol (e.g., TCP) must support reassembly. Often this reassembly can be
enabled or disabled via the protocol preferences.
2. The higher level protocol (e.g., HTTP) must use the reassembly mechanism to reassemble
fragmented protocol data. This too can often be enabled or disabled via the protocol
preferences.
The tooltip of the higher level protocol setting will notify you if and which lower level protocol
setting also has to be considered.

TCP Reassembly
Protocols such as HTTP or TLS are likely to span multiple TCP segments. The TCP protocol
preference “Allow subdissector to reassemble TCP streams” (enabled by default) makes it possible

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for Wireshark to collect a contiguous sequence of TCP segments and hand them over to the higher
level protocol (for example, to reconstruct a full HTTP message). All but the final segment will be
marked with “[TCP segment of a reassembled PDU]” in the packet list.
Disable this preference to reduce memory and processing overhead if you are only interested in
TCP sequence number analysis (TCP Analysis). Keep in mind, though, that higher level protocols
might be wrongly dissected. For example, HTTP messages could be shown as “Continuation” and
TLS records could be shown as “Ignored Unknown Record”. Such results can also be observed if you
start capturing while a TCP connection was already started or when TCP segments are lost or
delivered out-of-order.
To reassemble of out-of-order TCP segments, the TCP protocol preference “Reassemble out-of-order
segments” (currently disabled by default) must be enabled in addition to the previous preference. If
all packets are received in-order, this preference will not have any effect. Otherwise (if missing
segments are encountered while sequentially processing a packet capture), it is assumes that the
new and missing segments belong to the same PDU. Caveats:
• Lost packets are assumed to be received out-of-order or retransmitted later. Applications
usually retransmit segments until these are acknowledged, but if the packet capture drops
packets, then Wireshark will not be able to reconstruct the TCP stream. In such cases, you can
try to disable this preference and hopefully have a partial dissection instead of seeing just “[TCP
segment of a reassembled PDU]” for every TCP segment.
• When doing a capture in monitor mode (IEEE 802.11), packets are more likely to get lost due to
signal reception issues. In that case it is recommended to disable the option.
• If the new and missing segments are in fact part of different PDUs, then processing is currently
delayed until no more segments are missing, even if the begin of the missing segments
completed a PDU. For example, assume six segments forming two PDUs ABC and DEF. When
received as ABECDF, an application can start processing the first PDU after receiving ABEC.
Wireshark however requires the missing segment D to be received as well. This issue will be
addressed in the future.
• In the GUI and during a two-pass dissection (tshark -2), the previous scenario will display both
PDUs in the packet with last segment (F) rather than displaying it in the first packet that has the
final missing segment of a PDU. This issue will be addressed in the future.
• When enabled, fields such as the SMB “Time from request” (smb.time) might be smaller if the
request follows other out-of-order segments (this reflects application behavior). If the previous
scenario however occurs, then the time of the request is based on the frame where all missing
segments are received.
Regardless of the setting of these two reassembly-related preferences, you can always use the
“Follow TCP Stream” option (Following Protocol Streams) which displays segments in the expected
order.

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Name Resolution
Name resolution tries to convert some of the numerical address values into a human readable
format. There are two possible ways to do these conversions, depending on the resolution to be
done: calling system/network services (like the gethostname() function) and/or resolve from
Wireshark specific configuration files. For details about the configuration files Wireshark uses for
name resolution and alike, see Files and Folders.
The name resolution feature can be enabled individually for the protocol layers listed in the
following sections.

Name Resolution drawbacks
Name resolution can be invaluable while working with Wireshark and may even save you hours of
work. Unfortunately, it also has its drawbacks.
• Name resolution will often fail. The name to be resolved might simply be unknown by the name
servers asked, or the servers are just not available and the name is also not found in
Wireshark’s configuration files.
• The resolved names are not stored in the capture file or somewhere else. So the resolved names
might not be available if you open the capture file later or on a different machine. Each time
you open a capture file it may look “slightly different” simply because you can’t connect to the
name server (which you could connect to before).
• DNS may add additional packets to your capture file. You may see packets to/from your machine
in your capture file, which are caused by name resolution network services of the machine
Wireshark captures from.
• Resolved DNS names are cached by Wireshark. This is required for acceptable performance.
However, if the name resolution information should change while Wireshark is running,
Wireshark won’t notice a change in the name resolution information once it gets cached. If this
information changes while Wireshark is running, e.g. a new DHCP lease takes effect, Wireshark
won’t notice it.
Name resolution in the packet list is done while the list is filled. If a name can be resolved after a
packet is added to the list, its former entry won’t be changed. As the name resolution results are
cached, you can use View › Reload to rebuild the packet list with the correctly resolved names.
However, this isn’t possible while a capture is in progress.

Ethernet name resolution (MAC layer)
Try to resolve an Ethernet MAC address (e.g. 00:09:5b:01:02:03) to something more “human
readable”.
ARP name resolution (system service): Wireshark will ask the operating system to convert an
Ethernet address to the corresponding IP address (e.g. 00:09:5b:01:02:03 → 192.168.0.1).

150

Ethernet codes (ethers file): If the ARP name resolution failed, Wireshark tries to convert the
Ethernet address to a known device name, which has been assigned by the user using an ethers file
(e.g. 00:09:5b:01:02:03 → homerouter).
Ethernet manufacturer codes (manuf file): If neither ARP or ethers returns a result, Wireshark tries
to convert the first 3 bytes of an ethernet address to an abbreviated manufacturer name, which has
been assigned by the IEEE (e.g. 00:09:5b:01:02:03 → Netgear_01:02:03).

IP name resolution (network layer)
Try to resolve an IP address (e.g. 216.239.37.99) to something more “human readable”.
DNS name resolution (system/library service): Wireshark will use a name resolver to convert an IP
address to the hostname associated with it (e.g. 216.239.37.99 → www.1.google.com).
DNS name resolution can generally be performed synchronously or asynchronously. Both
mechanisms can be used to convert an IP address to some human readable (domain) name. A
system call like gethostname() will try to convert the address to a name. To do this, it will first ask
the systems hosts file (e.g. /etc/hosts) if it finds a matching entry. If that fails, it will ask the
configured DNS server(s) about the name.
So the real difference between synchronous DNS and asynchronous DNS comes when the system
has to wait for the DNS server about a name resolution. The system call gethostname() will wait
until a name is resolved or an error occurs. If the DNS server is unavailable, this might take quite a
while (several seconds).
To provide acceptable performance Wireshark depends on an asynchronous
WARNING

DNS library to do name resolution. If one isn’t available during compilation
the feature will be unavailable.

The asynchronous DNS service works a bit differently. It will also ask the DNS server, but it won’t
wait for the answer. It will just return to Wireshark in a very short amount of time. The actual (and
the following) address fields won’t show the resolved name until the DNS server returns an answer.
As mentioned above, the values get cached, so you can use View › Reload to “update” these fields to
show the resolved values.
hosts name resolution (hosts file): If DNS name resolution failed, Wireshark will try to convert an IP
address to the hostname associated with it, using a hosts file provided by the user (e.g. 216.239.37.99
→ www.google.com).

TCP/UDP port name resolution (transport layer)
Try to resolve a TCP/UDP port (e.g. 80) to something more “human readable”.
TCP/UDP port conversion (system service): Wireshark will ask the operating system to convert a TCP
or UDP port to its well known name (e.g. 80 → http).

151

VLAN ID resolution
To get a descriptive name for a VLAN tag ID a vlans file can be used.

SS7 point code resolution
To get a node name for a SS7 point code a ss7pcs file can be used.

Checksums
Several network protocols use checksums to ensure data integrity. Applying checksums as
described here is also known as redundancy checking.

152

What are checksums for?
Checksums are used to ensure the integrity of data portions for data transmission or storage.
A checksum is basically a calculated summary of such a data portion.
Network data transmissions often produce errors, such as toggled, missing or duplicated bits.
As a result, the data received might not be identical to the data transmitted, which is
obviously a bad thing.
Because of these transmission errors, network protocols very often use checksums to detect
such errors. The transmitter will calculate a checksum of the data and transmits the data
together with the checksum. The receiver will calculate the checksum of the received data
with the same algorithm as the transmitter. If the received and calculated checksums don’t
match a transmission error has occurred.
Some checksum algorithms are able to recover (simple) errors by calculating where the
expected error must be and repairing it.
If there are errors that cannot be recovered, the receiving side throws away the packet.
Depending on the network protocol, this data loss is simply ignored or the sending side needs
to detect this loss somehow and retransmits the required packet(s).
Using a checksum drastically reduces the number of undetected transmission errors.
However, the usual checksum algorithms cannot guarantee an error detection of 100%, so a
very small number of transmission errors may remain undetected.
There are several different kinds of checksum algorithms; an example of an often used
checksum algorithm is CRC32. The checksum algorithm actually chosen for a specific network
protocol will depend on the expected error rate of the network medium, the importance of
error detection, the processor load to perform the calculation, the performance needed and
many other things.
Further information about checksums can be found at: https://en.wikipedia.org/wiki/
Checksum.

Wireshark checksum validation
Wireshark will validate the checksums of many protocols, e.g. IP, TCP, UDP, etc.
It will do the same calculation as a “normal receiver” would do, and shows the checksum fields in
the packet details with a comment, e.g. [correct] or [invalid, must be 0x12345678].
Checksum validation can be switched off for various protocols in the Wireshark protocol
preferences, e.g. to (very slightly) increase performance.
If the checksum validation is enabled and it detected an invalid checksum, features like packet

153

reassembly won’t be processed. This is avoided as incorrect connection data could “confuse” the
internal database.

Checksum offloading
The checksum calculation might be done by the network driver, protocol driver or even in
hardware.
For example: The Ethernet transmitting hardware calculates the Ethernet CRC32 checksum and the
receiving hardware validates this checksum. If the received checksum is wrong Wireshark won’t
even see the packet, as the Ethernet hardware internally throws away the packet.
Higher level checksums are “traditionally” calculated by the protocol implementation and the
completed packet is then handed over to the hardware.
Recent network hardware can perform advanced features such as IP checksum calculation, also
known as checksum offloading. The network driver won’t calculate the checksum itself but will
simply hand over an empty (zero or garbage filled) checksum field to the hardware.
Checksum offloading often causes confusion as the network packets to be
transmitted are handed over to Wireshark before the checksums are actually
NOTE

calculated. Wireshark gets these “empty” checksums and displays them as invalid,
even though the packets will contain valid checksums when they leave the network
hardware later.

Checksum offloading can be confusing and having a lot of [invalid] messages on the screen can be
quite annoying. As mentioned above, invalid checksums may lead to unreassembled packets,
making the analysis of the packet data much harder.
You can do two things to avoid this checksum offloading problem:
• Turn off the checksum offloading in the network driver, if this option is available.
• Turn off checksum validation of the specific protocol in the Wireshark preferences. Recent
releases of Wireshark disable checksum validation by default due to the prevalance of
offloading in modern hardware and operating systems.

154

Statistics
Introduction
Wireshark provides a wide range of network statistics which can be accessed via the Statistics
menu.
These statistics range from general information about the loaded capture file (like the number of
captured packets), to statistics about specific protocols (e.g. statistics about the number of HTTP
requests and responses captured).
• General statistics:
◦ Capture File Properties about the capture file.
◦ Protocol Hierarchy of the captured packets.
◦ Conversations e.g. traffic between specific IP addresses.
◦ Endpoints e.g. traffic to and from an IP addresses.
◦ IO Graphs visualizing the number of packets (or similar) in time.
• Protocol specific statistics:
◦ Service Response Time between request and response of some protocols.
◦ Various other protocol specific statistics.
The protocol specific statistics require detailed knowledge about the specific
NOTE

protocol. Unless you are familiar with that protocol, statistics about it will be pretty
hard to understand.

Wireshark has many other statistics windows that display detailed information about specific
protocols and might be described in a later version of this document.
Some of these statistics are described at https://wiki.wireshark.org/Statistics.

The “Capture File Properties” Window
General statistics about the current capture file.

155

Figure 74. The “Capture File Properties” window

• File: general information about the capture file.
• Time: the timestamps when the first and the last packet were captured (and the time between
them).
• Capture: information from the time when the capture was done (only available if the packet
data was captured from the network and not loaded from a file).

156

• Interface: information about the capture interface.
• Statistics: some statistics of the network traffic seen. If a display filter is set, you will see values
in the Captured column, and if any packages are marked, you will see values in the Marked
column. The values in the Captured column will remain the same as before, while the values in
the Displayed column will reflect the values corresponding to the packets shown in the display.
The values in the Marked column will reflect the values corresponding to the marked packages.

Resolved Addresses
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

The “Protocol Hierarchy” Window
The protocol hierarchy of the captured packets.

Figure 75. The “Protocol Hierarchy” Window

This is a tree of all the protocols in the capture. Each row contains the statistical values of one
protocol. Two of the columns (Percent Packets and Percent Bytes) serve double duty as bar graphs. If
a display filter is set it will be shown at the bottom.
The [ Copy ] button will let you copy the window contents as CSV or YAML.
Protocol hierarchy columns

Protocol
This protocol’s name
Percent Packets
The percentage of protocol packets relative to all packets in the capture
Packets

157

The total number of packets of this protocol
Percent Bytes
The percentage of protocol bytes relative to the total bytes in the capture
Bytes
The total number of bytes of this protocol
Bits/s
The bandwidth of this protocol relative to the capture time
End Packets
The absolute number of packets of this protocol where it was the highest protocol in the stack
(last dissected)
End Bytes
The absolute number of bytes of this protocol where it was the highest protocol in the stack (last
dissected)
End Bits/s
The bandwidth of this protocol relative to the capture time where was the highest protocol in
the stack (last dissected)
Packets usually contain multiple protocols. As a result more than one protocol will be counted for
each packet. Example: In the screenshot IP has 99.9% and TCP 98.5% (which is together much more
than 100%).
Protocol layers can consist of packets that won’t contain any higher layer protocol, so the sum of all
higher layer packets may not sum up to the protocols packet count. Example: In the screenshot TCP
has 98.5% but the sum of the subprotocols (SSL, HTTP, etc) is much less. This can be caused by
continuation frames, TCP protocol overhead, and other undissected data.
A single packet can contain the same protocol more than once. In this case, the protocol is counted
more than once. For example ICMP replies and many tunneling protocols will carry more than one
IP header.

Conversations
A network conversation is the traffic between two specific endpoints. For example, an IP
conversation is all the traffic between two IP addresses. The description of the known endpoint
types can be found in Endpoints.

The “Conversations” Window
The conversations window is similar to the endpoint Window. See The “Endpoints” Window for a

158

description of their common features. Along with addresses, packet counters, and byte counters the
conversation window adds four columns: the start time of the conversation (“Rel Start”) or (“Abs
Start”), the duration of the conversation in seconds, and the average bits (not bytes) per second in
each direction. A timeline graph is also drawn across the “Rel Start” / “Abs Start” and “Duration”
columns.

Figure 76. The “Conversations” window

Each row in the list shows the statistical values for exactly one conversation.
Name resolution will be done if selected in the window and if it is active for the specific protocol
layer (MAC layer for the selected Ethernet endpoints page). Limit to display filter will only show
conversations matching the current display filter. Absolute start time switches the start time
column between relative (“Rel Start”) and absolute (“Abs Start”) times. Relative start times match
the “Seconds Since Beginning of Capture” time display format in the packet list and absolute start
times match the “Time of Day” display format.
The [ Copy ] button will copy the list values to the clipboard in CSV (Comma Separated Values) or
YAML format. The [ Follow Stream… ] button will show the stream contents as described in The
“Follow TCP Stream” dialog box dialog. The [ Graph… ] button will show a graph as described in
The “I/O Graph” Window.
[ Conversation Types ] lets you choose which traffic type tabs are shown. See Endpoints for a list of
endpoint types. The enabled types are saved in your profile settings.
TIP

This window will be updated frequently so it will be useful even if you open it before
(or while) you are doing a live capture.

Endpoints
A network endpoint is the logical endpoint of separate protocol traffic of a specific protocol layer.
The endpoint statistics of Wireshark will take the following endpoints into account:

159

TIP

If you are looking for a feature other network tools call a hostlist, here is the right
place to look. The list of Ethernet or IP endpoints is usually what you’re looking for.

Endpoint and Conversation types

Bluetooth
A MAC-48 address similar to Ethernet.
Ethernet
Identical to the Ethernet device’s MAC-48 identifier.
Fibre Channel
A MAC-48 address similar to Ethernet.
IEEE 802.11
A MAC-48 address similar to Ethernet.
FDDI
Identical to the FDDI MAC-48 address.
IPv4
Identical to the 32-bit IPv4 address.
IPv6
Identical to the 128-bit IPv6 address.
IPX
A concatenation of a 32 bit network number and 48 bit node address, by default the Ethernet
interface’s MAC-48 address.
JXTA
A 160 bit SHA-1 URN.
NCP
Similar to IPX.
RSVP
A combination of varios RSVP session attributes and IPv4 addresses.
SCTP
A combination of the host IP addresses (plural) and the SCTP port used. So different SCTP ports
on the same IP address are different SCTP endpoints, but the same SCTP port on different IP
addresses of the same host are still the same endpoint.
TCP

160

A combination of the IP address and the TCP port used. Different TCP ports on the same IP
address are different TCP endpoints.
Token Ring
Identical to the Token Ring MAC-48 address.
UDP
A combination of the IP address and the UDP port used, so different UDP ports on the same IP
address are different UDP endpoints.
USB
Identical to the 7-bit USB address.
Broadcast and multicast endpoints

NOTE

Broadcast and multicast traffic will be shown separately as additional endpoints. Of
course, as these aren’t physical endpoints the real traffic will be received by some
or all of the listed unicast endpoints.

The “Endpoints” Window
This window shows statistics about the endpoints captured.

Figure 77. The “Endpoints” window

For each supported protocol, a tab is shown in this window. Each tab label shows the number of
endpoints captured (e.g. the tab label “Ethernet · 4” tells you that four ethernet endpoints have been
captured). If no endpoints of a specific protocol were captured, the tab label will be greyed out
(although the related page can still be selected).
Each row in the list shows the statistical values for exactly one endpoint.
Name resolution will be done if selected in the window and if it is active for the specific protocol
layer (MAC layer for the selected Ethernet endpoints page). Limit to display filter will only show

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conversations matching the current display filter. Note that in this example we have MaxMind DB
configured which gives us extra geographic columns. See MaxMind Database Paths for more
information.
The [ Copy ] button will copy the list values to the clipboard in CSV (Comma Separated Values) or
YAML format.
[ Endpoint Types ] lets you choose which traffic type tabs are shown. See Endpoints above for a list
of endpoint types. The enabled types are saved in your profile settings.
TIP

This window will be updated frequently, so it will be useful even if you open it before
(or while) you are doing a live capture.

Packet Lengths
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

The “I/O Graph” Window
User configurable graph of the captured network packets.
You can define up to five differently colored graphs.

Figure 78. The “IO Graphs” window

The user can configure the following things:

162

• Graphs
◦ Graph 1-5: enable the specific graph 1-5 (only graph 1 is enabled by default)
◦ Color: the color of the graph (cannot be changed)
◦ Filter: a display filter for this graph (only the packets that pass this filter will be taken into
account for this graph)
◦ Style: the style of the graph (Line/Impulse/FBar/Dot)
• X Axis
◦ Tick interval: an interval in x direction lasts (10/1 minutes or 10/1/0.1/0.01/0.001 seconds)
◦ Pixels per tick: use 10/5/2/1 pixels per tick interval
◦ View as time of day: option to view x direction labels as time of day instead of seconds or
minutes since beginning of capture
• Y Axis
◦ Unit: the unit for the y direction (Packets/Tick, Bytes/Tick, Bits/Tick, Advanced…) [XXX describe the Advanced feature.]
◦ Scale: the scale for the y unit (Logarithmic,Auto,10,20,50,100,200,500,…)
The [ Save ] button will save the currently displayed portion of the graph as one of various file
formats.
The [ Copy ] button will copy values from selected graphs to the clipboard in CSV (Comma
Separated Values) format.
TIP

Click in the graph to select the first package in the selected interval.

Service Response Time
The service response time is the time between a request and the corresponding response. This
information is available for many protocols.
Service response time statistics are currently available for the following protocols:
• DCE-RPC
• Fibre Channel
• H.225 RAS
• LDAP
• LTE MAC
• MGCP
• ONC-RPC

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• SMB
As an example, the DCE-RPC service response time is described in more detail.
NOTE

The other Service Response Time windows will work the same way (or only slightly
different) compared to the following description.

The “Service Response Time DCE-RPC” Window
The service response time of DCE-RPC is the time between the request and the corresponding
response.
First of all, you have to select the DCE-RPC interface:

Figure 79. The “Compute DCE-RPC statistics” window

You can optionally set a display filter, to reduce the amount of packets.

164

Figure 80. The “DCE-RPC Statistic for …” window

Each row corresponds to a method of the interface selected (so the EPM interface in version 3 has 7
methods). For each method the number of calls, and the statistics of the SRT time is calculated.

DHCP (BOOTP) Statistics
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

ONC-RPC Programs
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

29West
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

ANCP
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

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BACnet
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

Collectd
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

DNS
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

Flow Graph
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

HART-IP
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

HPFEEDS
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

HTTP Statistics
HTTP Packet Counter
Statistics for HTTP request types and response codes.

HTTP Requests
HTTP statistics based on the host and URI.

HTTP Load Distribution
HTTP request and response statistics based on the server address and host.

HTTP Request Sequences
HTTP Request Sequences uses HTTP’s Referer and Location headers to sequence a capture’s HTTP
requests as a tree. This enables analysts to see how one HTTP request leads to the next.

166

Figure 81. The “HTTP Request Sequences” window

HTTP2
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

Sametime
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

TCP Stream Graphs
Show different visual representations of the TCP streams in a capture.
Time Sequence (Stevens)
This is a simple graph of the TCP sequence number over time, similar to the ones used in
Richard Stevens’ “TCP/IP Illustrated” series of books.
Time Sequence (tcptrace)
Shows

TCP

metrics

similar

the

tcptrace

utility,

including

forward

segments,

acknowledgements, selective acknowledgements, reverse window sizes, and zero windows.
Throughput
Average throughput and goodput.

167

Round Trip Time
Round trip time vs time or sequence number. RTT is based on the acknowledgement timestamp
corresponding to a particular segment.
Window Scaling
Window size and outstanding bytes.

UDP Multicast Graphs
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

F5
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

IPv4 Statistics
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

IPv6 Statistics
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

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Telephony
Introduction
Wireshark provides a wide range of telephony related network statistics which can be accessed via
the Telephony menu.
These statistics range from specific signaling protocols, to analysis of signaling and media flows. If
encoded in a compatible encoding the media flow can even be played.
The protocol specific statistics windows display detailed information of specific protocols and might
be described in a later version of this document.
Some of these statistics are described at the https://wiki.wireshark.org/Statistics pages.

VoIP Calls
The VoIP Calls window shows a list of all detected VoIP calls in the captured traffic. It finds calls by
their signaling.
More details can be found on the https://wiki.wireshark.org/VoIP_calls page.

ANSI
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

GSM
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

IAX2 Stream Analysis
The “IAX2 Stream Analysis” dialog shows statistics for the forward and reverse streams of a
selected IAX2 call along with a graph.

ISUP Messages
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

LTE

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LTE MAC Traffic Statistics
Statistics of the captured LTE MAC traffic. This window will summarize the LTE MAC traffic found
in the capture.

Figure 82. The “LTE MAC Traffic Statistics” window

The top pane shows statistics for common channels. Each row in the middle pane shows statistical
highlights for exactly one UE/C-RNTI. In the lower pane, you can see the for the currently selected
UE/C-RNTI the traffic broken down by individual channel.

LTE RLC Graph
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

LTE RLC Traffic Statistics
Statistics of the captured LTE RLC traffic. This window will summarize the LTE RLC traffic found in
the capture.

170

Figure 83. The “LTE RLC Traffic Statistics” window

At the top, the check-box allows this window to include RLC PDUs found within MAC PDUs or not.
This will affect both the PDUs counted as well as the display filters generated (see below).
The upper list shows summaries of each active UE. Each row in the lower list shows statistical
highlights for individual channels within the selected UE.
The lower part of the windows allows display filters to be generated and set for the selected
channel. Note that in the case of Acknowledged Mode channels, if a single direction is chosen, the
generated filter will show data in that direction and control PDUs in the opposite direction.

MTP3
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

Osmux
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

RTP Analysis
The RTP analysis function takes the selected RTP stream (and the reverse stream, if possible) and
generates a list of statistics on it.

171

Figure 84. The “RTP Stream Analysis” window

Starting with basic data as packet number and sequence number, further statistics are created
based on arrival time, delay, jitter, packet size, etc.
Besides the per packet statistics, the lower pane shows the overall statistics, with minimums and
maximums for delta, jitter and clock skew. Also an indication of lost packets is included.
The RTP Stream Analysis window further provides the option to save the RTP payload (as raw data
or, if in a PCM encoding, in an Audio file). Other options a to export and plot various statistics on
the RTP streams.
The RTP Player window lets you play back RTP audio data. In order to use this feature your version
of Wireshark must support audio and the codecs used by each RTP stream.
More details can be found on the https://wiki.wireshark.org/VoIP_calls page.

RTSP
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

SCTP
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

SMPP Operations
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

172

UCP Messages
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

H.225
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

SIP Flows
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

SIP Statistics
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

WAP-WSP Packet Counter
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

173

Wireless
Introduction
The Wireless menu provides access to statistics related to wireless traffic.

Bluetooth ATT Server Attributes
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

Bluetooth Devices
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

Bluetooth HCI Summary
Not yet written. See https://wiki.wireshark.org/Development/SubmittingPatches

WLAN Traffic
Statistics about captured WLAN traffic. This can be found under the Wireless menu and
summarizes the wireless network traffic found in the capture. Probe requests will be merged into
an existing network if the SSID matches.

Figure 85. The “WLAN Traffic Statistics” window

Each row in the list shows the statistical values for exactly one wireless network.
Name resolution will be done if selected in the window and if it is active for the MAC layer.
Only show existing networks will exclude probe requests with a SSID not matching any network
from the list.

174

The [ Copy ] button will copy the list values to the clipboard in CSV (Comma Separated Values)
format.
TIP

This window will be updated frequently, so it will be useful, even if you open it before
(or while) you are doing a live capture.

175

Customizing Wireshark
Introduction
Wireshark’s default behaviour will usually suit your needs pretty well. However, as you become
more familiar with Wireshark, it can be customized in various ways to suit your needs even better.
In this chapter we explore:
• How to start Wireshark with command line parameters
• How to colorize the packet list
• How to control protocol dissection
• How to use the various preference settings

Start Wireshark from the command line
You can start Wireshark from the command line, but it can also be started from most Window
managers as well. In this section we will look at starting it from the command line.
Wireshark supports a large number of command line parameters. To see what they are, simply
enter the command wireshark -h and the help information shown in Help information available
from Wireshark (or something similar) should be printed.
Example 3. Help information available from Wireshark

Wireshark 2.1.0 (v2.1.0rc0-502-g328fbc0 from master)
Interactively dump and analyze network traffic.
See https://www.wireshark.org for more information.
Usage: wireshark [options] ... [ ]
Capture interface:
-i
-f

name or idx of interface (def: first non-loopback)
packet filter in libpcap filter syntax or
predef:filtername - predefined filtername from GUI
-s
packet snapshot length (def: 262144)
-p
don’t capture in promiscuous mode
-k
start capturing immediately (def: do nothing)
-S
update packet display when new packets are captured
-l
turn on automatic scrolling while -S is in use
-I
capture in monitor mode, if available
-B
size of kernel buffer (def: 2MB)
-y
link layer type (def: first appropriate)
--time-stamp-type timestamp method for interface

176

-D
-L
--list-time-stamp-types
Capture stop conditions:
-c
-a ...

print list of interfaces and exit
print list of link-layer types of iface and exit
print list of timestamp types for iface and exit

stop after n
duration:NUM
filesize:NUM
files:NUM

packets (def: infinite)
- stop after NUM seconds
- stop this file after NUM KB
- stop after NUM files

Capture output:
-b ... duration:NUM - switch to next file after NUM secs
filesize:NUM - switch to next file after NUM KB
files:NUM - ringbuffer: replace after NUM files
RPCAP options:
-A :
use RPCAP password authentication
Input file:
-r
set the filename to read from (no pipes or stdin!)
Processing:
-R
packet filter in Wireshark display filter syntax
-n
disable all name resolutions (def: all enabled)
-N enable specific name resolution(s): "mnNtCd"
-d ==, ...
"Decode As”, see the man page for details
Example: tcp.port==8888,http
--disable-protocol
disable dissection of proto_name
--enable-heuristic
enable dissection of heuristic protocol
--disable-heuristic
disable dissection of heuristic protocol
User
-C
-Y
-g
-J
-j
-m
-t
-u
-X
-z

interface:

a|ad|d|dd|e|r|u|ud
s|hms
:

Output:
-w

start with specified configuration profile
start with the given display filter
go to specified packet number after "-r"
jump to the first packet matching the (display)
filter
search backwards for a matching packet after "-J"
set the font name used for most text
output format of time stamps (def: r: rel. to first)
output format of seconds (def: s: seconds)
eXtension options, see man page for details
show various statistics, see man page for details

set the output filename (or '-' for stdout)

177

Miscellaneous:
-h
-v
-P :
-o : ...
-K

display this help and exit
display version info and exit
persconf:path - personal configuration files
persdata:path - personal data files
override preference or recent setting
keytab file to use for kerberos decryption

We will examine each of the command line options in turn.
The first thing to notice is that issuing the command wireshark by itself will bring up Wireshark.
However, you can include as many of the command line parameters as you like. Their meanings
are as follows ( in alphabetical order ):
-a
Specify a criterion that specifies when Wireshark is to stop writing to a capture file. The
criterion is of the form test:value, where test is one of:
duration:value
Stop writing to a capture file after value of seconds have elapsed.
filesize:value
Stop writing to a capture file after it reaches a size of value kilobytes (where a kilobyte is 1000
bytes, not 1024 bytes). If this option is used together with the -b option, Wireshark will stop
writing to the current capture file and switch to the next one if filesize is reached.
files:value
Stop writing to capture files after value number of files were written.
-b
If a maximum capture file size was specified, this option causes Wireshark to run in “ring
buffer” mode, with the specified number of files. In “ring buffer” mode, Wireshark will write to
several capture files. Their name is based on the number of the file and on the creation date and
time.
When the first capture file fills up Wireshark will switch to writing to the next file, and so on.
With the files option it’s also possible to form a “ring buffer.” This will
fill up new files until the number of files specified, at which point the data in the first file will be
discarded so a new file can be written.
If the optional duration is specified, Wireshark will also switch to the
next file when the specified number of seconds has elapsed even if the current file is not
completely fills up.
duration:value

178

Switch to the next file after value seconds have elapsed, even if the current file is not
completely filled up.
filesize:value
Switch to the next file after it reaches a size of value kilobytes (where a kilobyte is 1000 bytes,
not 1024 bytes).
files:value
Begin again with the first file after value number of files were written (form a ring buffer).
-B
Set capture buffer size (in MB, default is 1MB). This is used by the capture driver to buffer packet
data until that data can be written to disk. If you encounter packet drops while capturing, try to
increase this size. Not supported on some platforms.
-c
This option specifies the maximum number of packets to capture when capturing live data. It
would be used in conjunction with the -k option.
-D
Print a list of the interfaces on which Wireshark can capture, then exit. For each network
interface, a number and an interface name, possibly followed by a text description of the
interface, is printed. The interface name or the number can be supplied to the -i flag to specify
an interface on which to capture.
This can be useful on systems that don’t have a command to list them (e.g., Windows systems, or
UNIX systems lacking ifconfig -a). The number can be especially useful on Windows, where the
interface name is a GUID.
Note that “can capture” means that Wireshark was able to open that device to do a live capture.
If, on your system, a program doing a network capture must be run from an account with
special privileges (for example, as root), then, if Wireshark is run with the -D flag and is not run
from such an account, it will not list any interfaces.
-f
This option sets the initial capture filter expression to be used when capturing packets.
-g
After reading in a capture file using the -r flag, go to the given packet number.
-h
The -h option requests Wireshark to print its version and usage instructions (as shown above)
and exit.
-i

179

Set the name of the network interface or pipe to use for live packet capture.
Network interface names should match one of the names listed in wireshark -D (described
above). A number, as reported by wireshark -D, can also be used. If you’re using UNIX, netstat -i
or ifconfig -a might also work to list interface names, although not all versions of UNIX support
the -a flag to ifconfig.
If no interface is specified, Wireshark searches the list of interfaces, choosing the first nonloopback interface if there are any non-loopback interfaces, and choosing the first loopback
interface if there are no non-loopback interfaces; if there are no interfaces, Wireshark reports
an error and doesn’t start the capture.
Pipe names should be either the name of a FIFO (named pipe) or “-” to read data from the
standard input. Data read from pipes must be in standard libpcap format.
-J
After reading in a capture file using the -r flag, jump to the first packet which matches the filter
expression. The filter expression is in display filter format. If an exact match cannot be found
the first packet afterwards is selected.
-I
Capture wireless packets in monitor mode if available.
-j
Use this option after the -J option to search backwards for a first packet to go to.
-k
The -k option specifies that Wireshark should start capturing packets immediately. This option
requires the use of the -i parameter to specify the interface that packet capture will occur from.
-K
Use the specified file for Kerberos decryption.
-l
This option turns on automatic scrolling if the packet list pane is being updated automatically as
packets arrive during a capture ( as specified by the -S flag).
-L
List the data link types supported by the interface and exit.
--list-time-stamp-types
List timestamp types configurable for the iface and exit
-m
This option sets the name of the font used for most text displayed by Wireshark.

180

-n
Disable network object name resolution (such as hostname, TCP and UDP port names).
-N
Turns on name resolving for particular types of addresses and port numbers. The argument is a
string that may contain the letters m to enable MAC address resolution, n to enable network
address resolution, and t to enable transport-layer port number resolution. This overrides -n if
both -N and -n are present. The letter d enables resolution from captured DNS packets.
-o
Sets a preference or recent value, overriding the default value and any value read from a
preference or recent file. The argument to the flag is a string of the form prefname:value, where
prefname is the name of the preference (which is the same name that would appear in the
preferences or recent file), and value is the value to which it should be set. Multiple instances of
`-o ` can be given on a single command line.
An example of setting a single preference would be:

wireshark -o mgcp.display_dissect_tree:TRUE
An example of setting multiple preferences would be:

wireshark -o mgcp.display_dissect_tree:TRUE -o mgcp.udp.callagent_port:2627
You can get a list of all available preference strings from the preferences file. See Files and
Folders for details.
User access tables can be overridden using “uat,” followed by the UAT file name and a valid
record for the file:

wireshark -o "uat:user_dlts:\"User 0 (DLT=147)\",\"http\",\"0\",\"\",\"0\",\"\""
The example above would dissect packets with a libpcap data link type 147 as HTTP, just as if
you had configured it in the DLT_USER protocol preferences.
-p
Don’t put the interface into promiscuous mode. Note that the interface might be in promiscuous
mode for some other reason. Hence, -p cannot be used to ensure that the only traffic that is
captured is traffic sent to or from the machine on which Wireshark is running, broadcast traffic,
and multicast traffic to addresses received by that machine.
-P

181

Special path settings usually detected automatically. This is used for special cases, e.g. starting
Wireshark from a known location on an USB stick.
The criterion is of the form key:path, where key is one of:
persconf:path
Path of personal configuration files, like the preferences files.
persdata:path
Path of personal data files, it’s the folder initially opened. After the initialization, the recent
file will keep the folder last used.
-Q
This option forces Wireshark to exit when capturing is complete. It can be used with the -c
option. It must be used in conjunction with the -i and -w options.
-r
This option provides the name of a capture file for Wireshark to read and display. This capture
file can be in one of the formats Wireshark understands.
-R
This option specifies a display filter to be applied when reading packets from a capture file. The
syntax of this filter is that of the display filters discussed in Filtering packets while viewing.
Packets not matching the filter are discarded.
-s
This option specifies the snapshot length to use when capturing packets. Wireshark will only
capture snaplen bytes of data for each packet.
-S
This option specifies that Wireshark will display packets as it captures them. This is done by
capturing in one process and displaying them in a separate process. This is the same as “Update
list of packets in real time” in the “Capture Options” dialog box.
-t
This option sets the format of packet timestamps that are displayed in the packet list window.
The format can be one of:
r
Relative, which specifies timestamps are displayed relative to the first packet captured.
a
Absolute, which specifies that actual times be displayed for all packets.
ad

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Absolute with date, which specifies that actual dates and times be displayed for all packets.
d
Delta, which specifies that timestamps are relative to the previous packet.
e
Epoch, which specifies that timestamps are seconds since epoch (Jan 1, 1970 00:00:00)
-u
Show timesamps as seconds (“s”, the default) or hours, minutes, and seconds (“hms”)
-v
The -v option requests Wireshark to print out its version information and exit.
-w
This option sets the name of the file to be used to save captured packets.
-y
If a capture is started from the command line with -k, set the data link type to use while
capturing packets. The values reported by -L are the values that can be used.
--time-stamp-type
If a capture is started from the command line with -k, set the data link type to use while
capturing packets. The values reported by --list-time-stamp-types are the values that can be
used.
-X
Specify an option to be passed to a TShark module. The eXtension option is in the form
extension_key:value, where extension_key can be:
lua_script:lua_script_filename
Tells Wireshark to load the given script in addition to the default Lua scripts.
lua_script[num]:argument
Tells Wireshark to pass the given argument to the lua script identified by num, which is the
number indexed order of the lua_script command. For example, if only one script was loaded
with -X lua_script:my.lua, then -X lua_script1:foo will pass the string foo to the my.lua
script. If two scripts were loaded, such as -X lua_script:my.lua and -X lua_script:other.lua
in that order, then a -X lua_script2:bar would pass the string bar to the second lua script,
namely other.lua.
-z
Get Wireshark to collect various types of statistics and display the result in a window that
updates in semi-real time.

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Packet colorization
A very useful mechanism available in Wireshark is packet colorization. You can set up Wireshark
so that it will colorize packets according to a display filter. This allows you to emphasize the packets
you might be interested in.
You can find a lot of coloring rule examples at the Wireshark Wiki Coloring Rules page at
https://wiki.wireshark.org/ColoringRules.
There are two types of coloring rules in Wireshark: temporary rules that are only in effect until you
quit the program, and permanent rules that are saved in a preference file so that they are available
the next time you run Wireshark.
Temporary rules can be added by selecting a packet and pressing the Ctrl key together with one of
the number keys. This will create a coloring rule based on the currently selected conversation. It
will try to create a conversation filter based on TCP first, then UDP, then IP and at last Ethernet.
Temporary filters can also be created by selecting the Colorize with Filter › Color X menu items
when right-clicking in the packet detail pane.
To permanently colorize packets, select View › Coloring Rules…. Wireshark will display the
“Coloring Rules” dialog box as shown in The “Coloring Rules” dialog box.

Figure 86. The “Coloring Rules” dialog box

If this is the first time using the Coloring Rules dialog and you’re using the default configuration
profile you should see the default rules, shown above.

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The first match wins

NOTE

More specific rules should usually be listed before more general rules. For example,
if you have a coloring rule for UDP before the one for DNS, the rule for DNS may not
be applied (DNS is typically carried over UDP and the UDP rule will match first).

You can create a new rule by clicking on the [ + ] button. You can delete one or more rules by
clicking the [ - ] button. The “copy” button will duplicate a rule.
You can edit a rule by double-clicking on its name or filter. In The “Coloring Rules” dialog box the
name of the rule “Checksum Errors” is being edited. Clicking on the [ Foreground ] and
[ Background ] buttons will open a color chooser (A color chooser) for the foreground (text) and
background colors respectively.

Figure 87. A color chooser

The color chooser appearance depends on your operating system. The macOS color picker is shown.
Select the color you desire for the selected packets and click [ OK ].
Using color filters with Wireshark shows an example of several color filters being used in
Wireshark. Note that the frame detail shows that the “Bad TCP” rule rule was applied, along with
the matching filter.

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Figure 88. Using color filters with Wireshark

Control Protocol dissection
The user can control how protocols are dissected.
Each protocol has its own dissector, so dissecting a complete packet will typically involve several
dissectors. As Wireshark tries to find the right dissector for each packet (using static “routes” and
heuristics “guessing”), it might choose the wrong dissector in your specific case. For example,
Wireshark won’t know if you use a common protocol on an uncommon TCP port, e.g. using HTTP
on TCP port 800 instead of the standard port 80.
There are two ways to control the relations between protocol dissectors: disable a protocol
dissector completely or temporarily divert the way Wireshark calls the dissectors.

The “Enabled Protocols” dialog box
The Enabled Protocols dialog box lets you enable or disable specific protocols. All protocols are
enabled by default. When a protocol is disabled, Wireshark stops processing a packet whenever
that protocol is encountered.

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Disabling a protocol will prevent information about higher-layer protocols from
being displayed. For example, suppose you disabled the IP protocol and selected a
NOTE

packet containing Ethernet, IP, TCP, and HTTP information. The Ethernet
information would be displayed, but the IP, TCP and HTTP information would not disabling IP would prevent it and the other protocols from being displayed.

To enable or disable protocols select Analyze › Enabled Protocols…. Wireshark will pop up the
“Enabled Protocols” dialog box as shown in The “Enabled Protocols” dialog box.

Figure 89. The “Enabled Protocols” dialog box

To disable or enable a protocol, simply click on it using the mouse or press the space bar when the
protocol is highlighted. Note that typing the first few letters of the protocol name when the Enabled
Protocols dialog box is active will temporarily open a search text box and automatically select the
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first matching protocol name (if it exists).
You must use the [ Save ] button to save your settings. The [ OK ] or [ Apply ] buttons will not save
your changes permanently and they will be lost when Wireshark is closed.
You can choose from the following actions:
1. [ Enable All ]: Enable all protocols in the list.
2. [ Disable All ]: Disable all protocols in the list.
3. [ Invert ]: Toggle the state of all protocols in the list.
4. [ OK ]: Apply the changes and close the dialog box.
5. [ Apply ]: Apply the changes and keep the dialog box open.
6. [ Save ]: Save the settings to the disabled_protos, see Files and Folders for details.
7. [ Cancel ]: Cancel the changes and close the dialog box.

User Specified Decodes
The “Decode As” functionality lets you temporarily divert specific protocol dissections. This might
be useful for example, if you do some uncommon experiments on your network.
Decode As is accessed by selecting the Analyze › Decode As…. Wireshark will pop up the “Decode
As” dialog box as shown in The “Decode As” dialog box.

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Figure 90. The “Decode As” dialog box

The content of this dialog box depends on the selected packet when it was opened.
These settings will be lost if you quit Wireshark or change profile unless you save the entries in the
Show User Specified Decodes… windows (Show User Specified Decodes).
1. [ Decode ]: Decode packets the selected way.
2. [ Do not decode ]: Do not decode packets the selected way.
3. [ Link/Network/Transport ]: Specify the network layer at which “Decode As” should take place.
Which of these pages are available depends on the content of the selected packet when this
dialog box is opened.
4. [ Show Current ]: Open a dialog box showing the current list of user specified decodes.
5. [ OK ]: Apply the currently selected decode and close the dialog box.
6. [ Apply ]: Apply the currently selected decode and keep the dialog box open.
7. [ Cancel ]: Cancel the changes and close the dialog box.

Show User Specified Decodes
This dialog box shows the currently active user specified decodes. These entries can be saved into
current profile for later session.

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Figure 91. The “Decode As: Show” dialog box

1. [ OK ]: Close this dialog box.
2. [ Save ]: Save the entries in the table into current profile.
3. [ Clear ]: Removes all user specified decodes without updating the profile.

Preferences
There are a number of preferences you can set. Simply select the Edit › Preferences… (Wireshark

› Preferences… on macOS) and Wireshark will pop up the Preferences dialog box as shown in The
preferences dialog box, with the “User Interface” page as default. On the left side is a tree where
you can select the page to be shown.
• The [ OK ] button will apply the preferences settings and close the dialog.
• The [ Apply ] button will apply the preferences settings and keep the dialog open.
• The [ Cancel ] button will restore all preferences settings to the last saved state.

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Figure 92. The preferences dialog box

Interface Options
In the “Capture” preferences it is possible to configure several options for the interfaces available
on your computer. Select the “Capture” pane and press the [ Edit ] button. In this window it is
possible to change the default link-layer header type for the interface, add a comment or choose to
hide a interface from other parts of the program.

Figure 93. The interface options dialog box

Each row contains options for each interface available on your computer.

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• Device: the device name provided by the operating system.
• Description: provided by the operating system.
• Default link-layer: each interface may provide several link-layer header types. The default linklayer chosen here is the one used when you first start Wireshark. It is also possible to change
this value in The “Capture Options” dialog box when you start a capture. For a detailed
description, see Link-layer header type.
• Comment: a user provided description of the interface. This comment will be used as a
description instead of the operating system description.
• Hide?: enable this option to hide the interface from other parts of the program.

Configuration Profiles
Configuration Profiles can be used to configure and use more than one set of preferences and
configurations. Select the Edit › Configuration Profiles… menu item or press Shift+Ctrl+A or
Shift+⌘+A (macOS) and Wireshark will pop up the Configuration Profiles dialog box as shown in
The configuration profiles dialog box. It is also possible to click in the “Profile” part of the statusbar
to popup a menu with available Configuration Profiles (The Statusbar with a configuration profile
menu).
Configuration files stored in each profile include:
• Preferences (preferences) (Preferences)
• Capture Filters (cfilters) (Defining and saving filters)
• Display Filters (dfilters) (Defining and saving filters)
• Coloring Rules (colorfilters) (Packet colorization)
• Disabled Protocols (disabled_protos) (The “Enabled Protocols” dialog box)
• User Accessible Tables:
◦ Custom HTTP headers (custom_http_header_fields)
◦ Custom IMF headers (imf_header_fields)
◦ Custom LDAP AttributeValue types (custom_ldap_attribute_types)
◦ Display Filter Macros (dfilter_macros) (Display Filter Macros)
◦ ESS Category Attributes (ess_category_attributes) (ESS Category Attributes)
◦ MaxMind Database Paths (maxmind_db_paths) (MaxMind Database Paths)
◦ K12 Protocols (k12_protos) (Tektronix K12xx/15 RF5 protocols Table)
◦ Object Identifier Names and Associated Syntaxes (Object Identifiers)
◦ PRES Users Context List (pres_context_list) (PRES Users Context List)
◦ SCCP Users Table (sccp_users) (SCCP users Table)

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◦ SNMP Enterprise Specific Trap Types (snmp_specific_traps) (SNMP Enterprise Specific Trap
Types)
◦ SNMP Users (snmp_users) (SNMP users Table)
◦ User DLTs Table (user_dlts) (User DLTs protocol table)
◦ IKEv2 decryption table (ikev2_decryption_table) (IKEv2 decryption table)
• Changed dissector assignments (decode_as_entries), which can be set in the “Decode As…” dialog
box (User Specified Decodes), and further saved in the “User Specified Decodes…” window
(Show User Specified Decodes).
• Some recent settings (recent), such as pane sizes in the Main window (The Main window),
column widths in the packet list (The “Packet List” Pane), all selections in the View menu (The
“View” Menu) and the last directory navigated to in the “File Open” dialog.
All other configurations are stored in the personal configuration folder and are common to all
profiles.

Figure 94. The configuration profiles dialog box

New (+)
Create a new profile. The name of the created profile is “New profile” and is highlighted so that
you can more easily change it.
Delete (-)
Deletes the selected profile. This includes all configuration files used in this profile. It is not
possible to delete the “Default” profile or global profiles.
Copy
Copies the selected profile. This copies the configuration of the profile currently selected in the
list. The name of the created profile is the same as the copied profile, with the text “(copy)” and
is highlighted so that you can more easily change it.
[ OK ]

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This button saves all changes, applies the selected profile and closes the dialog.
[ Cancel ]
Close this dialog. This will discard unsaved settings, new profiles will not be added and deleted
profiles will not be deleted.
[ Help ]
Show this help page.

User Table
The User Table editor is used for managing various tables in wireshark. Its main dialog works very
similarly to that of Packet colorization.

Display Filter Macros
Display Filter Macros are a mechanism to create shortcuts for complex filters. For example defining
a display filter macro named tcp_conv whose text is ( (ip.src == $1 and ip.dst == $2 and tcp.srcport ==
$3 and tcp.dstport == $4) or (ip.src == $2 and ip.dst == $1 and tcp.srcport == $4 and tcp.dstport == $3)
) would allow to use a display filter like ${tcp_conv:10.1.1.2;10.1.1.3;1200;1400} instead of typing the
whole filter.
Display Filter Macros can be managed with a User Table by selecting Analyze › Display Filter
Macros from the menu. The User Table has the following fields
Name
The name of the macro.
Text
The replacement text for the macro it uses $1, $2, $3, … as the input arguments.

ESS Category Attributes
Wireshark uses this table to map ESS Security Category attributes to textual representations. The
values to put in this table are usually found in a XML SPIF, which is used for defining security
labels.
This table is handled by an User Table with the following fields.
Tag Set
An Object Identifier representing the Category Tag Set.
Value
The value (Label And Cert Value) representing the Category.

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Name
The textual representation for the value.

MaxMind Database Paths
If your copy of Wireshark supports MaxMind’s MaxMindDB library, you can use their databases to
match IP addresses to countries, cites, autonomous system numbers, and other bits of information.
Some databases are available at no cost, while others require a licensing fee. See the MaxMind web
site for more information.
This table is handled by an User Table with the following fields.
Database pathname
This specifies a directory containing MaxMind data files. Any files ending with .mmdb will be
automatically loaded.
The locations for your data files are up to you, but /usr/share/GeoIP and /var/lib/GeoIP are
common on Linux and C:\ProgramData\GeoIP, C:\Program Files\Wireshark\GeoIP might be good
choices on Windows.
Previous versions of Wireshark supported MaxMind’s original GeoIP Legacy database format. They
were configured similar to MaxMindDB files above, except GeoIP files must begin with Geo and end
with .dat. They are no longer supported and MaxMind stopped distributing GeoLite Legacy
databases in April 2018.

IKEv2 decryption table
Wireshark can decrypt Encrypted Payloads of IKEv2 (Internet Key Exchange version 2) packets if
necessary information is provided. Note that you can decrypt only IKEv2 packets with this feature.
If you want to decrypt IKEv1 packets or ESP packets, use Log Filename setting under ISAKMP
protocol preference or settings under ESP protocol preference respectively.
This table is handled by an User Table with the following fields.
Initiator’s SPI
Initiator’s SPI of the IKE_SA. This field takes hexadecimal string without “0x” prefix and the
length must be 16 hex chars (represents 8 octets).
Responder’s SPI
Responder’s SPI of the IKE_SA. This field takes hexadecimal string without “0x” prefix and the
length must be 16 hex chars (represents 8 octets).
SK_ei
Key used to encrypt/decrypt IKEv2 packets from initiator to responder. This field takes
hexadecimal string without “0x” prefix and its length must meet the requirement of the

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encryption algorithm selected.
SK_er
Key used to encrypt/decrypt IKEv2 packets from responder to initiator. This field takes
hexadecimal string without “0x” prefix and its length must meet the requirement of the
encryption algorithm selected.
Encryption Algorithm
Encryption algorithm of the IKE_SA.
SK_ai
Key used to calculate Integrity Checksum Data for IKEv2 packets from responder to initiator.
This field takes hexadecimal string without “0x” prefix and its length must meet the requirement
of the integrity algorithm selected.
SK_ar
Key used to calculate Integrity Checksum Data for IKEv2 packets from initiator to responder.
This field takes hexadecimal string without “0x” prefix and its length must meet the requirement
of the integrity algorithm selected.
Integrity Algorithm
Integrity algorithm of the IKE_SA.

Object Identifiers
Many protocols that use ASN.1 use Object Identifiers (OIDs) to uniquely identify certain pieces of
information. In many cases, they are used in an extension mechanism so that new object identifiers
(and associated values) may be defined without needing to change the base standard.
Whilst Wireshark has knowledge about many of the OIDs and the syntax of their associated values,
the extensibility means that other values may be encountered.
Wireshark uses this table to allow the user to define the name and syntax of Object Identifiers that
Wireshark does not know about (for example, a privately defined X.400 extension). It also allows
the user to override the name and syntax of Object Identifiers that Wireshark does know about (e.g.
changing the name “id-at-countryName” to just “c”).
This table is handled by an User Table with the following fields.
OID
The string representation of the Object Identifier e.g. “2.5.4.6”.
Name
The name that should be displayed by Wireshark when the Object Identifier is dissected e.g.
(“c”);

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Syntax
The syntax of the value associated with the Object Identifier. This must be one of the syntaxes
that Wireshark already knows about (e.g. “PrintableString”).

PRES Users Context List
Wireshark uses this table to map a presentation context identifier to a given object identifier when
the capture does not contain a PRES package with a presentation context definition list for the
conversation.
This table is handled by an User Table with the following fields.
Context Id
An Integer representing the presentation context identifier for which this association is valid.
Syntax Name OID
The object identifier representing the abstract syntax name, which defines the protocol that is
carried over this association.

SCCP users Table
Wireshark uses this table to map specific protocols to a certain DPC/SSN combination for SCCP.
This table is handled by an User Table with the following fields.
Network Indicator
An Integer representing the network indicator for which this association is valid.
Called DPCs
An range of integers representing the dpcs for which this association is valid.
Called SSNs
An range of integers representing the ssns for which this association is valid.
User protocol
The protocol that is carried over this association

SMI (MIB and PIB) Modules
If your copy of Wireshark supports libSMI, you can specify a list of MIB and PIB modules here. The
COPS and SNMP dissectors can use them to resolve OIDs.
Module name
The name of the module, e.g. IF-MIB.

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SMI (MIB and PIB) Paths
If your copy of Wireshark supports libSMI, you can specify one or more paths to MIB and PIB
modules here.
Directory name
A module directory, e.g. /usr/local/snmp/mibs. Wireshark automatically uses the standard SMI
path for your system, so you usually don’t have to add anything here.

SNMP Enterprise Specific Trap Types
Wireshark uses this table to map specific-trap values to user defined descriptions in a Trap PDU.
The description is shown in the packet details specific-trap element.
This table is handled by an User Table with the following fields.
Enterprise OID
The object identifier representing the object generating the trap.
Trap Id
An Integer representing the specific-trap code.
Description
The description to show in the packet details.

SNMP users Table
Wireshark uses this table to verify authentication and to decrypt encrypted SNMPv3 packets.
This table is handled by an User Table with the following fields.
Engine ID
If given this entry will be used only for packets whose engine id is this. This field takes an
hexadecimal string in the form 0102030405.
Username
This is the userName. When a single user has more than one password for different SNMPengines the first entry to match both is taken, if you need a catch all engine-id (empty) that entry
should be the last one.
Authentication model
Which auth model to use (either “MD5” or “SHA1”).
Password
The authentication password. Use \xDD for unprintable characters. An hexadecimal password
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must be entered as a sequence of \xDD characters. For example the hex password 010203040506
must be entered as \x01\x02\x03\x04\x05\x06. The \ character must be treated as an unprintable
character, i.e. it must be entered as \x5C or \x5c.
Privacy protocol
Which encryption algorithm to use (either “DES” or “AES”).
Privacy password
The privacy password. Use \xDD for unprintable characters. An hexadecimal password must be
entered as a sequence of \xDD characters. For example the hex password 010203040506 must be
entered as \x01\x02\x03\x04\x05\x06. The \ character must be treated as an unprintable character,
i.e. it must be entered as \x5C or \x5c.

Tektronix K12xx/15 RF5 protocols Table
The Tektronix K12xx/15 rf5 file format uses helper files (*.stk) to identify the various protocols that
are used by a certain interface. Wireshark doesn’t read these stk files, it uses a table that helps it
identify which lowest layer protocol to use.
Stk file to protocol matching is handled by an User Table with the following fields.
Match string
A partial match for an stk filename, the first match wins, so if you have a specific case and a
general one the specific one must appear first in the list.
Protocol
This is the name of the encapsulating protocol (the lowest layer in the packet data) it can be
either just the name of the protocol (e.g. mtp2, eth_witoutfcs, sscf-nni ) or the name of the
encapsulation protocol and the “application” protocol over it separated by a colon (e.g sscop:sscfnni, sscop:alcap, sscop:nbap, …)

User DLTs protocol table
When a pcap file uses one of the user DLTs (147 to 162) wireshark uses this table to know which
protocol(s) to use for each user DLT.
This table is handled by an User Table with the following fields.
DLT
One of the user dlts.
Payload protocol
This is the name of the payload protocol (the lowest layer in the packet data). (e.g. “eth” for
ethernet, “ip” for IPv4)

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Header size
If there is a header protocol (before the payload protocol) this tells which size this header is. A
value of 0 disables the header protocol.
Header protocol
The name of the header protocol to be used (uses “data” as default).
Trailer size
If there is a trailer protocol (after the payload protocol) this tells which size this trailer is. A value
of 0 disables the trailer protocol.
Trailer protocol
The name of the trailer protocol to be used (uses “data” as default).

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MATE
Introduction
MATE: Meta Analysis and Tracing Engine
What is MATE? Well, to keep it very short, with MATE you can create user configurable extension(s)
of the display filter engine.
MATE’s goal is to enable users to filter frames based on information extracted from related frames
or information on how frames relate to each other. MATE was written to help troubleshooting
gateways and other systems where a "use" involves more protocols. However MATE can be used as
well to analyze other issues regarding a interaction between packets like response times,
incompleteness of transactions, presence/absence of certain attributes in a group of PDUs and
more.
MATE is a Wireshark plugin that allows the user to specify how different frames are related to each
other. To do so, MATE extracts data from the frames' tree and then, using that information, tries to
group the frames based on how MATE is configured. Once the PDUs are related MATE will create a
"protocol" tree with fields the user can filter with. The fields will be almost the same for all the
related frames, so one can filter a complete session spanning several frames containing more
protocols based on an attribute appearing in some related frame. Other than that MATE allows to
filter frames based on response times, number of PDUs in a group and a lot more.
So far MATE has been used to:
• Filter all packets of a call using various protocols knowing just the calling number. (MATE’s
original goal)
• Filter all packets of all calls using various protocols based on the release cause of one of its
"segments".
• Extrapolate slow transactions from very "dense" captures. (finding requests that timeout)
• Find incomplete transactions (no responses)
• Follow requests through more gateways/proxies.
• more…

Getting Started
These are the steps to try out MATE:
• Run Wireshark and check if the plugin is installed correct (MATE should appear in
Help→About→Plugins)
• Get a configuration file e.g. tcp.mate (see Mate/Examples for more) and place it somewhere on

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your harddisk.
• Go to Preferences→Protocols→MATE and set the config filename to the file you want to use (you
don’t have to restart Wireshark)
• Load a corresponding capture file (e.g. http.cap) and see if MATE has added some new display
filter fields, something like: mate tcp_pdu:1->tcp_ses:1 or, at prompt: path_to/wireshark -o
"mate.config: tcp.mate" -r http.cap.
If anything went well, your packet details might look something like this:

MATE Manual
Introduction
MATE creates a filterable tree based on information contained in frames that share some
relationship with information obtained from other frames. The way this relationships are made is
described in a configuration file. The configuration file tells MATE what makes a PDU and how to
relate it to other PDUs.
MATE analyzes each frame to extract relevant information from the "protocol" tree of that frame.
The extracted information is contained in MATE PDUs; these contain a list of relevant attributes
taken from the tree. From now on, I will use the term "PDU" to refer to the objects created by MATE
containing the relevant information extracted from the frame; I’ll use "frame" to refer to the "raw"
information extracted by the various dissectors that pre-analyzed the frame.
For every PDU, MATE checks if it belongs to an existing "Group of PDUs" (Gop). If it does, it assigns
the PDU to that Gop and moves any new relevant atributes to the Gop’s attribute list. How and
when do PDUs belong to Gops is described in the configuration file as well.
Every time a Gop is assigned a new PDU, MATE will check if it matches the conditions to make it

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belong to a "Group of Groups" (Gog). Naturally the conditions that make a Gop belong to a Gog are
taken from the configuration file as well.
Once MATE is done analyzing the frame it will be able to create a "protocol" tree for each frame
based on the PDUs, the Gops they belong to and naturally any Gogs the former belongs to.
How to tell MATE what to extract, how to group it and then how to relate those groups is made
using AVPs and AVPLs.
Information in MATE is contained in Attribute/Value Pairs (AVPs). AVPs are made of two strings: the
name and the value. AVPs are used in the configuration and there they have an operator as well.
There are various ways AVPs can be matched against each other using those operators.
AVPs are grouped into AVP Lists (AVPLs). PDUs, Gops and Gogs have an AVPL each. Their AVPLs will
be matched in various ways against others coming from the configuration file.
MATE will be instructed how to extract AVPs from frames in order to create a PDU with an AVPL. It
will be instructed as well, how to match that AVPL against the AVPLs of other similar PDUs in order
to relate them. In MATE the relationship between PDUs is a Gop, it has an AVPL as well. MATE will
be configured with other AVPLs to operate against the Gop’s AVPL to relate Gops together into Gogs.
A good understanding on how AVPs and AVPLs work is fundamental to understand how MATE
works.

Attribute Value Pairs
Information used by MATE to relate different frames is contained in Attribute/ Value Pairs (AVPs).
AVPs are made of two strings - the name and the value. When AVPs are used in the configuration,
an operator is defined as well. There are various ways AVPs can be matched against each other
using those operators.

avp_name="avp's value"
another_name= "1234 is the value"
The name is a string used to refer to a "kind" of an AVP. Two AVPs won’t match unless their names
are identical.
You should not use uppercase characters in names, or names that start with . or _. Capitalized
names are reserved for configuration parameters (we’ll call them keywords); nothing forbids you
from using capitalized strings for other things as well but it probably would be confusing. I’ll avoid
using capitalized words for anything but the keywords in this document, the reference manual, the
examples and the base library. Names that start with a . would be very confusing as well because in
the old grammar, AVPL transformations use names starting with a . to indicate they belong to the
replacement AVPL.
The value is a string that is either set in the configuration (for configuration AVPs) or by wireshark

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while extracting interesting fields from a frame’s tree. The values extracted from fields use the
same representation as they do in filter strings except that no quotes are used.
The name can contain only alphanumeric characters, "_", and ".". The name ends with an operator.
The value will be dealt with as a string even if it is a number. If there are any spaces in the value,
the value must be between quotes "".

ip_addr=10.10.10.11,
tcp_port=1234,
binary_data=01:23:45:67:89:ab:cd:ef,
parameter12=0x23aa,
parameter_with_spaces="this value has spaces"
The way two AVPs with the same name might match is described by the operator. Remember two
AVPs won’t match unless their names are identical. In MATE, match operations are always made
between the AVPs extracted from frames (called data AVPs) and the configuration’s AVPs.
Currently defined MATE’s AVP match operators are:
• Equal = will match if the string given completely matches the data AVP’s value string
• Not Equal ! will match only if the given value string is not equal to the data AVP’s value string
• One Of {} will match if one of the possible strings listed is equal to the data AVP’s value string
• Starts With ^ will match if the string given matches the first characters of the data AVP’s value
string
• Ends With $ will match if the string given matches the last characters of the data AVP’s value
string
• Contains ~ will match if the string given matches any substring of the data AVP’s value string
• Lower Than < will match if the data AVP’s value string is semantically lower than the string
given
• Higher Than > will match if the data AVP’s value string is semantically higher than the string
given
• Exists ? (the ? can be ommited) will match as far as a data AVP of the given name exists

AVP lists
An AVPL is a set of diverse AVPs that can be matched against other AVPLs. Every PDU, Gop and Gog
has an AVPL that contains the information regarding it. The rules that MATE uses to group Pdus and
Gops are AVPL operations.
There will never be two identical AVPs in a given AVPL. However, we can have more than one AVP
with the same name in an AVPL as long as their values are different.

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Some AVPL examples:

( addr=10.20.30.40, addr=192.168.0.1, tcp_port=21, tcp_port=32534, user_cmd=PORT,
data_port=12344, data_addr=192.168.0.1 )
( addr=10.20.30.40, addr=192.168.0.1, channel_id=22:23, message_type=Setup,
calling_number=1244556673 )
( addr=10.20.30.40, addr=192.168.0.1, ses_id=01:23:45:67:89:ab:cd:ef )
( user_id=pippo, calling_number=1244556673, assigned_ip=10.23.22.123 )
In MATE there are two types of AVPLs:
• data AVPLs that contain information extracted from frames.
• operation AVPLs that come from the configuration and are used to tell MATE how to relate
items based on their data AVPLs.
Data AVPLs can be operated against operation AVPLs in various ways:
• Loose Match: Will match if at least one of the AVPs of each AVPL match. If it matches it will
return an AVPL containing all AVPs from the operand AVPL that did match the operator’s AVPs.
• "Every" Match: Will match if none of the AVPs of the operator AVPL fails to match a present AVP
in the operand AVPL, even if not all of the operator’s AVPs have a match. If it matches it will
return an AVPL containing all AVPs from the operand AVPL that did match one AVP in the
operator AVPL.
• Strict Match: Will match if and only if every one of the operator’s AVPs have at least one match
in the operand AVPL. If it matches it will return an AVPL containing the AVPs from the operand
that matched.
• There’s also a Merge operation that is to be performed between AVPLs where all the AVPs that
don’t exist in the operand AVPL but exist in the operand will be added to the operand AVPL.
• Other than that there are Transformations - a combination of a match AVPL and an AVPL to
merge.

MATE Analysis
MATE’s analysis of a frame is performed in three phases:
• In the first phase, MATE attempts to extract a MATE Pdu from the frame’s protocol tree. MATE
will create a Pdu if MATE’s config has a Pdu declaration whose Proto is contained in the frame.
• In the second phase, if a Pdu has been extracted from the frame, MATE will try to group it to
other Pdus into a Gop (Group of Pdus) by matching the key criteria given by a Gop declaration. If
there is no Gop yet with the key criteria for the Pdu, MATE will try to create a new Gop for it if it
matches the Start criterium given in the Gop declaration.
• In the third phase, if there’s a Gop for the Pdu, MATE will try to group this Gop with other Gops

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into a Gog (Group of Groups) using the criteria given by the Member criteria of a Gog declaration.

The extraction and matching logic comes from MATE’s configuration; MATE’s configuration file is
declared by the mate.config preference. By default it is an empty string which means: do not
configure MATE.
The config file tells MATE what to look for in frames; How to make PDUs out of it; How will PDUs be
related to other similar PDUs into Gops; And how Gops relate into Gogs.
The MATE configuration file is a list of declarations. There are 4 types of declarations: Transform,
Pdu, Gop and Gog.

206

Mate’s PDU’s
MATE will look in the tree of every frame to see if there is useful data to extract, and if there is, it
will create one or more PDU objects containing the useful information.
The first part of MATE’s analysis is the "PDU extraction"; there are various "Actions" that are used to
instruct MATE what has to be extracted from the current frame’s tree into MATE’s PDUs.
PDU data extraction

MATE will make a Pdu for each different proto field of Proto type present in the frame. MATE will
fetch from the field’s tree those fields that are defined in the Pdsu’s configuration actions
declaration whose initial offset in the frame is within the boundaries of the current Proto and those
of the given Transport and Payload statements.

Pdu dns_pdu
Extract
Extract
Extract
};

Proto dns Transport ip {
addr From ip.addr;
dns_id From dns.id;
dns_resp From dns.flags.response;

MATE will make a Pdu for each different proto field of Proto type present in the frame. MATE will
fetch from the field’s tree those fields that are defined in the Pdsu’s configuration actions AVPL
whose initial offset in the frame is within the boundaries of the current Proto and those of the
various assigned Transports.

Once MATE has found a Proto field for which to create a Pdu from the frame it will move
backwards in the frame looking for the respective Transport fields. After that it will create AVPs
named as each of those given in the rest of the AVPL for every instance of the fields declared as its

207

values.

Sometimes we need information from more than one Transport protocol. In that case MATE will
check the frame looking backwards to look for the various Transport protocols in the given stack.
MATE will choose only the closest transport boundary per "protocol" in the frame.
This way we’ll have all Pdus for every Proto that appears in a frame match its relative transports.

Pdu isup_pdu Proto isup Transport mtp3/ip {
Extract m3pc From mtp3.dpc;
Extract m3pc From mtp3.opc;
Extract cic From isup.cic;
Extract addr From ip.addr;
Extract isup_msg From isup.message_type;
};

This allows to assign the right Transport to the Pdu avoiding duplicate transport protocol entries (in
case of tunneled ip over ip for example).

208

Pdu ftp_pdu Proto ftp Transport tcp/ip {
Extract addr From ip.addr;
Extract port From tcp.port;
Extract ftp_cmd From ftp.command;
};

Other than the mandatory Transport there is also an optional Payload statement, which works pretty
much as Transport but refers to elements after the Proto's range. It is useful in those cases where the
payload protocol might not appear in a Pdu but nevertheless the Pdu belongs to the same category.

Pdu mmse_over_http_pdu Proto http Transport tcp/ip {
Payload mmse;
Extract
Extract
Extract
Extract
Extract
Extract
Extract
Extract
Extract
Extract
Extract

addr From ip.addr;
port From tcp.port;
method From http.request.method;
content From http.content_type;
http_rq From http.request;
resp From http.response.code;
host From http.host;
trx From mmse.transaction_id;
msg_type From mmse.message_type;
notify_status From mmse.status;
send_status From mmse.response_status;

};

209

Conditions on which to create PDUs

There might be cases in which we won’t want MATE to create a PDU unless some of its extracted
attributes meet or do not meet some criteria. For that we use the Criteria statements of the Pdu
declarations.

Pdu isup_pdu Proto isup Transport mtp3/ip {
...
// MATE will create isup_pdu PDUs only when there is not a point code '1234'
Criteria Reject Strict (m3pc=1234);
};
Pdu ftp_pdu Proto ftp Transport tcp/ip {
...
// MATE will create ftp_pdu PDUs only when they go to port 21 of our ftp_server
Criteria Accept Strict (addr=10.10.10.10, port=21);
};
The Criteria statement is given an action (Accept or Reject), a match mode (Strict, Loose or Every)
and an AVPL against which to match the currently extracted one.
Transforming the attributes of a PDU

Once the fields have been extracted into the Pdu’s AVPL, MATE will apply any declared
transformation to it. The way transforms are applied and how they work is described later on.
However it’s useful to know that once the AVPL for the Pdu is created, it may be transformed before
being analyzed. That way we can massage the data to simplify the analysis.
MATE’s PDU tree

Every successfully created Pdu will add a MATE tree to the frame dissection. If the Pdu is not
related to any Gop, the tree for the Pdu will contain just the Pdu’s info, if it is assigned to a Gop, the
tree will also contain the Gop items, and the same applies for the Gog level.

mate dns_pdu:1
dns_pdu: 1
dns_pdu time: 3.750000
dns_pdu Attributes
dns_resp: 0
dns_id: 36012
addr: 10.194.4.11
addr: 10.194.24.35
The Pdu’s tree contains some filterable fields
210

• mate.dns_pdu will contain the number of the "dns_pdu" Pdu
• mate.dns_pdu.RelativeTime will contain the time passed since the beginning of the capture in
seconds
• the tree will contain the various attributes of the Pdu as well, these will all be strings (to be used
in filters as "10.0.0.1", not as 10.0.0.1)
◦ mate.dns_pdu.dns_resp
◦ mate.dns_pdu.dns_id
◦ mate.dns_pdu.addr
Grouping Pdus together (Gop)
Once MATE has created the Pdus it passes to the Pdu analysis phase. During the PDU analysis phase
MATE will try to group Pdus of the same type into Groups of Pdus (aka *Gop*s) and copy some AVPs
from the Pdu’s AVPL to the Gop’s AVPL.

What can belong to a Gop

Given a Pdu, the first thing MATE will do is to check if there is any Gop declaration in the
configuration for the given Pdu type. If so, it will use its Match AVPL to match it against the Pdu’s
AVPL; if they don’t match, the analysis phase is done. If there is a match, the AVPL is the Gop’s
candidate key which will be used to search the Gop’s index for the Gop to which to assign the
current PDU. If there is no such Gop and this Pdu does not match the Start criteria of a Gop
declaration for the Pdu type, the Pdu will remain unassigned and only the analysis phase will be
done.

211

Gop ftp_ses On ftp_pdu Match (addr, addr, port, port);
Gop dns_req On dns_pdu Match (addr, addr, dns_id);
Gop isup_leg On isup_pdu Match (m3pc, m3pc, cic);

Start of a Gop

If there was a match, the candidate key will be used to search the Gop’s index to see if there is
already a Gop matching the Gop’s key the same way. If there is such a match in the Gops collection,
and the PDU doesn’t match the Start AVPL for its kind, the PDU will be assigned to the matching
Gop. If it is a Start match, MATE will check whether or not that Gop has been already stopped. If the
Gop has been stopped, a new Gop will be created and will replace the old one in the Gop’s index.

Gop ftp_ses On ftp_pdu Match (addr, addr, port, port) {
Start (ftp_cmd=USER);
};
Gop dns_req On dns_pdu Match (addr, addr, dns_id) {
Start (dns_resp=0);
};
Gop isup_leg On isup_pdu Match (m3pc, m3pc, cic) {
Start (isup_msg=1);
};
If no Start is given for a Gop, a Pdu whose AVPL matches an existing Gog’s key will act as the start
of a Gop.
What goes into the Gop’s AVPL

Once we know a Gop exists and the Pdu has been assigned to it, MATE will copy into the Gop’s AVPL
all the attributes matching the key plus any AVPs of the Pdu’s AVPL matching the Extra AVPL.

Gop ftp_ses On ftp_pdu Match (addr, addr, port, port) {
Start (ftp_cmd=USER);
Extra (pasv_prt, pasv_addr);
};
Gop isup_leg On isup_pdu Match (m3pc, m3pc, cic) {
Start (isup_msg=1);
Extra (calling, called);
};

212

End of a Gop

Once the Pdu has been assigned to the Gop, MATE will check whether or not the Pdu matches the
Stop, if it happens, MATE will mark the Gop as stopped. Even after stopped, a Gop may get assigned
new Pdus matching its key, unless such Pdu matches Start. If it does, MATE will instead create a
new Gop starting with that Pdu.

Gop ftp_ses On ftp_pdu Match (addr, addr, port, port) {
Start (ftp_cmd=USER);
Stop (ftp_cmd=QUIT); // The response to the QUIT command will be assigned to the
same Gop
Extra (pasv_prt, pasv_addr);
};
Gop dns_req On dns_pdu Match (addr, addr, dns_id) {
Start (dns_resp=0);
Stop (dns_resp=1);
};
Gop isup_leg On isup_pdu Match (m3pc, m3pc, cic) {
Start (isup_msg=1); // IAM
Stop (isup_msg=16); // RLC
Extra (calling, called);
};
If no Stop criterium is stated for a given Gop, the Gop will be stopped as soon as it is created.
However, as with any other Gop, Pdus matching the Gop’s key will still be assigned to the Gop
unless they match a Start condition, in which case a new Gop using the same key will be created.
Gop’s tree
For every frame containing a Pdu that belongs to a Gop, MATE will create a tree for that Gop.
The example below represents the tree created by the dns_pdu and dns_req examples.

213

...
mate dns_pdu:6->dns_req:1
dns_pdu: 6
dns_pdu time: 2.103063
dns_pdu time since begining of Gop: 2.103063
dns_req: 1
dns_req Attributes
dns_id: 36012
addr: 10.194.4.11
addr: 10.194.24.35
dns_req Times
dns_req start time: 0.000000
dns_req hold time: 2.103063
dns_req duration: 2.103063
dns_req number of PDUs: 2
Start PDU: in frame 1
Stop PDU: in frame 6 (2.103063 : 2.103063)
dns_pdu Attributes
dns_resp: 1
dns_id: 36012
addr: 10.194.4.11
addr: 10.194.24.35
Other than the pdu’s tree, this one contains information regarding the relationship between the
Pdus that belong to the Gop. That way we have:
• mate.dns_req which contains the id of this dns_req Gop. This will be present in frames that
belong to dns_req Gops.
• mate.dns_req.dns_id and mate.dns_req.addr which represent the values of the attributes copied
into the Gop.
• the timers of the Gop
◦ mate.dns_req.StartTime time (in seconds) passed since beginning of capture until Gop’s
start.
◦ mate.dns_req.Time time passed between the start Pdu and the stop Pdu assigned to this Gop
(only created if a Stop criterion has been declared for the Gop and a matching Pdu has
arrived).
◦ mate.dns_req.Duration time passed between the start Pdu and the last Pdu assigned to this
Gop.
• mate.dns_req.NumOfPdus the number of Pdus that belong to this Gop
◦ a filterable list of frame numbers of the pdus of this Gop

214

Gop’s timers

Note that there are two "timers" for a Gop:
• Time, which is defined only for Gops that have been Stopped, and gives the time passed
between the Start and the Stop Pdus.
• Duration, which is defined for every Gop regardles of its state, and give the time passed
between its Start Pdu and the last Pdu that was assigned to that Gop.
So:
• we can filter for Pdus that belong to Gops that have been Stopped with mate.xxx.Time
• we can filter for Pdus that belong to unstopped Gops with mate.xxx && mate.xxx.Time
• we can filter for Pdus that belong to stopped Gops using mate.xxx.Duration
• we can filter for Pdus that belong to Gops that have taken more (or less) time that 0.5s to
complete with mate.xxx.Time > 0.5 (you can try these also as color filters to find out when
response times start to grow)
Grouping Gops together (Gog)
When Gops are created, or whenever their AVPL changes, Gops are (re)analyzed to check if they
match an existent group of groups (Gog) or can create a new one. The Gop analysis is divided into
two phases. In the first phase, the still unassigned Gop is checked to verify whether it belongs to an
already existing Gog or may create a new one. The second phase eventually checks the Gog and
registers its keys in the Gogs index.

215

There are several reasons for the author to believe that this feature needs to be reimplemented, so
probably there will be deep changes in the way this is done in the near future. This section of the
documentation reflects the version of MATE as of wireshark 0.10.9; in future releases this will
change.

216

Declaring a Group Of Groups

The first thing we have to do configuring a Gog is to tell MATE that it exists.

Gog web_use {
...
};

Telling MATE what could be a Gog member

Then we have to tell MATE what to look for a match in the candidate Gops.

Gog web_use {
Member http_ses (host);
Member dns_req (host);
};

Getting interesting data into the Gop

Most often, also other attributes than those used for matching would be interesting. In order to
copy from Gop to Gog other interesting attributes, we might use Extra like we do for Gops.

Gog web_use {
...
Extra (cookie);
};

Gog’s tree

217

mate http_pdu:4->http_req:2->http_use:1
http_pdu: 4
http_pdu time: 1.309847
http_pdu time since begining of Gop: 0.218930
http_req: 2
... (the gop's tree for http_req: 2) ..
http_use: 1
http_use Attributes
host: www.example.com
http_use Times
http_use start time: 0.000000
http_use duration: 1.309847
number of GOPs: 3
dns_req: 1
... (the gop's tree for dns_req: 1) ..
http_req: 1
... (the gop's tree for http_req: 1) ..
http_req of current frame: 2
We can filter on:
• mate.http_use.Duration time elapsed between the first frame of a Gog and the last one
assigned to it.
• the attributess passed to the Gog
◦ mate.http_use.host
AVPL Transforms
A Transform is a sequence of Match rules optionally completed with modification of the match
result by an additional AVPL. Such modification may be an Insert (merge) or a Replace. Transforms
can be used as helpers to manipulate an item’s AVPL before it is processed further. They come to be
very helpful in several cases.
Syntax

AVPL Transformations are declared in the following way:

Transform name {
Match [Strict|Every|Loose] match_avpl [Insert|Replace] modify_avpl ;
...
};
The name is the handle to the AVPL transformation. It is used to refer to the transform when
invoking it later.

218

The Match declarations instruct MATE what and how to match against the data AVPL and how to
modify the data AVPL if the match succeeds. They will be executed in the order they appear in the
config file whenever they are invoked.
The optional match mode qualifier (Strict, Every, or Loose) is used to choose the match mode as
explained above; Strict is a default value which may be omitted.
The optional modification mode qualifier instructs MATE how the modify AVPL should be used:
• the default value Insert (which may be omitted) causes the modify_avpl to be merged to the
existing data AVPL,
• the Replace causes all the matching AVPs from the data AVPL to be replaced by the modify_avpl.
The modify_avpl may be an empty one; this comes useful in some cases for both Insert and Replace
modification modes.
Examples:

Transform insert_name_and {
Match Strict (host=10.10.10.10, port=2345) Insert (name=JohnDoe);
};
adds name=JohnDoe to the data AVPL if it contains host=10.10.10.10 and port=2345

Transform insert_name_or {
Match Loose (host=10.10.10.10, port=2345) Insert (name=JohnDoe);
};
adds name=JohnDoe to the data AVPL if it contains host=10.10.10.10 or port=2345

Transform replace_ip_address {
Match (host=10.10.10.10) Replace (host=192.168.10.10);
};
replaces the original host=10.10.10.10 by host=192.168.10.10

Transform add_ip_address {
Match (host=10.10.10.10) (host=192.168.10.10);
};
adds (inserts) host=192.168.10.10 to the AVPL, keeping the original host=10.10.10.10 in it too

219

Transform replace_may_be_surprising {
Match Loose (a=aaaa, b=bbbb) Replace (c=cccc, d=dddd);
};
gives the following results:
• (a=aaaa, b=eeee) gets transformed to (b=eeee, c=cccc, d=dddd) because a=aaaa did match so it
got replaced while b=eeee did not match so it has been left intact,
• (a=aaaa, b=bbbb) gets transformed to (c=cccc, d=dddd) because both a=aaaa and b=bbbb did
match.
Usage

Once declared, Transforms can be added to the declarations of PDUs, Gops or Gogs. This is done by
adding the Transform name_list statement to the declaration:

Pdu my_proto_pdu Proto my_proto Transport ip {
Extract addr From ip.addr;
...
Transform my_pdu_transform[, other_pdu_transform[, yet_another_pdu_transform]];
};
• In case of PDU, the list of transforms is applied against the PDU’s AVPL after its creation.
• In case of Gop and Gog, the list of transforms is applied against their respective AVPLs when
they are created and every time they change.
Operation

220

• A list of previously declared Transforms may be given to every Item (Pdu, Gop, or Gog), using
the Transform statement.
• Every time the AVPL of an item changes, it will be operated against all the Transforms on the
list given to that item. The Transforms on the list are applied left to right.
• Inside each of the Transforms, the item’s AVPL will be operated against the Transform’s Match
clauses starting from the topmost one, until all have been tried or until one of them succeeds.
MATE’s Transforms can be used for many different things, like:
Multiple Start/Stop conditions for a Gop

Using Transforms we can add more than one start or stop condition to a Gop.

Transform start_cond {
Match (attr1=aaa,attr2=bbb) (msg_type=start);
Match (attr3=www,attr2=bbb) (msg_type=start);
Match (attr5^a) (msg_type=stop);
Match (attr6$z) (msg_type=stop);
};
Pdu pdu ... {
...
Transform start_cond;
}
Gop gop ... {
Start (msg_type=start);
Stop (msg_type=stop);
...
}

Marking Gops and Gogs to filter them easily

Transform marks {
Match (addr=10.10.10.10, user=john) (john_at_host);
Match (addr=10.10.10.10, user=tom) (tom_at_host);
}
...
Gop my_gop ... {
...
Transform marks;
}

221

After that we can use a display filter mate.gop.john_at_host or mate.gop.tom_at_host
Adding direction knowledge to MATE

Transform direction_as_text {
Match (src=192.168.0.2, dst=192.168.0.3) Replace (direction=from_2_to_3);
Match (src=192.168.0.3, dst=192.168.0.2) Replace (direction=from_3_to_2);
};
Pdu my_pdu Proto my_proto Transport tcp/ip {
Extract src From ip.src;
Extract dst From ip.dst;
Extract addr From ip.addr;
Extract port From tcp.port;
Extract start From tcp.flags.syn;
Extract stop From tcp.flags.fin;
Extract stop From tcp.flags.rst;
Transform direction_as_text;
}
Gop my_gop On my_pdu Match (addr,addr,port,port) {
...
Extra (direction);
}

NAT

NAT can create problems when tracing, but we can easily worked around it by Transforming the
NATed IP address and the Ethernet address of the router into the non-NAT address:

Transform denat {
Match (addr=192.168.0.5, ether=01:02:03:04:05:06) Replace (addr=123.45.67.89);
Match (addr=192.168.0.6, ether=01:02:03:04:05:06) Replace (addr=123.45.67.90);
Match (addr=192.168.0.7, ether=01:02:03:04:05:06) Replace (addr=123.45.67.91);
}
Pdu my_pdu Proto my_proto transport tcp/ip/eth {
Extract ether From eth.addr;
Extract addr From ip.addr;
Extract port From tcp.port;
Transform denat;
}

222

About MATE
MATE was originally written by Luis Ontanon, a Telecomunications systems troubleshooter, as a
way to save time filtering out the packets of a single call from huge capture files using just the
calling number. Later he used the time he had saved to make it flexible enough to work with
protocols other than the ones he was directly involved with.

MATE’s configuration tutorial
We’ll show a MATE configuration that first creates Gops for every DNS and HTTP request, then it
ties the Gops together in a Gop based on the host. Finally we’ll separate into different Gogs request
coming from different users.
With this MATE configuration loaded we can:
• use mate.http_use.Duration > 5.5 to filter frames based on the time it takes to load a complete
page from the DNS request to resolve its name until the last image gets loaded.
• use mate.http_use.client == "10.10.10.20" && mate.http_use.host == "www.example.com" to
isolate DNS and HTTP packets related to a visit of a certain user.
• use mate.http_req.Duration > 1.5 to filter all the packets of HTTP requests that take more than
1.5 seconds to complete.
The complete config file is here: web.mate
Note: for this example I used dns.qry.name which is defined since Wireshark version 0.10.9.
Supposing you have a mate plugin already installed you can test it with the current Wireshark
version.

A Gop for DNS requests
First we’ll tell MATE how to create a Gop for each DNS request/response.
MATE needs to know what makes a DNS PDU. We describe it this using a Pdu declaration:

Pdu dns_pdu Proto dns Transport ip {
Extract addr From ip.addr;
Extract dns_id From dns.id;
Extract dns_resp From dns.flags.response;
};
Using Proto dns we tell MATE to create Pdus every time it finds dns. Using Transport ip we inform
MATE that some of the fields we are interested are in the ip part of the frame. Finally, we tell MATE
to import ip.addr as addr, dns.id as dns_id and dns.flags.response as dns_resp.
Once we’ve told MATE how to extract dns_pdus we’ll tell it how to match requests and responses and
223

group them into a Gop. For this we’ll use a Gop declaration to define the Gop, and then, Start and
Stop statements to tell it when the Gop starts and ends.

Gop dns_req On dns_pdu Match (addr,addr,dns_id) {
Start (dns_resp=0);
Stop (dns_resp=1);
};
Using the Gop declaration we tell MATE that the Name of the Gop is dns_req, that dns_pdus can
become members of the Gop, and what is the key used to match the Pdus to the Gop.
The key for this Gop is "addr, addr, dns_id". That means that in order to belong to the same Gop,
dns_pdus have to have both addresses and the request id identical. We then instruct MATE that a
dns_req starts whenever a dns_pdu matches "dns_resp=0" and that it stops when another dns_pdu
matches "dns_resp=1".
At this point, if we open a capture file using this configuration, we are able to use a display filter
mate.dns_req.Time > 1 to see only the packets of DNS requests that take more than one second to
complete.
We can use a display filter mate.dns_req && ! mate.dns_req.Time to find requests for which no
response was given. mate.xxx.Time is set only for Gops that have being stopped.

A Gop for HTTP requests
This other example creates a Gop for every HTTP request.

Pdu http_pdu Proto http Transport tcp/ip {
Extract addr From ip.addr;
Extract port From tcp.port;
Extract http_rq From http.request.method;
Extract http_rs From http.response;
DiscardPduData true;
};
Gop http_req On http_pdu Match (addr, addr, port, port) {
Start (http_rq);
Stop (http_rs);
};
So, if we open a capture using this configuration
• filtering with mate.http_req.Time > 1 will give all the requests where the response header
takes more than one second to come

224

• filtering with mate.http_req.Duration > 1.5 will show those request that take more than 1.5
seconds to complete.
You have to know that mate.xxx.Time gives the time in seconds between the pdu matching the
GopStart and the Pdu matching the GopStop (yes, you can create timers using this!). On the other
hand, mate.xxx.Duration gives you the time passed between the GopStart and the last pdu
assigned to that Gop regardless whether it is a stop or not. After the GopStop, Pdus matching the
Gop’s Key will still be assigned to the same Gop as far as they don’t match the GopStart, in which
case a new Gop with the same key will be created.

Getting DNS and HTTP together into a Gog
We’ll tie together to a single Gog all the http packets belonging to requests and responses to a
certain host and the dns request and response used to resolve its domain name using the Pdu and
Gop definitions of the previous examples
To be able to group DNS and HTTP requests together, we need to import into the Pdus and Gops
some part of information that both those protocols share. Once the Pdus and Gops have been
defined, we can use Extract (for Pdus) and Extract (for Gops) statements to tell MATE what other
protocol fields are to be added to Pdus' and Gops' AVPLs. We add the following statements to the
appropriate declarations:

Extract host From http.host; // to Pdu http_pdu as the last Extract in the list
Extra (host); // to Gop http_req after the Stop
Extract host From dns.qry.name; // to Pdu dns_pdu as the last Extract in the list
Extra (host); // to Gop dns_req after the Stop
Here we’ve told MATE to import http.host into http_pdu and dns.qry.name into dns_pdu as host. We
also have to tell MATE to copy the host attribute from the Pdus to the Gops, we do this using Extra.
Once we’ve got all the data we need in Pdus and Gops, we tell MATE what makes different Gops
belong to a certain Gog.

Gog http_use {
Member http_req (host);
Member dns_req (host);
Expiration 0.75;
};
Using the Gog declaration we tell MATE to define a Gog type Named http_use whose expiration is 0.75
seconds after all the Gops that belong to it had been stopped. After that time, an eventual new Gop
with the same key match will create a new Gog instead of been added to the previous Gog.

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Using the Member statements we tell MATE that http_req*s with the same *host belong to the same
Gog, same thing for *dns_req*s.
So far we have instructed mate to group every packet related to sessions towards a certain host. At
this point if we open a capture file and:
• a display filter mate.http_use.Duration > 5 will show only those requests that have taken more
than 5 seconds to complete starting from the DNS request and ending with the last packet of the
http responses.
• a display filter mate.http_use.host == "www.w3c.org" will show all the packets (both DNS and
HTTP) related to the requests directed to www.w3c.org

Separating requests from multiple users
"Houston: we’ve had a problem here."
This configuration works fine if used for captures taken at the client’s side but deeper in the
network we’d got a real mess. Requests from many users get mixed together into http_uses. Gogs
are created and stopped almost randomly (depending on the timing in which Gops start and stop).
How do we get requests from individual users separated from each other?
MATE has a tool that can be used to resolve this kind of grouping issues. This tool are the
Transforms. Once defined, they can be applied against Pdus, Gops and Gogs and they might replace
or insert more attributes based on what’s there. We’ll use them to create an attribute named client,
using which we’ll separate different requests.
For DNS we need the ip.src of the request moved into the Gop only from the DNS request.
So we first tell MATE to import ip.src as client:

Extract client From ip.src;
Next, we tell MATE to replace ( dns_resp=1, client ) with just dns_resp=1 in the Pdu. That way, we’ll
keep the attribute client only in the DNS request Pdus (i.e. packets coming from the client).To do so,
we have to add a Transform declaration (in this case, with just one clause) before the Pdu
declaration which uses it:

Transform rm_client_from_dns_resp {
Match (dns_resp=1, client) Replace (dns_resp=1);
};
Next, we invoke the transform by adding the following line after the Extract list of the dns_pdu Pdu:

226

Transform rm_client_from_dns_resp;
HTTP is a little trickier. We have to remove the attribute carrying ip.src from both the response and
the "continuations" of the response, but as there is nothing to filter on for the continuations, we
have to add a fake attribute first. And then we have to remove client when the fake attribute
appears. This is possible due to the fact that the Match clauses in the Transform are executed one by
one until one of them succeeds. First, we declare another two Transforms:

Transform rm_client_from_http_resp1 {
Match (http_rq); //first match wins so the request won't get the not_rq attribute
inserted
Match Every (addr) Insert (not_rq); //this line won't be evaluated if the first one
matched so not_rq won't be inserted to requests
};
Transform rm_client_from_http_resp2 {
Match (not_rq, client) Replace (); //replace "client and not_rq" with nothing (will
happen only in the response and eventual parts of it)
};
Next, we add another Extract statement to the http_pdu declaration, and apply both Transforms
declared above in a proper order:

Extract client From ip.src;
Transform rm_client_from_http_resp1, rm_client_from_http_resp2;
In MATE, all the Transform+s listed for an item will be evaluated, while inside a single
+Transform, the evaluation will stop at the first successful Match clause. That’s why we first just
match http_rq to get out of the first sequence before adding the not_rq attribute. Then we apply the
second Transform which removes both not_rq and client if both are there. Yes, +Transform+s are
cumbersome, but they are very useful.
Once we got all what we need in the Pdus, we have to tell MATE to copy the attribute client from the
Pdus to the respective Gops, by adding client to Extra lists of both Gop declarations:

Extra (host, client);
On top of that, we need to modify the old declarations of Gop key to new ones that include both
client and host. So we change the Gog Member declarations the following way:

227

Member http_req (host, client);
Member dns_req (host, client);
Now we got it, every "usage" gets it’s own Gog.

MATE configuration examples
The following is a collection of various configuration examples for MATE. Many of them are useless
because the "conversations" facility does a better job. Anyway they are meant to help users
understanding how to configure MATE.

TCP session
The following example creates a GoP out of every TCP session.

Pdu tcp_pdu
Extract
Extract
Extract
Extract
Extract
};

Proto tcp Transport ip {
addr From ip.addr;
port From tcp.port;
tcp_start From tcp.flags.syn;
tcp_stop From tcp.flags.reset;
tcp_stop From tcp.flags.fin;

Gop tcp_ses On tcp_pdu Match (addr, addr, port, port) {
Start (tcp_start=1);
Stop (tcp_stop=1);
};
Done;
This

probably

would

fine

99.9%

the

cases

but

10.0.0.1:20→10.0.0.2:22

and

10.0.0.1:22→10.0.0.2:20 would both fall into the same gop if they happen to overlap in time.
• filtering with mate.tcp_ses.Time > 1 will give all the sessions that last less than one second
• filtering with mate.tcp_ses.NumOfPdus < 5 will show all tcp sessions that have less than 5
packets.
• filtering with mate.tcp_ses.Id == 3 will show all the packets for the third tcp session MATE has
found

a Gog for a complete FTP session
This configuration allows to tie a complete passive ftp session (including the data transfer) in a
single Gog.

228

Pdu ftp_pdu Proto ftp Transport tcp/ip {
Extract ftp_addr From ip.addr;
Extract ftp_port From tcp.port;
Extract ftp_resp From ftp.response.code;
Extract ftp_req From ftp.request.command;
Extract server_addr From ftp.passive.ip;
Extract server_port From ftp.passive.port;
LastPdu;
};
Pdu ftp_data_pdu Proto ftp-data Transport tcp/ip{
Extract server_addr From ip.src;
Extract server_port From tcp.srcport;
};
Gop ftp_data On ftp_data_pdu (server_addr, server_port) {
Start (server_addr);
};
Gop ftp_ctl On ftp_pdu (ftp_addr, ftp_addr, ftp_port, ftp_port) {
Start (ftp_resp=220);
Stop (ftp_resp=221);
Extra (server_addr, server_port);
};
Gog ftp_ses {
Member ftp_ctl (ftp_addr, ftp_addr, ftp_port, ftp_port);
Member ftp_data (server_addr, server_port);
};
Done;
Note: not having anything to distinguish between ftp-data packets makes this config to create one
Gop for every ftp-data packet instead of each transfer. Pre-started Gops would avoid this.

using RADIUS to filter SMTP traffic of a specific user
Spying on people, in addition to being immoral, is illegal in many countries. This is an example
meant to explain how to do it not an invitation to do so. It’s up to the police to do this kind of job
when there is a good reason to do so.

229

Pdu radius_pdu On radius Transport udp/ip {
Extract addr From ip.addr;
Extract port From udp.port;
Extract radius_id From radius.id;
Extract radius_code From radius.code;
Extract user_ip From radius.framed_addr;
Extract username From radius.username;
}
Gop radius_req On radius_pdu (radius_id, addr, addr, port, port) {
Start (radius_code {1|4|7} );
Stop (radius_code {2|3|5|8|9} );
Extra (user_ip, username);
}
// we define the smtp traffic we want to filter
Pdu user_smtp Proto smtp Transport tcp/ip {
Extract user_ip From ip.addr;
Extract smtp_port From tcp.port;
Extract tcp_start From tcp.flags.syn;
Extract tcp_stop From tcp.flags.reset;
}
Gop user_smtp_ses On user_smtp (user_ip, user_ip, smtp_port!25) {
Start (tcp_start=1);
Stop (tcp_stop=1);
}
// with the following group of groups we'll group toghether the radius and the smtp
// we set a long expiration to avoid the session expire on long pauses.
Gog user_mail {
Expiration 1800;
Member radius_req (user_ip);
Member user_smtp_ses (user_ip);
Extra (username);
}
Done;
Filtering the capture file with mate.user_mail.username == "theuser" will filter the radius
packets and smtp traffic for "theuser".

H323 Calls
This configuration will create a Gog out of every call.

230

Pdu q931 Proto q931 Transport ip {
Extract addr From ip.addr;
Extract call_ref From q931.call_ref;
Extract q931_msg From q931.message_type;
Extract calling From q931.calling_party_number.digits;
Extract called From q931.called_party_number.digits;
Extract guid From h225.guid;
Extract q931_cause From q931.cause_value;
};
Gop q931_leg On q931 Match (addr, addr, call_ref) {
Start (q931_msg=5);
Stop (q931_msg=90);
Extra (calling, called, guid, q931_cuase);
};
Pdu ras Proto h225.RasMessage Transport ip {
Extract addr From ip.addr;
Extract ras_sn From h225.requestSeqNum;
Extract ras_msg From h225.RasMessage;
Extract guid From h225.guid;
};
Gop ras_req On ras Match (addr, addr, ras_sn) {
Start (ras_msg {0|3|6|9|12|15|18|21|26|30} );
Stop (ras_msg {1|2|4|5|7|8|10|11|13|14|16|17|19|20|22|24|27|28|29|31});
Extra (guid);
};
Gog call {
Member ras_req (guid);
Member q931_leg (guid);
Extra (called,calling,q931_cause);
};
Done;
with this we can:
• filter all signalling for a specific caller: mate.call.caller == "123456789"
• filter all signalling for calls with a specific release cause: mate.call.q931_cause == 31
• filter all signalling for very short calls: mate.q931_leg.Time < 5

231

MMS
With this example, all the components of an MMS send or receive will be tied into a single Gog.
Note that this example uses the Payload clause because MMS delivery uses MMSE over either HTTP
or WSP. As it is not possible to relate the retrieve request to a response by the means of MMSE only
(the request is just an HTTP GET without any MMSE), a Gop is made of HTTP Pdus but MMSE data
need to be extracted from the bodies.

## WARNING: this example has been blindly translated from the "old" MATE syntax
## and it has been verified that Wireshark accepts it. However, it has not been
## tested against any capture file due to lack of the latter.
Transform rm_client_from_http_resp1 {
Match (http_rq);
Match Every (addr) Insert (not_rq);
};
Transform rm_client_from_http_resp2 {
Match (not_rq,ue) Replace ();
};
Pdu mmse_over_http_pdu Proto http Transport tcp/ip {
Payload mmse;
Extract addr From ip.addr;
Extract port From tcp.port;
Extract http_rq From http.request;
Extract content From http.content_type;
Extract resp From http.response.code;
Extract method From http.request.method;
Extract host From http.host;
Extract content From http.content_type;
Extract trx From mmse.transaction_id;
Extract msg_type From mmse.message_type;
Extract notify_status From mmse.status;
Extract send_status From mmse.response_status;
Transform rm_client_from_http_resp1, rm_client_from_http_resp2;
};
Gop mmse_over_http On mmse_over_http_pdu Match (addr, addr, port, port) {
Start (http_rq);
Stop (http_rs);
Extra (host, ue, resp, notify_status, send_status, trx);
};
Transform mms_start {
Match Loose() Insert (mms_start);
};

232

Pdu mmse_over_wsp_pdu Proto wsp Transport ip {
Payload mmse;
Extract trx From mmse.transaction_id;
Extract msg_type From mmse.message_type;
Extract notify_status From mmse.status;
Extract send_status From mmse.response_status;
Transform mms_start;
};
Gop mmse_over_wsp On mmse_over_wsp_pdu Match (trx) {
Start (mms_start);
Stop (never);
Extra (ue, notify_status, send_status);
};
Gog mms {
Member mmse_over_http (trx);
Member mmse_over_wsp (trx);
Extra (ue, notify_status, send_status, resp, host, trx);
Expiration 60.0;
};

MATE’s configuration library
The MATE library (will) contains GoP definitions for several protocols. Library protocols are
included in your MATE config using: Action=Include; Lib=proto_name;.
For Every protocol with a library entry, we’ll find defined what from the PDU is needed to create a
GoP for that protocol, eventually any criteria and the very essential GoP definition (i.e. GopDef,
GopStart and GopStop).
It seems that this code is written in the old syntax of MATE. So far it has not been
NOTE

transcribed into the new format. It may still form the basis to recreate these in the
new format.

General use protocols
TCP
It will create a GoP for every TCP session, If it is used it should be the last one in the list. And every
other proto on top of TCP should be declared with Stop=TRUE; so the a TCP PDU is not created where
we got already one going on.

233

Action=PduDef; Name=tcp_pdu; Proto=tcp; Transport=ip; addr=ip.addr; port=tcp.port;
tcp_start=tcp.flags.syn; tcp_stop=tcp.flags.fin; tcp_stop=tcp.flags.reset;
Action=GopDef; Name=tcp_session; On=tcp_pdu; addr; addr; port; port;
Action=GopStart; For=tcp_session; tcp_start=1;
Action=GopStop; For=tcp_session; tcp_stop=1;

DNS
will create a GoP containing every request and it’s response (eventually retransmissions too).

Action=PduDef; Name=dns_pdu; Proto=dns; Transport=udp/ip; addr=ip.addr; port=udp.port;
dns_id=dns.id; dns_rsp=dns.flags.response;
Action=GopDef; Name=dns_req; On=dns_pdu; addr; addr; port!53; dns_id;
Action=GopStart; For=dns_req; dns_rsp=0;
Action=GopStop; For=dns_req; dns_rsp=1;

RADIUS
A Gop for every transaction.

Action=PduDef; Name=radius_pdu; Proto=radius; Transport=udp/ip; addr=ip.addr;
port=udp.port; radius_id=radius.id; radius_code=radius.code;
Action=GopDef; Name=radius_req; On=radius_pdu; radius_id; addr; addr; port; port;
Action=GopStart; For=radius_req; radius_code|1|4|7;
Action=GopStop; For=radius_req; radius_code|2|3|5|8|9;

RTSP

Action=PduDef; Name=rtsp_pdu; Proto=rtsp; Transport=tcp/ip; addr=ip.addr;
port=tcp.port; rtsp_method=rtsp.method;
Action=PduExtra; For=rtsp_pdu; rtsp_ses=rtsp.session; rtsp_url=rtsp.url;
Action=GopDef; Name=rtsp_ses; On=rtsp_pdu; addr; addr; port; port;
Action=GopStart; For=rtsp_ses; rtsp_method=DESCRIBE;
Action=GopStop; For=rtsp_ses; rtsp_method=TEARDOWN;
Action=GopExtra; For=rtsp_ses; rtsp_ses; rtsp_url;

VoIP/Telephony
Most protocol definitions here will create one Gop for every Call Leg unless stated.

234

ISUP

Action=PduDef; Name=isup_pdu; Proto=isup; Transport=mtp3; mtp3pc=mtp3.dpc;
mtp3pc=mtp3.opc; cic=isup.cic; isup_msg=isup.message_type;
Action=GopDef; Name=isup_leg; On=isup_pdu; ShowPduTree=TRUE; mtp3pc; mtp3pc; cic;
Action=GopStart; For=isup_leg; isup_msg=1;
Action=GopStop; For=isup_leg; isup_msg=16;

Q931

Action=PduDef; Name=q931_pdu; Proto=q931; Stop=TRUE; Transport=tcp/ip; addr=ip.addr;
call_ref=q931.call_ref; q931_msg=q931.message_type;
Action=GopDef; Name=q931_leg; On=q931_pdu; addr; addr; call_ref;
Action=GopStart; For=q931_leg; q931_msg=5;
Action=GopStop; For=q931_leg; q931_msg=90;

H225 RAS

Action=PduDef; Name=ras_pdu; Proto=h225.RasMessage; Transport=udp/ip; addr=ip.addr;
ras_sn=h225.RequestSeqNum; ras_msg=h225.RasMessage;
Action=PduExtra; For=ras_pdu; guid=h225.guid;
Action=GopDef; Name=ras_leg; On=ras_pdu; addr; addr; ras_sn;
Action=GopStart; For=ras_leg; ras_msg|0|3|6|9|12|15|18|21|26|30;
Action=GopStop; For=ras_leg;
ras_msg|1|2|4|5|7|8|10|11|13|14|16|17|19|20|22|24|27|28|29|31;
Action=GopExtra; For=ras_leg; guid;

SIP

Action=PduDef; Proto=sip_pdu; Transport=tcp/ip; addr=ip.addr; port=tcp.port;
sip_method=sip.Method; sip_callid=sip.Call-ID; calling=sdp.owner.username;
Action=GopDef; Name=sip_leg; On=sip_pdu; addr; addr; port; port;
Action=GopStart; For=sip; sip_method=INVITE;
Action=GopStop; For=sip; sip_method=BYE;

MEGACO
Will create a Gop out of every transaction.

235

To "tie" them to your call’s GoG use: Action=GogKey; Name=your_call; On=mgc_tr; addr!mgc_addr;
megaco_ctx;

Action=PduDef; Name=mgc_pdu; Proto=megaco; Transport=ip; addr=ip.addr;
megaco_ctx=megaco.context; megaco_trx=megaco.transid; megaco_msg=megaco.transaction;
term=megaco.termid;
Action=GopDef; Name=mgc_tr; On=mgc_pdu; addr; addr; megaco_trx;
Action=GopStart; For=mgc_tr; megaco_msg|Request|Notify;
Action=GopStop; For=mgc_tr; megaco_msg=Reply;
Action=GopExtra; For=mgc_tr; term^DS1; megaco_ctx!Choose one;

MATE’s reference manual
Attribute Value Pairs
MATE uses AVPs for almost everything: to keep the data it has extracted from the frames' trees as
well as to keep the elements of the configuration.
These "pairs" (actually tuples) are made of a name, a value and, in case of configuration AVPs, an
operator. Names and values are strings. AVPs with operators other than = are used only in the
configuration and are used for matching AVPs of Pdus, GoPs and GoGs in the analysis phase.
Name
The name is a string used to refer to a class of AVPs. Two attributes won’t match unless their names
are identical. Capitalized names are reserved for keywords (you can use them for your elements if
you want but I think it’s not the case). MATE attribute names can be used in Wireshark’s display
filters the same way like names of protocol fields provided by dissectors, but they are not just
references to (or aliases of) protocol fields.
Value
The value is a string. It is either set in the configuration (for configuration AVPs) or by MATE while
extracting interesting fields from a dissection tree and/or manipulating them later. The values
extracted from fields use the same representation as they do in filter strings.
Operators
Currently only match operators are defined (there are plans to (re)add transform attributes but
some internal issues have to be solved before that). The match operations are always performed
between two operands: the value of an AVP stated in the configuration and the value of an AVP (or
several AVPs with the same name) extracted from packet data (called "data AVPs"). It is not possible
to match data AVPs to each other.

236

The defined match operators are:
• Equal = test for equality, that is: either the value strings are identical or the match will fail.
• Not Equal ! will match only if the value strings aren’t equal.
• One Of {} will match if one of the value strings listed is equal to the data AVP’s string. Individual
tems of the list inside the curly braces are separated using | character.
• Starts With ^ will match if the configuration value string matches the first characters of the data
AVP’s value string.
• Ends With $ will match if the configuration value string matches the last characters of the data
AVP’s value string.
• Contains ~ will match if the configuration value string matches a substring of the characters of
the data AVP’s value string.
• Lower Than < will match if the data AVP’s value string is semantically lower than the
configuration value string.
• Higher Than > will match if the data AVP’s value string is semantically higher than the
configuration value string.
• Exists ? (can be omitted) will match if the AVP name matches, regardless what the value string
is.
Equal AVP Operator

This operator tests whether the values of the operator and the operand AVP are equal.
Example
attrib=aaa matches attrib=aaa
attrib=aaa does not match attrib=bbb
Not equal AVP operator

This operator matches if the value strings of two AVPs are not equal.
Example
attrib=aaa matches attrib!bbb
attrib=aaa does not match attrib!aaa
"One of" AVP operator

The "one of" operator matches if the data AVP value is equal to one of the values listed in the "one
of" AVP.
Example
attrib=1 matches attrib{1|2|3}
attrib=2 matches attrib{1|2|3}

237

attrib=4 does not match attrib{1|2|3}
"Starts with" AVP operator

The "starts with" operator matches if the first characters of the data AVP value are identical to the
configuration AVP value.
Example
attrib=abcd matches attrib^abc
attrib=abc matches attrib^abc
attrib=ab does not match attrib^abc
attrib=abcd does not match attrib^bcd
attrib=abc does not match attrib^abcd
"Ends with" operator

The ends with operator will match if the last bytes of the data AVP value are equal to the
configuration AVP value.
Example
attrib=wxyz matches attrib$xyz
attrib=yz does not match attrib$xyz
attrib=abc…wxyz does not match attrib$abc
Contains operator

The "contains" operator will match if the data AVP value contains a string identical to the
configuration AVP value.
Example
attrib=abcde matches attrib~bcd
attrib=abcde matches attrib~abc
attrib=abcde matches attrib~cde
attrib=abcde does not match attrib~xyz
"Lower than" operator

The "lower than" operator will match if the data AVP value is semantically lower than the
configuration AVP value.
Example
attrib=abc matches attribabc
attrib=3 matches attrib>2
but beware: attrib=9 does not match attrib>10
attrib=abc does not match attrib>bcd
attrib=abc does not match attrib>abc
BUGS
It should check whether the values are numbers and compare them numerically
Exists operator

The exists operator will always match as far as the two operands have the same name.
Examples
attrib=abc matches attrib?
attrib=abc matches attrib (this is just an alternative notation of the previous example)
obviously attrib=abc does not match other_attrib?

Attribute/Value Pair List (AVPL)
Pdus, GoPs and GoGs use an AVPL to contain the tracing information. An AVPL is an unsorted set of
AVPs that can be matched against other AVPLs.
Operations between AVPLs
There are three types of match operations that can be performed between AVPLs. The
Pdu’s/GoP’s/GoG’s AVPL will be always one of the operands; the AVPL operator (match type) and the
second operand AVPL will always come from the configuration. Note that a diverse AVP match
operator may be specified for each AVP in the configuration AVPL.
An AVPL match operation returns a result AVPL. In Transforms, the result AVPL may be replaced by
another AVPL. The replacement means that the existing data AVPs are dropped and the
replacement AVPL from the configuration is Merged to the data AVPL of the Pdu/GoP/GoG.
• Loose Match: Will match if at least one of the AVPs of the two operand AVPLs match. If it

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matches, it returns a result AVPL containing all AVPs from the data AVPL that did match the
configuration’s AVPs.
• "Every" Match: Will match if none of the AVPs of the configuration AVPL fails to match an AVP
in the data AVPL, even if not all of the configuration AVPs have a match. If it matches, it returns
a result AVPL containing all AVPs from the data AVPL that did match an AVP in the
configuration AVPL.
• Strict Match: Will match if and only if each of the AVPs in the configuration AVPL has at least
one match in the data AVPL. If it matches, it returns a result AVPL containing those AVPs from
the data AVPL that matched.
Loose Match

A loose match between AVPLs succeeds if at least one of the data AVPs matches at least one of the
configuration AVPs. Its result AVPL contains all the data AVPs that matched.
Loose matches are used in Extra operations against the Pdu's AVPL to merge the result into Gop's
AVPL, and against Gop's AVPL to merge the result into Gog's AVPL. They may also be used in Criteria
and Transforms.
NOTE

As of current (2.0.1), Loose Match does not work as described here, see Bug 12184.
Only use in Transforms and Criteria is effectively affected by the bug.

Loose Match Examples
(attr_a=aaa, attr_b=bbb, attr_c=xxx) Match Loose (attr_a?, attr_c?) =⇒ (attr_a=aaa, attr_c=xxx)
(attr_a=aaa, attr_b=bbb, attr_c=xxx) Match Loose (attr_a?, attr_c=ccc) =⇒ (attr_a=aaa)
(attr_a=aaa, attr_b=bbb, attr_c=xxx) Match Loose (attr_a=xxx; attr_c=ccc) =⇒ No Match!
Every Match

An "every" match between AVPLs succeeds if none of the configuration’s AVPs that have a
counterpart in the data AVPL fails to match. Its result AVPL contains all the data AVPs that matched.
These may only be used in Criteria and Transforms.
NOTE

As of current (2.0.1), Loose Match does not work as described here, see Bug 12184.

"Every" Match Examples
(attr_a=aaa, attr_b=bbb, attr_c=xxx) Match Every (attr_a?, attr_c?) =⇒ (attr_a=aaa, attr_c=xxx)
(attr_a=aaa, attr_b=bbb, attr_c=xxx) Match Every (attr_a?, attr_c?, attr_d=ddd) =⇒ (attr_a=aaa,
attr_c=xxx)
(attr_a=aaa, attr_b=bbb, attr_c=xxx) Match Every (attr_a?, attr_c=ccc) =⇒ No Match!
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(attr_a=aaa; attr_b=bbb; attr_c=xxx) Match Every (attr_a=xxx, attr_c=ccc) =⇒ No Match!
Strict Match

A Strict match between AVPLs succeeds if and only if every AVP in the configuration AVPL has at
least one counterpart in the data AVPL and none of the AVP matches fails. The result AVPL contains
all the data AVPs that matched.
These are used between Gop keys (key AVPLs) and Pdu AVPLs. They may also be used in Criteria
and Transforms.
Examples
(attr_a=aaa, attr_b=bbb, attr_c=xxx) Match Strict (attr_a?, attr_c=xxx) =⇒ (attr_a=aaa, attr_c=xxx)
(attr_a=aaa, attr_b=bbb, attr_c=xxx, attr_c=yyy) Match Strict (attr_a?, attr_c?) =⇒ (attr_a=aaa,
attr_c=xxx, attr_c=yyy)
(attr_a=aaa, attr_b=bbb, attr_c=xxx) Match Strict (attr_a?, attr_c=ccc) =⇒ No Match!
(attr_a=aaa, attr_b=bbb, attr_c=xxx) Match Strict (attr_a?, attr_c?, attr_d?) =⇒ No Match!
AVPL Merge

An AVPL may be merged into another one. That would add to the latter every AVP from the former
that does not already exist there.
This operation is done
• between the result of a key match and the Gop’s or Gog’s AVPL,
• between the result of an Extra match and the Gop’s or Gog’s AVPL,
• between the result of a Transform match and Pdu’s/Gop’s AVPL. If the operation specified by the
Match clause is Replace, the result AVPL of the match is removed from the item’s AVPL before
the modify_avpl is merged into it.
Examples
(attr_a=aaa, attr_b=bbb) Merge (attr_a=aaa, attr_c=xxx) former becomes (attr_a=aaa, attr_b=bbb,
attr_c=xxx)
(attr_a=aaa, attr_b=bbb) Merge (attr_a=aaa, attr_a=xxx) former becomes (attr_a=aaa, attr_a=xxx,
attr_b=bbb)
(attr_a=aaa, attr_b=bbb) Merge (attr_c=xxx, attr_d=ddd) former becomes (attr_a=aaa, attr_b=bbb,
attr_c=xxx, attr_d=ddd)

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Transforms

A Transform is a sequence of Match rules optionally followed by an instruction how to modify the
match result using an additional AVPL. Such modification may be an Insert (merge) or a Replace.
The syntax is as follows:

Transform name {
Match [Strict|Every|Loose] match_avpl [[Insert|Replace] modify_avpl] ; // may
occur multiple times, at least once
};
For examples of Transforms, check the Manual page.
TODO: migrate the examples here?
The list of Match rules inside a Transform is processed top to bottom; the processing ends as soon
as either a Match rule succeeds or all have been tried in vain.
Transforms can be used as helpers to manipulate an item’s AVPL before the item is processed
further. An item declaration may contain a Transform clause indicating a list of previously declared
Transforms. Regardless whether the individual transforms succeed or fail, the list is always
executed completely and in the order given, i.e. left to right.
In MATE configuration file, a Transform must be declared before declaring any item which uses it.

Configuration AVPLs
Pdsu’s configuration actions
The following configuration AVPLs deal with PDU creation and data extraction.
Pdu declaration block header
In each frame of the capture, MATE will look for source proto_name's PDUs in the order in which the
declarations appear in its configuration and will create Pdus of every type it can from that frame,
unless specifically instructed that some Pdu type is the last one to be looked for in the frame. If told
so for a given type, MATE will extract all Pdus of that type and the previously declared types it finds
in the frame but not those declared later.
The complete declaration of a Pdu looks as below; the mandatory order of the diverse clauses is as
shown.

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Pdu name Proto proto_name Transport proto1[/proto2/proto3[/...]]] {
Payload proto; //optional, no default value
Extract attribute From proto.field ; //may occur multiple times, at least once
Transform (transform1[, transform2[, ...]]); //optional
Criteria [{Accept|Reject}] [{Strict|Every|Loose} match_avpl];
DropUnassigned {true|false}; //optional, default=false
DiscardPduData {true|false}; //optional, default=false
LastExtracted {true|false}; //optional, default=false
};

Pdu name
The name is a mandatory attribute of a Pdu declaration. It is chosen arbitrarily, except that each name
may only be used once in MATE’s configuration, regardless the class of an item it is used for. The
name is used to distinguish between different types of Pdus, Gops, and Gogs. The name is also used as
part of the filterable fields' names related to this type of Pdu which MATE creates.
However, several Pdu declarations may share the same name. In such case, all of them are created
from each source PDU matching their Proto, Transport, and Payload clauses, while the bodies of
their declarations may be totally different from each other. Together with the Accept (or Reject)
clauses, this feature is useful when it is necessary to build the Pdu’s AVPL from different sets of
source fields depending on contents (or mere presence) of other source fields.
Proto and Transport clauses

Every instance of the protocol proto_name PDU in a frame will generate one Pdu with the AVPs
extracted from fields that are in the proto_name's range and/or the ranges of underlying protocols
specified by the Transport list. It is a mandatory attribute of a Pdu declaration. The proto_name is the
name of the protocol as used in Wireshark display filter.
The Pdu’s Proto, and its Transport list of protocols separated by / tell MATE which fields of a frame
can get into the Pdu’s AVPL. In order that MATE would extract an attribute from a frame’s protocol
tree, the area representing the field in the hex display of the frame must be within the area of
either the Proto or it’s relative Transport s. Transport s are chosen moving backwards from the
protocol area, in the order they are given.
Proto http Transport tcp/ip does what you’d expect it to - it selects the nearest tcp range that
precedes the current http range, and the nearest ip range that precedes that tcp range. If there is
another ip range before the nearest one (e.g. in case of IP tunneling), that one is not going to be
selected. Transport tcp/ip/ip that "logically" should select the encapsulating IP header too doesn’t
work so far.
Once we’ve selected the Proto and Transport ranges, MATE will fetch those protocol fields belonging
to them whose extraction is declared using the Extract clauses for the Pdu type. The Transport list is
also mandatory, if you actually don’t want to use any transport protocol, use Transport mate. (This

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didn’t work until 0.10.9).
Payload clause

Other than the Pdu’s Proto and its Transport protocols, there is also a Payload attribute to tell MATE
from which ranges of Proto's payload to extract fields of a frame into the Pdu. In order to extract an
attribute from a frame’s tree the highlighted area of the field in the hex display must be within the
area of the Proto's relative payload(s). Payload s are choosen moving forward from the protocol
area, in the order they are given. Proto http Transport tcp/ip Payload mmse will select the first
mmse range after the current http range. Once we’ve selected the Payload ranges, MATE will fetch
those protocol fields belonging to them whose extraction is declared using the Extract clauses for
the Pdu type.
Extract clause

Each Extract clause tells MATE which protocol field value to extract as an AVP value and what
string to use as the AVP name. The protocol fields are referred to using the names used in
Wireshark display filters. If there is more than one such protocol field in the frame, each instance
that fulfills the criteria stated above is extracted into its own AVP. The AVP names may be chosen
arbitrarily, but to be able to match values originally coming from different Pdus (e.g., hostname
from DNS query and a hostname from HTTP GET request) later in the analysis, identical AVP names
must be assigned to them and the dissectors must provide the field values in identical format
(which is not always the case).
Transform clause

The Transform clause specifies a list of previously declared Transform s to be performed on the Pdu’s
AVPL after all protocol fields have been extracted to it. The list is always executed completely, left to
right. On the contrary, the list of Match clauses inside each individual Transform is executed only
until the first match succeeds.
Criteria clause

This clause tells MATE whether to use the Pdu for analysis. It specifies a match AVPL, an AVPL
match type (Strict, Every, or Loose) and the action to be performed (Accept or Reject) if the match
succeeds. Once every attribute has been extracted and eventual transform list has been executed,
and if the Criteria clause is present, the Pdu’s AVPL is matched against the match AVPL; if the
match succeeds, the action specified is executed, i.e. the Pdu is accepted or rejected. The default
behaviours used if the respective keywords are omitted are Strict and Accept. Accordingly, if the
clause is omitted, all Pdus are accepted.
DropUnassigned clause

If set to TRUE, MATE will destroy the Pdu if it cannot assign it to a Gop. If set to FALSE (the default if
not given), MATE will keep them.

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DiscardPduData clause

If set to TRUE, MATE will delete the Pdu’s AVPL once it has analyzed it and eventually extracted some
AVPs from it into the Gop’s AVPL. This is useful to save memory (of which MATE uses a lot). If set to
FALSE (the default if not given), MATE will keep the Pdu attributes.
LastExtracted clause

If set to FALSE (the default if not given), MATE will continue to look for Pdus of other types in the
frame. If set to TRUE, it will not try to create Pdus of other types from the current frame, yet it will
continue to try for the current type.
Gop’s configuration actions
Gop declaration block header

Declares a Gop type and its prematch candidate key.

Gop name On pduname Match key {
Start match_avpl; // optional
Stop match_avpl; // optional
Extra match_avpl; // optional
Transform transform_list; // optional
Expiration time; // optional
IdleTimeout time; // optional
Lifetime time; // optional
DropUnassigned [TRUE|FALSE]; //optional
ShowTree [NoTree|PduTree|FrameTree|BasicTree]; //optional
ShowTimes [TRUE|FALSE]; //optional, default TRUE
};

Gop name

The name is a mandatory attribute of a Gop declaration. It is chosen arbitrarily, except that each name
may only be used once in MATE’s configuration, regardless the class of an item it is used for. The
name is used to distinguish between different types of Pdus, Gops, and Gogs. The name is also used as
part of the filterable fields' names related to this type of Gop which MATE creates.
On clause

The name of Pdus which this type of Gop is supposed to be groupping. It is mandatory.
Match clause

Defines what AVPs form up the key part of the Gop’s AVPL (the Gop’s key AVPL or simply the Gop’s
key). All Pdus matching the key AVPL of an active Gop are assigned to that Gop; a Pdu which
contains the AVPs whose attribute names are listed in the Gop’s key AVPL, but they do not strictly

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match any active Gop’s key AVPL, will create a new Gop (unless a Start clause is given). When a Gop
is created, the elements of its key AVPL are copied from the creating Pdu.
Start clause

If given, it tells MATE what match_avpl must a Pdu’s AVPL match, in addition to matching the Gop’s
key, in order to start a Gop. If not given, any Pdu whose AVPL matches the Gop’s Key AVPL will act as
a start for a Gop. The Pdu’s AVPs matching the match_avpl are not automatically copied into the
Gop’s AVPL.
Stop clause

If given, it tells MATE what match_avpl must a Pdu’s AVPL match, in addition to matching the Gop’s
key, in order to stop a Gop. If omitted, the Gop is "auto-stopped" - that is, the Gop is marked as
stopped as soon as it is created. The Pdu’s AVPs matching the match_avpl are not automatically
copied into the Gop’s AVPL.
Extra clause

If given, tells MATE which AVPs from the Pdu’s AVPL are to be copied into the Gop’s AVPL in
addition to the Gop’s key.
Transform clause

The Transform clause specifies a list of previously declared Transform s to be performed on the Gop’s
AVPL after the AVPs from each new Pdu, specified by the key AVPL and the Extra clause’s
match_avpl, have been merged into it. The list is always executed completely, left to right. On the
contrary, the list of Match clauses inside each individual Transform is executed only until the first
match succeeds.
Expiration clause

A (floating) number of seconds after a Gop is Stop ped during which further Pdus matching the Stop
ped Gop’s key but not the Start condition will still be assigned to that Gop. The default value of zero
has an actual meaning of infinity, as it disables this timer, so all Pdus matching the Stop ped Gop’s
key will be assigned to that Gop unless they match the Start condition.
IdleTimeout clause

A (floating) number of seconds elapsed from the last Pdu assigned to the Gop after which the Gop
will be considered released. The default value of zero has an actual meaning of infinity, as it
disables this timer, so the Gop won’t be released even if no Pdus arrive - unless the Lifetime timer
expires.
Lifetime clause

A (floating) of seconds after the Gop Start after which the Gop will be considered released
regardless anything else. The default value of zero has an actual meaning of infinity.

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DropUnassigned clause

Whether or not a Gop that has not being assigned to any Gog should be discarded. If TRUE, the Gop is
discarded right after creation. If FALSE, the default, the unassigned Gop is kept. Setting it to TRUE
helps save memory and speed up filtering.
TreeMode clause

Controls the display of Pdus subtree of the Gop:
• NoTree: completely suppresses showing the tree
• PduTree: the tree is shown and shows the Pdus by Pdu Id
• FrameTree: the tree is shown and shows the Pdus by the frame number in which they are
• BasicTree: needs investigation
ShowTimes clause

Whether or not to show the times subtree of the Gop. If TRUE, the default, the subtree with the
timers is added to the Gop’s tree. If FALSE, the subtree is suppressed.
Gog’s configuration actions
Gop declaration block header

Declares a Gog type and its prematch candidate key.

Gog name {
Member gopname (key); // mandatory, at least one
Extra match_avpl; // optional
Transform transform_list; // optional
Expiration time; // optional, default 2.0
GopTree [NoTree|PduTree|FrameTree|BasicTree]; // optional
ShowTimes [TRUE|FALSE]; // optional, default TRUE
};

Gop name

The name is a mandatory attribute of a Gog declaration. It is chosen arbitrarily, except that each name
may only be used once in MATE’s configuration, regardless the class of an item it is used for. The
name is used to distinguish between different types of Pdus, Gops, and Gogs. The name is also used as
part of the filterable fields' names related to this type of Gop which MATE creates.
Member clause

Defines the key AVPL for the Gog individually for each Gop type gopname. All gopname type Gops
whose key AVPL matches the corresponding key AVPL of an active Gog are assigned to that Gog; a

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Gop which contains the AVPs whose attribute names are listed in the Gog’s corresponding key AVPL,
but they do not strictly match any active Gog’s key AVPL, will create a new Gog. When a Gog is
created, the elements of its key AVPL are copied from the creating Gop.
Although the key AVPLs are specified separately for each of the Member gopname s, in most cases
they are identical, as the very purpose of a Gog is to group together Gops made of Pdus of different
types.
Extra clause

If given, tells MATE which AVPs from any of the Gop’s AVPL are to be copied into the Gog’s AVPL in
addition to the Gog’s key.
Expiration clause

A (floating) number of seconds after all the Gops assigned to a Gog have been released during
which new Gops matching any of the session keys should still be assigned to the existing Gog
instead of creating a new one. Its value can range from 0.0 to infinite. Defaults to 2.0 seconds.
Transform clause

The Transform clause specifies a list of previously declared Transform s to be performed on the Gog’s
AVPL after the AVPs from each new Gop, specified by the key AVPL and the Extra clause’s
match_avpl, have been merged into it. The list is always executed completely, left to right. On the
contrary, the list of Match clauses inside each individual Transform is executed only until the first
match succeeds.
TreeMode clause

Controls the display of Gops subtree of the Gog:
• NoTree: completely suppresses showing the tree
• BasicTree: needs investigation
• FullTree: needs investigation
ShowTimes clause

Whether or not to show the times subtree of the Gog. If TRUE, the default, the subtree with the timers
is added to the Gog’s tree. If FALSE, the subtree is suppressed.
Settings Config AVPL
The Settings config element is used to pass to MATE various operational parameters. the possible
parameters are

248

GogExpiration

How long in seconds after all the gops assigned to a gog have been released new gops matching any
of the session keys should create a new gog instead of being assigned to the previous one. Its value
can range from 0.0 to infinite. Defaults to 2.0 seconds.
DiscardPduData

Whether or not the AVPL of every Pdu should be deleted after it was being processed (saves
memory). It can be either TRUE or FALSE. Defaults to TRUE. Setting it to FALSE can save you from a
headache if your config does not work.
DiscardUnassignedPdu

Whether Pdus should be deleted if they are not assigned to any Gop. It can be either TRUE or FALSE.
Defaults to FALSE. Set it to TRUE to save memory if unassigned Pdus are useless.
DiscardUnassignedGop

Whether GoPs should be deleted if they are not assigned to any session. It can be either TRUE or
FALSE. Defaults to FALSE. Setting it to TRUE saves memory.
ShowPduTree
ShowGopTimes

Debugging Stuff
The following settings are used to debug MATE and its configuration. All levels are integers ranging
from 0 (print only errors) to 9 (flood me with junk), defaulting to 0.
Debug declaration block header

Debug {
Filename "path/name"; //optional, no default value
Level [0-9]; //optional, generic debug level
Pdu Level [0-9]; //optional, specific debug level for Pdu handling
Gop Level [0-9]; //optional, specific debug level for Gop handling
Gog Level [0-9]; //optional, specific debug level for Gog handling
};

Filename clause

The {{{path/name}}} is a full path to the file to which debug output is to be written. Non-existent file
will be created, existing file will be overwritten at each opening of a capture file. If the statement is
missing, debug messages are written to console, which means they are invisible on Windows.

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Level clause

Sets the level of debugging for generic debug messages. It is an integer ranging from 0 (print only
errors) to 9 (flood me with junk).
Pdu Level clause

Sets the level of debugging for messages regarding Pdu creation. It is an integer ranging from 0
(print only errors) to 9 (flood me with junk).
Gop Level clause

Sets the level of debugging for messages regarding Pdu analysis (that is how do they fit into ?GoPs).
It is an integer ranging from 0 (print only errors) to 9 (flood me with junk).
Gog Level clause

Sets the level of debugging for messages regarding GoP analysis (that is how do they fit into ?GoGs).
It is an integer ranging from 0 (print only errors) to 9 (flood me with junk).
Settings Example

Action=Settings; SessionExpiration=3.5; DiscardPduData=FALSE;

Action=Include
Will include a file to the configuration.

Action=Include; {Filename=filename;|Lib=libname;}

Filename

The filename of the file to include. If it does not beging with / it will look for the file in the current
path.
Lib

The name of the lib config to include. will look for libname.mate in wiresharks_dir/matelib.
Include Example

Action=Include; Filename=rtsp.mate;
This will include the file called "rtsp.mate" into the current config.

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Appendix A: Wireshark Messages
Wireshark provides you with additional information generated out of the plain packet data or it
may need to indicate dissection problems. Messages generated by Wireshark are usually placed in
square brackets (“[]”).

Packet List Messages
These messages might appear in the packet list.

[Malformed Packet]
Malformed packet means that the protocol dissector can’t dissect the contents of the packet any
further. There can be various reasons:
• Wrong dissector: Wireshark erroneously has chosen the wrong protocol dissector for this
packet. This will happen e.g. if you are using a protocol not on its well known TCP or UDP port.
You may try Analyze|Decode As to circumvent this problem.
• Packet not reassembled: The packet is longer than a single frame and it is not reassembled, see
Packet Reassembly for further details.
• Packet is malformed: The packet is actually wrong (malformed), meaning that a part of the
packet is just not as expected (not following the protocol specifications).
• Dissector is buggy: The corresponding protocol dissector is simply buggy or still incomplete.
Any of the above is possible. You’ll have to look into the specific situation to determine the reason.
You could disable the dissector by disabling the protocol on the Analyze menu and check how
Wireshark displays the packet then. You could (if it’s TCP) enable reassembly for TCP and the
specific dissector (if possible) in the Edit|Preferences menu. You could check the packet contents
yourself by reading the packet bytes and comparing it to the protocol specification. This could
reveal a dissector bug. Or you could find out that the packet is indeed wrong.

[Packet size limited during capture]
The packet size was limited during capture, see “Limit each packet to n bytes” at the The “Capture
Options” dialog box. While dissecting, the current protocol dissector was simply running out of
packet bytes and had to give up. There’s nothing else you can do now, except to repeat the whole
capture process again with a higher (or no) packet size limitation.

Packet Details Messages
These messages might appear in the packet details.

251

[Response in frame: 123]
The current packet is the request of a detected request/response pair. You can directly jump to the
corresponding response packet just by double clicking on this message.

[Request in frame: 123]
Same as “Response in frame: 123” above, but the other way round.

[Time from request: 0.123 seconds]
The time between the request and the response packets.

[Stream setup by PROTOCOL (frame 123)]
The session control protocol (SDP, H225, etc) message which signaled the creation of this session.
You can directly jump to the corresponding packet just by double clicking on this message.

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Appendix B: Files and Folders
Capture Files
To understand which information will remain available after the captured packets are saved to a
capture file, it’s helpful to know a bit about the capture file contents.
Wireshark uses the pcapng file format as the default format to save captured packets. It is very
flexible but other tools may not support it.
Wireshark also supports the libpcap file format. This is a much simpler format and is well
established. However, it has some drawbacks: it’s not extensible and lacks some information that
would be really helpful (e.g. being able to add a comment to a packet such as “the problems start
here” would be really nice).
In addition to the libpcap format, Wireshark supports several different capture file formats.
However, the problems described above also applies for these formats.

Libpcap File Contents
At the start of each libpcap capture file some basic information is stored like a magic number to
identify the libpcap file format. The most interesting information of this file start is the link layer
type (Ethernet, 802.11, MPLS, etc).
The following data is saved for each packet:
• The timestamp with millisecond resolution
• The packet length as it was “on the wire”
• The packet length as it’s saved in the file
• The packet’s raw bytes
A

detailed

description

the

libpcap

file

format

can

found

at:

https://wiki.wireshark.org/Development/LibpcapFileFormat

Not Saved in the Capture File
You should also know the things that are not saved in capture files:
• Current selections (selected packet, …)
• Name resolution information. See Name Resolution for details
Pcapng files can optionally save name resolution information. Libpcap files can’t. Other file
formats have varying levels of support.

253

• The number of packets dropped while capturing
• Packet marks set with “Edit/Mark Packet”
• Time references set with “Edit/Time Reference”
• The current display filter

Configuration File and Plugin Folders
To match the different policies for Unix-like systems and Windows, and different policies used on
different Unix-like systems, the folders containing configuration files and plugins are different on
different platforms. We indicate the location of the top-level folders under which configuration files
and plugins are stored here, giving them placeholder names independent of their actual location,
and use those names later when giving the location of the folders for configuration files and
plugins.
TIP

A list of the folders Wireshark actually uses can be found under the Folders tab in the
dialog box shown when you select About Wireshark from the Help menu.

Folders on Windows
%APPDATA%

the

personal

application

data

folder,

e.g.:

C:\Users\

username\AppData\Roaming\Wireshark (details can be found at: Windows profiles).
WIRESHARK is the Wireshark program folder, e.g.: C:\Program Files\Wireshark.

Folders on Unix-like systems
$XDG_CONFIG_HOME is the folder for user-specific configuration files. It’s usually $HOME/.config,
where $HOME is the user’s home folder, which is usually something such as $HOME/username, or
/Users/username on macOS.
If you are using macOS and you are running a copy of Wireshark installed as an application bundle,
APPDIR is the top-level directory of the Wireshark application bundle, which will typically be
/Applications/Wireshark.app. Otherwise, INSTALLDIR is the top-level directory under which reside
the subdirectories in which components of Wireshark are installed. This will typically be /usr if
Wireshark is bundled with the system (for example, provided as a package with a Linux
distribution) and /usr/local if, for example, you’ve build Wireshark from source and installed it.

Configuration Files
Wireshark uses a number of configuration files while it is running. Some of these reside in the
personal configuration folder and are used to maintain information between runs of Wireshark,
while some of them are maintained in system areas.

254

The content format of the configuration files is the same on all platforms.
On Windows:
• The personal configuration folder for Wireshark is the Wireshark sub-folder of that folder, i.e.
%APPDATA%\Wireshark.
• The global configuration folder for Wireshark is the Wireshark program folder and is also used
as the system configuration folder.
On Unix-like systems:
• The

personal

configuration

folder

$XDG_CONFIG_HOME/wireshark.

For

backwards

compatibility with Wireshark before 2.2, if $XDG_CONFIG_HOME/wireshark does not exist and
$HOME/.wireshark is present, then the latter will be used.
• If you are using macOS and you are running a copy of Wireshark installed as an application
bundle,

the

global

configuration

folder

APPDIR/Contents/Resources/share/wireshark.

Otherwise, the global configuration folder is INSTALLDIR/share/wireshark.
• The /etc folder is the system configuration folder. The folder actually used on your system may
vary, maybe something like: /usr/local/etc.
Table 25. Configuration files overview

File/Folder

Description

preferences

Settings from the Preferences dialog box.

recent

Recent GUI settings (e.g. recent files lists).

cfilters

Capture filters.

dfilters

Display filters.

colorfilters

Coloring rules.

disabled_protos

Disabled protocols.

ethers

Ethernet name resolution.

manuf

Ethernet name resolution.

hosts

IPv4 and IPv6 name resolution.

services

Network services.

subnets

IPv4 subnet name resolution.

ipxnets

IPX name resolution.

vlans

VLAN ID name resolution.

ss7pcs

SS7 point code resolution.

File contents
preferences

255

This file contains your Wireshark preferences, including defaults for capturing and displaying
packets. It is a simple text file containing statements of the form:

variable: value
At program start, if there is a preferences file in the global configuration folder, it is read first.
Then, if there is a preferences file in the personal configuration folder, that is read; if there is a
preference set in both files, the setting in the personal preferences file overrides the setting in
the global preference file.
If you press the Save button in the “Preferences” dialog box, all the current settings are written
to the personal preferences file.
recent
This file contains various GUI related settings like the main window position and size, the recent
files list and such. It is a simple text file containing statements of the form:

variable: value
It is read at program start and written at program exit.
cfilters
This file contains all the capture filters that you have defined and saved. It consists of one or
more lines, where each line has the following format:

""
At program start, if there is a cfilters file in the personal configuration folder, it is read. If there
isn’t a cfilters file in the personal configuration folder, then, if there is a cfilters file in the global
configuration folder, it is read.
When you press the Save button in the “Capture Filters” dialog box, all the current capture
filters are written to the personal capture filters file.
dfilters
This file contains all the display filters that you have defined and saved. It consists of one or
more lines, where each line has the following format:

""
At program start, if there is a dfilters file in the personal configuration folder, it is read. If there
isn’t a dfilters file in the personal configuration folder, then, if there is a dfilters file in the global

256

configuration folder, it is read.
When you press the Save button in the “Display Filters” dialog box, all the current capture filters
are written to the personal display filters file.
colorfilters
This file contains all the color filters that you have defined and saved. It consists of one or more
lines, where each line has the following format:

@@@[][]
At program start, if there is a colorfilters file in the personal configuration folder, it is read. If
there isn’t a colorfilters file in the personal configuration folder, then, if there is a colorfilters file
in the global configuration folder, it is read.
Wwhen you press the Save button in the “Coloring Rules” dialog box, all the current color filters
are written to the personal color filters file.
disabled_protos
Each line in this file specifies a disabled protocol name. The following are some examples:

tcp
udp
At program start, if there is a disabled_protos file in the global configuration folder, it is read
first. Then, if there is a disabled_protos file in the personal configuration folder, that is read; if
there is an entry for a protocol set in both files, the setting in the personal disabled protocols file
overrides the setting in the global disabled protocols file.
When you press the Save button in the “Enabled Protocols” dialog box, the current set of
disabled protocols is written to the personal disabled protocols file.
ethers
When Wireshark is trying to translate an hardware MAC address to a name, it consults the
ethers file in the personal configuration folder first. If the address is not found in that file,
Wireshark consults the ethers file in the system configuration folder.
Each line in these files consists of one hardware address and name separated by whitespace. The
digits of hardware addresses are separated by colons (:), dashes (-) or periods(.). The following
are some examples:

257

ff-ff-ff-ff-ff-ff
c0-00-ff-ff-ff-ff
00.2b.08.93.4b.a1

Broadcast
TR_broadcast
Freds_machine

The settings from this file are read in when a MAC address is to be translated to a name, and
never written by Wireshark.
manuf
At program start, if there is a manuf file in the global configuration folder, it is read.
The entries in this file are used to translate the first three bytes of an Ethernet address into a
manufacturers name. This file has the same format as the ethers file, except addresses are three
bytes long.
An example is:

00:00:01

Xerox

# XEROX CORPORATION

The settings from this file are read in at program start and never written by Wireshark.
hosts
Wireshark uses the entries in the hosts files to translate IPv4 and IPv6 addresses into names.
At program start, if there is a hosts file in the global configuration folder, it is read first. Then, if
there is a hosts file in the personal configuration folder, that is read; if there is an entry for a
given IP address in both files, the setting in the personal hosts file overrides the entry in the
global hosts file.
This file has the same format as the usual /etc/hosts file on Unix systems.
An example is:

# Comments must be prepended by the # sign!
192.168.0.1 homeserver
The settings from this file are read in at program start and never written by Wireshark.
services
Wireshark uses the services files to translate port numbers into names.
At program start, if there is a services file in the global configuration folder, it is read first. Then,
if there is a services file in the personal configuration folder, that is read; if there is an entry for
a given port number in both files, the setting in the personal hosts file overrides the entry in the
global hosts file.
258

An example is:

mydns
mydns

5045/udp
5045/tcp

# My own Domain Name Server
# My own Domain Name Server

The settings from these files are read in at program start and never written by Wireshark.
subnets
Wireshark uses the subnets files to translate an IPv4 address into a subnet name. If no exact
match from a hosts file or from DNS is found, Wireshark will attempt a partial match for the
subnet of the address.
At program start, if there is a subnets file in the personal configuration folder, it is read first.
Then, if there is a subnets file in the global configuration folder, that is read; if there is a
preference set in both files, the setting in the global preferences file overrides the setting in the
personal preference file.
Each line in one of these files consists of an IPv4 address, a subnet mask length separated only
by a “/” and a name separated by whitespace. While the address must be a full IPv4 address, any
values beyond the mask length are subsequently ignored.
An example is:

# Comments must be prepended by the # sign!
192.168.0.0/24 ws_test_network
A partially matched name will be printed as “subnet-name.remaining-address”. For example,
“192.168.0.1” under the subnet above would be printed as “ws_test_network.1”; if the mask
length above had been 16 rather than 24, the printed address would be “ws_test_network.0.1”.
The settings from these files are read in at program start and never written by Wireshark.
ipxnets
When Wireshark is trying to translate an IPX network number to a name, it consults the ipxnets
file in the personal configuration folder first. If the address is not found in that file, Wireshark
consults the ipxnets file in the system configuration folder.
An example is:

C0.A8.2C.00
c0-a8-1c-00
00:00:BE:EF
110f

HR
CEO
IT_Server1
FileServer3

259

The settings from this file are read in when an IPX network number is to be translated to a
name, and never written by Wireshark.
vlans
Wireshark uses the vlans file to translate VLAN tag IDs into names.
At program start, if there is a vlans file in the personal configuration folder, it is read.
Each line in this file consists of one VLAN tag ID and a describing name separated by whitespace
or tab.
An example is:

123
2049

Server-LAN
HR-Client-LAN

The settings from this file are read in at program start and never written by Wireshark.
ss7pcs
Wireshark uses the ss7pcs file to translate SS7 point codes to node names.
At program start, if there is a ss7pcs file in the personal configuration folder, it is read.
Each line in this file consists of one network indicator followed by a dash followed by a point
code in decimal and a node name separated by whitespace or tab.
An example is:

2-1234 MyPointCode1
The settings from this file are read in at program start and never written by Wireshark.

Plugin folders
Wireshark supports plugins for various purposes. Plugins can either be scripts written in Lua or
code written in C or C++ and compiled to machine code.
Wireshark looks for plugins in both a personal plugin folder and a global plugin folder. Lua plugins
are stored in the plugin folders; compiled plugins are stored in subfolders of the plugin folders,
with the subfolder name being the Wireshark minor version number (X.Y). There is another
hierarchical level for each Wireshark library (libwireshark, libwscodecs and libwiretap). So for
example the location for a libwireshark plugin foo.so (foo.dll on Windows) would be
PLUGINDIR/X.Y/epan (libwireshark used to be called libepan; the other folder names are codecs and
wiretap).

260

On Windows:
• The personal plugin folder is %APPDATA%\Wireshark\plugins.
• The global plugin folder is WIRESHARK\plugins.
On Unix-like systems:
• The personal plugin folder is ~/.local/lib/wireshark/plugins.
To provide better support for binary plugins this folder changed in Wireshark 2.5. It
is recommended to use the new folder but for lua scripts only you may continue to
NOTE

use $XDG_CONFIG_HOME/wireshark/plugins for backward-compatibility. This is
useful to have older versions of Wireshark installed side-by-side. In case of
duplicate file names between old and new the new folder wins.

• If you are running on macOS and Wireshark is installed as an application bundle, the global
plugin

folder

%APPDIR%/Contents/PlugIns/wireshark,

otherwise

it’s

INSTALLDIR/lib/wireshark/plugins.

Windows folders
Here you will find some details about the folders used in Wireshark on different Windows versions.
As already mentioned, you can find the currently used folders in the “About Wireshark” dialog.

Windows profiles
Windows uses some special directories to store user configuration files which define the “user
profile”. This can be confusing, as the default directory location changed from Windows version to
version and might also be different for English and internationalized versions of Windows.
NOTE

If you’ve upgraded to a new Windows version, your profile might be kept in the
former location. The defaults mentioned here might not apply.

The following guides you to the right place where to look for Wireshark’s profile data.
Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Vista, and associated server
editions
C:\Users\username\AppData\Roaming\Wireshark.
Windows XP, Windows Server 2003, and Windows 2000 [1: No longer supported by Wireshark.
For historical reference only.]
C:\Documents

and

Settings\username\Application

Data.

“Documents

and

Settings”

and

“Application Data” might be internationalized.

261

Windows NT 4 [1: No longer supported by Wireshark. For historical reference only.]
C:\WINNT\Profiles\username\Application Data\Wireshark
Windows ME, Windows 98 with user profiles [1: No longer supported by Wireshark. For
historical reference only.]
In Windows ME and 98 you could enable separate user profiles. In that case, something like
C:\windows\Profiles\username\Application Data\Wireshark is used.
Windows ME, Windows 98 without user profiles [1: No longer supported by Wireshark. For
historical reference only.]
Without user profiles enabled the default location for all users was C:\windows\Application
Data\Wireshark.

Windows roaming profiles
Some larger Windows environments use roaming profiles. If this is the case the configurations of
all programs you use won’t be saved on your local hard drive. They will be stored on the domain
server instead.
Your settings will travel with you from computer to computer with one exception. The “Local
Settings” folder in your profile data (typically something like: C:\Documents and Settings\
username\Local Settings) will not be transferred to the domain server. This is the default for
temporary capture files.

Windows temporary folder
Wireshark uses the folder which is set by the TMPDIR or TEMP environment variable. This variable
will be set by the Windows installer.
Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Vista, and associated server
editions
C:\Users\username\AppData\Local\Temp
Windows XP, Windows Server 2003, Windows 2000 [1: No longer supported by Wireshark. For
historical reference only.]
C:\Documents and Settings\username\Local Settings\Temp
Windows NT [1: No longer supported by Wireshark. For historical reference only.]
C:\TEMP

262

Appendix C: Protocols and Protocol Fields
Wireshark distinguishes between protocols (e.g. tcp) and protocol fields (e.g. tcp.port).
A comprehensive list of all protocols and protocol fields can be found in the “Display Filter
Reference” at https://www.wireshark.org/docs/dfref/

263

Appendix D: Related command line tools
Introduction
Along with the main application, Wireshark comes with an array of command line tools which can
be helpful for specialized tasks. Some of these tools will be described in this chapter. You can find
more information about all of Wireshark’s command line tools on the web site.

tshark: Terminal-based Wireshark
TShark is a terminal oriented version of Wireshark designed for capturing and displaying packets
when an interactive user interface isn’t necessary or available. It supports the same options as
wireshark. For more information on tshark consult your local manual page (man tshark) or the
online version.
Help information available from tshark

TShark (Wireshark) 2.9.0-1259-g9e20822a (v2.9.0rc0-1259-g9e20822a)
Dump and analyze network traffic.
See https://www.wireshark.org for more information.
Usage: tshark [options] ...
Capture interface:
-i
-f
-s
-p
-I
-B
-y
--time-stamp-type
-D
-L
--list-time-stamp-types
Capture stop conditions:
-c
-a ...

name or idx of interface (def: first non-loopback)
packet filter in libpcap filter syntax
packet snapshot length (def: appropriate maximum)
don't capture in promiscuous mode
capture in monitor mode, if available
size of kernel buffer (def: 2MB)
link layer type (def: first appropriate)
timestamp method for interface
print list of interfaces and exit
print list of link-layer types of iface and exit
print list of timestamp types for iface and exit

stop after n
duration:NUM
filesize:NUM
files:NUM

packets (def: infinite)
- stop after NUM seconds
- stop this file after NUM KB
- stop after NUM files

Capture output:
-b ... duration:NUM - switch to next file after NUM secs
interval:NUM - create time intervals of NUM secs
filesize:NUM - switch to next file after NUM KB

264

files:NUM - ringbuffer: replace after NUM files
RPCAP options:
-A :
Input file:
-r

use RPCAP password authentication
set the filename to read from (- to read from stdin)

Processing:
-2
-M
-R

perform a two-pass analysis
perform session auto reset
packet Read filter in Wireshark display filter syntax
(requires -2)
-Y
packet displaY filter in Wireshark display filter
syntax
-n
disable all name resolutions (def: all enabled)
-N enable specific name resolution(s): "mnNtCd"
-d ==, ...
"Decode As", see the man page for details
Example: tcp.port==8888,http
-H
read a list of entries from a hosts file, which will
then be written to a capture file. (Implies -W n)
--enable-protocol
enable dissection of proto_name
--disable-protocol
disable dissection of proto_name
--enable-heuristic
enable dissection of heuristic protocol
--disable-heuristic
disable dissection of heuristic protocol
Output:
-w
write packets to a pcap-format file named "outfile"
(or to the standard output for "-")
-C
start with specified configuration profile
-F
set the output file type, default is pcapng
an empty "-F" option will list the file types
-V
add output of packet tree
(Packet Details)
-O
Only show packet details of these protocols, comma
separated
-P
print packet summary even when writing to a file
-S
the line separator to print between packets
-x
add output of hex and ASCII dump (Packet Bytes)
-T pdml|ps|psml|json|jsonraw|ek|tabs|text|fields|?
format of text output (def: text)
-j
protocols layers filter if -T ek|pdml|json selected
(e.g. "ip ip.flags text", filter does not expand child
nodes, unless child is specified also in the filter)
-J
top level protocol filter if -T ek|pdml|json selected
(e.g. "http tcp", filter which expands all child nodes)
-e
field to print if -Tfields selected (e.g. tcp.port,

265

_ws.col.Info)
this option can be repeated to print multiple fields
-E= set options for output when -Tfields selected:
bom=y|n
print a UTF-8 BOM
header=y|n
switch headers on and off
separator=/t|/s| select tab, space, printable character as separator
occurrence=f|l|a
print first, last or all occurrences of each field
aggregator=,|/s| select comma, space, printable character as
aggregator
quote=d|s|n
select double, single, no quotes for values
-t a|ad|d|dd|e|r|u|ud|? output format of time stamps (def: r: rel. to first)
-u s|hms
output format of seconds (def: s: seconds)
-l
flush standard output after each packet
-q
be more quiet on stdout (e.g. when using statistics)
-Q
only log true errors to stderr (quieter than -q)
-g
enable group read access on the output file(s)
-W n
Save extra information in the file, if supported.
n = write network address resolution information
-X :
eXtension options, see the man page for details
-U tap_name
PDUs export mode, see the man page for details
-z
various statistics, see the man page for details
--capture-comment
add a capture comment to the newly created
output file (only for pcapng)
--export-objects , save exported objects for a protocol to
a directory named "destdir"
--color
color output text similarly to the Wireshark GUI,
requires a terminal with 24-bit color support
Also supplies color attributes to pdml and psml formats
(Note that attributes are nonstandard)
--no-duplicate-keys
If -T json is specified, merge duplicate keys in an object
into a single key with as value a json array containing all
values
--elastic-mapping-filter If -G elastic-mapping is specified, put only
the
specified protocols within the mapping file
Miscellaneous:
-h
-v
-o : ...
-K
-G [report]

266

display this help and exit
display version info and exit
override preference setting
keytab file to use for kerberos decryption
dump one of several available reports and exit
default report="fields"
use "-G help" for more help

tcpdump: Capturing with “tcpdump” for viewing with
Wireshark
It’s often more useful to capture packets using tcpdump rather than wireshark. For example, you
might want to do a remote capture and either don’t have GUI access or don’t have Wireshark
installed on the remote machine.
Older versions of tcpdump truncate packets to 68 or 96 bytes. If this is the case, use -s to capture fullsized packets:

$ tcpdump -i -s 65535 -w
You will have to specify the correct interface and the name of a file to save into. In addition, you will
have to terminate the capture with ^C when you believe you have captured enough packets.
tcpdump is not part of the Wireshark distribution. You can get it from http://www.tcpdump.org/ or as
a standard package in most Linux distributions. For more information on tcpdump consult your local
manual page (man tcpdump) or the online version.

dumpcap: Capturing with “dumpcap” for viewing with
Wireshark
Dumpcap is a network traffic dump tool. It captures packet data from a live network and writes the
packets to a file. Dumpcap’s native capture file format is pcapng, which is also the format used by
Wireshark.
Without any options set it will use the pcap library to capture traffic from the first available
network interface and write the received raw packet data, along with the packets’ time stamps into
a pcapng file. The capture filter syntax follows the rules of the pcap library. For more information
on dumpcap consult your local manual page (man dumpcap) or the online version.
Help information available from dumpcap

Dumpcap (Wireshark) 2.9.0-1259-g9e20822a (v2.9.0rc0-1259-g9e20822a)
Capture network packets and dump them into a pcapng or pcap file.
See https://www.wireshark.org for more information.
Usage: dumpcap [options] ...
Capture interface:
-i

name or idx of interface (def: first non-loopback),
or for remote capturing, use one of these formats:
rpcap:///
TCP@:

267

-f
-s
-p
-I
-B
-y
--time-stamp-type
-D
-L
--list-time-stamp-types
-d
-k
-S
-M
RPCAP options:
-r
-u
-A :
-m

Stop conditions:
-c
-a ...

packet filter in libpcap filter syntax
packet snapshot length (def: appropriate maximum)
don't capture in promiscuous mode
capture in monitor mode, if available
size of kernel buffer in MiB (def: 2MiB)
link layer type (def: first appropriate)
timestamp method for interface
print list of interfaces and exit
print list of link-layer types of iface and exit
print list of timestamp types for iface and exit
print generated BPF code for capture filter
set channel on wifi interface:
,[],[],[]
print statistics for each interface once per second
for -D, -L, and -S, produce machine-readable output

don't ignore own RPCAP traffic in capture
use UDP for RPCAP data transfer
use RPCAP password authentication
use packet sampling
count:NUM - capture one packet of every NUM
timer:NUM - capture no more than 1 packet in NUM ms
stop after n
duration:NUM
filesize:NUM
files:NUM

packets (def: infinite)
- stop after NUM seconds
- stop this file after NUM KB
- stop after NUM files

Output (files):
-w
name of file to save (def: tempfile)
-g
enable group read access on the output file(s)
-b ... duration:NUM - switch to next file after NUM secs
interval:NUM - create time intervals of NUM secs
filesize:NUM - switch to next file after NUM KB
files:NUM - ringbuffer: replace after NUM files
-n
use pcapng format instead of pcap (default)
-P
use libpcap format instead of pcapng
--capture-comment
add a capture comment to the output file
(only for pcapng)
Miscellaneous:
-N
-C
-t
-q
-v

268

maximum number of packets buffered within dumpcap
maximum number of bytes used for buffering packets
within dumpcap
use a separate thread per interface
don't report packet capture counts
print version information and exit

-h

display this help and exit

Example: dumpcap -i eth0 -a duration:60 -w output.pcapng
"Capture packets from interface eth0 until 60s passed into output.pcapng"
Use Ctrl-C to stop capturing at any time.

capinfos: Print information about capture files
capinfos can print information about capture files including the file type, number of packets, date
and time information, and file hashes. Information can be printed in human and machine readable
formats. For more information on capinfos consult your local manual page (man capinfos) or the
online version.
Help information available from capinfos

Capinfos (Wireshark) 2.9.0-1259-g9e20822a (v2.9.0rc0-1259-g9e20822a)
Print various information (infos) about capture files.
See https://www.wireshark.org for more information.
Usage: capinfos [options] ...
General infos:
-t display the capture file type
-E display the capture file encapsulation
-I display the capture file interface information
-F display additional capture file information
-H display the SHA256, RMD160, and SHA1 hashes of the file
-k display the capture comment
Size
-c
-s
-d
-l

infos:
display
display
display
display

the
the
the
the

Time
-u
-a
-e
-o
-S

infos:
display
display
display
display
display

the capture duration (in seconds)
the capture start time
the capture end time
the capture file chronological status (True/False)
start and end times as seconds

number of packets
size of the file (in bytes)
total length of all packets (in bytes)
packet size limit (snapshot length)

Statistic infos:
-y display average data rate (in bytes/sec)
-i display average data rate (in bits/sec)

269

-z display average packet size (in bytes)
-x display average packet rate (in packets/sec)
Output format:
-L generate long report (default)
-T generate table report
-M display machine-readable values in long reports
Table report options:
-R generate header record (default)
-r do not generate header record
-B separate infos with TAB character (default)
-m separate infos with comma (,) character
-b separate infos with SPACE character
-N do not quote infos (default)
-q quote infos with single quotes (')
-Q quote infos with double quotes (")
Miscellaneous:
-h display this help and exit
-C cancel processing if file open fails (default is to continue)
-A generate all infos (default)
-K disable displaying the capture comment
Options are processed from left to right order with later options superceding
or adding to earlier options.
If no options are given the default is to display all infos in long report
output format.

rawshark: Dump and analyze network traffic.
Rawshark reads a stream of packets from a file or pipe, and prints a line describing its output,
followed by a set of matching fields for each packet on stdout. For more information on rawshark
consult your local manual page (man rawshark) or the online version.

270

Help information available from rawshark

Rawshark (Wireshark) 2.9.0-1259-g9e20822a (v2.9.0rc0-1259-g9e20822a)
Dump and analyze network traffic.
See https://www.wireshark.org for more information.
Usage: rawshark [options] ...
Input file:
-r

set the pipe or file name to read from

Processing:
-d |
packet encapsulation or protocol
-F
field to display
-n
disable all name resolution (def: all enabled)
-N enable specific name resolution(s): "mnNtd"
-p
use the system's packet header format
(which may have 64-bit timestamps)
-R
packet filter in Wireshark display filter syntax
-s
skip PCAP header on input
Output:
-l
-S
-t ad|a|r|d|dd|e
Miscellaneous:
-h
-o : ...
-v

flush output after each packet
format string for fields
(%D - name, %S - stringval, %N numval)
output format of time stamps (def: r: rel. to first)

display this help and exit
override preference setting
display version info and exit

editcap: Edit capture files
editcap is a general-purpose utility for modifying capture files. Its main function is to remove
packets from capture files, but it can also be used to convert capture files from one format to
another, as well as to print information about capture files. For more information on editcap
consult your local manual page (man editcap) or the online version.
Help information available from editcap

Editcap (Wireshark) 2.9.0-1259-g9e20822a (v2.9.0rc0-1259-g9e20822a)
Edit and/or translate the format of capture files.
See https://www.wireshark.org for more information.

271

Usage: editcap [options] ... [ [-] ... ]
and must both be present.
A single packet or a range of packets can be selected.
Packet selection:
-r
-A
-B

keep the selected packets; default is to delete them.
only output packets whose timestamp is after (or equal
to) the given time (format as YYYY-MM-DD hh:mm:ss).
only output packets whose timestamp is before the
given time (format as YYYY-MM-DD hh:mm:ss).

Duplicate packet removal:
--novlan
remove vlan info from packets before checking for duplicates.
-d
remove packet if duplicate (window == 5).
-D
remove packet if duplicate; configurable .
Valid values are 0 to 1000000.
NOTE: A of 0 with -v (verbose option) is
useful to print MD5 hashes.
-w
remove packet if duplicate packet is found EQUAL TO OR
LESS THAN prior to current packet.
A is specified in relative seconds
(e.g. 0.000001).
NOTE: The use of the 'Duplicate packet removal' options with
other editcap options except -v may not always work as expected.
Specifically the -r, -t or -S options will very likely NOT have the
desired effect if combined with the -d, -D or -w.
Packet manipulation:
-s
-C [offset:]

truncate each packet to max. bytes of data.
chop each packet by bytes. Positive values
chop at the packet beginning, negative values at the
packet end. If an optional offset precedes the length,
then the bytes chopped will be offset from that value.
Positive offsets are from the packet beginning,
negative offsets are from the packet end. You can use
this option more than once, allowing up to 2 chopping
regions within a packet provided that at least 1
choplen is positive and at least 1 is negative.
-L
adjust the frame (i.e. reported) length when chopping
and/or snapping.
-t
adjust the timestamp of each packet.
is in relative seconds (e.g. -0.5).
-S adjust timestamp of packets if necessary to ensure
strict chronological increasing order. The is specified in relative seconds with
values of 0 or 0.000001 being the most reasonable.
A negative adjustment value will modify timestamps so

272

-E
-o

-I

-a

that each packet's delta time is the absolute value
of the adjustment specified. A value of -0 will set
all packets to the timestamp of the first packet.
set the probability (between 0.0 and 1.0 incl.) that
a particular packet byte will be randomly changed.

When used in conjunction with -E, skip some bytes from the
beginning of the packet. This allows one to preserve some
bytes, in order to have some headers untouched.

ignore the specified number of bytes at the beginning
of the frame during MD5 hash calculation, unless the
frame is too short, then the full frame is used.
Useful to remove duplicated packets taken on
several routers (different mac addresses for
example).
e.g. -I 26 in case of Ether/IP will ignore
ether(14) and IP header(20 - 4(src ip) - 4(dst ip)).
: Add or replace comment for given frame number

Output File(s):
-c

-i

-F
-T

Miscellaneous:
-h
-v

split the packet output to different files based on
uniform packet counts with a maximum of
each.
split the packet output to different files based on
uniform time intervals with a maximum of
each.
set the output file type; default is pcapng. An empty
"-F" option will list the file types.
set the output file encapsulation type; default is the
same as the input file. An empty "-T" option will
list the encapsulation types.

display this help and exit.
verbose output.
If -v is used with any of the 'Duplicate Packet
Removal' options (-d, -D or -w) then Packet lengths
and MD5 hashes are printed to standard-error.

273

Capture file types available from editcap -F

editcap: The available capture file types for the "-F" flag are:
5views - InfoVista 5View capture
btsnoop - Symbian OS btsnoop
commview - TamoSoft CommView
dct2000 - Catapult DCT2000 trace (.out format)
erf - Endace ERF capture
eyesdn - EyeSDN USB S0/E1 ISDN trace format
k12text - K12 text file
lanalyzer - Novell LANalyzer
logcat - Android Logcat Binary format
logcat-brief - Android Logcat Brief text format
logcat-long - Android Logcat Long text format
logcat-process - Android Logcat Process text format
logcat-tag - Android Logcat Tag text format
logcat-thread - Android Logcat Thread text format
logcat-threadtime - Android Logcat Threadtime text format
logcat-time - Android Logcat Time text format
modpcap - Modified tcpdump - pcap
netmon1 - Microsoft NetMon 1.x
netmon2 - Microsoft NetMon 2.x
nettl - HP-UX nettl trace
ngsniffer - Sniffer (DOS)
ngwsniffer_1_1 - NetXray, Sniffer (Windows) 1.1
ngwsniffer_2_0 - Sniffer (Windows) 2.00x
niobserver - Network Instruments Observer
nokiapcap - Nokia tcpdump - pcap
nsecpcap - Wireshark/tcpdump/... - nanosecond pcap
nstrace10 - NetScaler Trace (Version 1.0)
nstrace20 - NetScaler Trace (Version 2.0)
nstrace30 - NetScaler Trace (Version 3.0)
nstrace35 - NetScaler Trace (Version 3.5)
pcap - Wireshark/tcpdump/... - pcap
pcapng - Wireshark/... - pcapng
rf5 - Tektronix K12xx 32-bit .rf5 format
rh6_1pcap - RedHat 6.1 tcpdump - pcap
snoop - Sun snoop
suse6_3pcap - SuSE 6.3 tcpdump - pcap
visual - Visual Networks traffic capture
Encapsulation types available from editcap -T

editcap: The available encapsulation types for the "-T" flag are:
ap1394 - Apple IP-over-IEEE 1394
arcnet - ARCNET
arcnet_linux - Linux ARCNET

274

ascend - Lucent/Ascend access equipment
atm-pdus - ATM PDUs
atm-pdus-untruncated - ATM PDUs - untruncated
atm-rfc1483 - RFC 1483 ATM
ax25 - Amateur Radio AX.25
ax25-kiss - AX.25 with KISS header
bacnet-ms-tp - BACnet MS/TP
bacnet-ms-tp-with-direction - BACnet MS/TP with Directional Info
ber - ASN.1 Basic Encoding Rules
bluetooth-bredr-bb-rf - Bluetooth BR/EDR Baseband RF
bluetooth-h4 - Bluetooth H4
bluetooth-h4-linux - Bluetooth H4 with linux header
bluetooth-hci - Bluetooth without transport layer
bluetooth-le-ll - Bluetooth Low Energy Link Layer
bluetooth-le-ll-rf - Bluetooth Low Energy Link Layer RF
bluetooth-linux-monitor - Bluetooth Linux Monitor
can20b - Controller Area Network 2.0B
chdlc - Cisco HDLC
chdlc-with-direction - Cisco HDLC with Directional Info
cosine - CoSine L2 debug log
dbus - D-Bus
dct2000 - Catapult DCT2000
docsis - Data Over Cable Service Interface Specification
docsis31_xra31 - DOCSIS with Excentis XRA pseudo-header
dpauxmon - DisplayPort AUX channel with Unigraf pseudo-header
dpnss_link - Digital Private Signalling System No 1 Link Layer
dvbci - DVB-CI (Common Interface)
enc - OpenBSD enc(4) encapsulating interface
epon - Ethernet Passive Optical Network
erf - Extensible Record Format
ether - Ethernet
ether-mpacket - IEEE 802.3br mPackets
ether-nettl - Ethernet with nettl headers
fc2 - Fibre Channel FC-2
fc2sof - Fibre Channel FC-2 With Frame Delimiter
fddi - FDDI
fddi-nettl - FDDI with nettl headers
fddi-swapped - FDDI with bit-swapped MAC addresses
flexray - FlexRay
frelay - Frame Relay
frelay-with-direction - Frame Relay with Directional Info
gcom-serial - GCOM Serial
gcom-tie1 - GCOM TIE1
gfp-f - ITU-T G.7041/Y.1303 Generic Framing Procedure Frame-mapped mode
gfp-t - ITU-T G.7041/Y.1303 Generic Framing Procedure Transparent mode
gprs-llc - GPRS LLC
gsm_um - GSM Um Interface
hhdlc - HiPath HDLC

275

i2c - I2C
ieee-802-11 - IEEE 802.11 Wireless LAN
ieee-802-11-avs - IEEE 802.11 plus AVS radio header
ieee-802-11-netmon - IEEE 802.11 plus Network Monitor radio header
ieee-802-11-prism - IEEE 802.11 plus Prism II monitor mode radio header
ieee-802-11-radio - IEEE 802.11 Wireless LAN with radio information
ieee-802-11-radiotap - IEEE 802.11 plus radiotap radio header
ieee-802-16-mac-cps - IEEE 802.16 MAC Common Part Sublayer
infiniband - InfiniBand
ios - Cisco IOS internal
ip-ib - IP over IB
ip-over-fc - RFC 2625 IP-over-Fibre Channel
ip-over-ib - IP over Infiniband
ipfix - IPFIX
ipmb - Intelligent Platform Management Bus
ipmi-trace - IPMI Trace Data Collection
ipnet - Solaris IPNET
irda - IrDA
isdn - ISDN
iso14443 - ISO 14443 contactless smartcard standards
ixveriwave - IxVeriWave header and stats block
jfif - JPEG/JFIF
json - JavaScript Object Notation
juniper-atm1 - Juniper ATM1
juniper-atm2 - Juniper ATM2
juniper-chdlc - Juniper C-HDLC
juniper-ether - Juniper Ethernet
juniper-frelay - Juniper Frame-Relay
juniper-ggsn - Juniper GGSN
juniper-mlfr - Juniper MLFR
juniper-mlppp - Juniper MLPPP
juniper-ppp - Juniper PPP
juniper-pppoe - Juniper PPPoE
juniper-st - Juniper Secure Tunnel Information
juniper-svcs - Juniper Services
juniper-vn - Juniper VN
juniper-vp - Juniper Voice PIC
k12 - K12 protocol analyzer
lapb - LAPB
lapd - LAPD
layer1-event - EyeSDN Layer 1 event
lin - Local Interconnect Network
linux-atm-clip - Linux ATM CLIP
linux-lapd - LAPD with Linux pseudo-header
linux-sll - Linux cooked-mode capture
logcat - Android Logcat Binary format
logcat_brief - Android Logcat Brief text format
logcat_long - Android Logcat Long text format

276

logcat_process - Android Logcat Process text format
logcat_tag - Android Logcat Tag text format
logcat_thread - Android Logcat Thread text format
logcat_threadtime - Android Logcat Threadtime text format
logcat_time - Android Logcat Time text format
loop - OpenBSD loopback
loratap - LoRaTap
ltalk - Localtalk
message_analyzer_wfp_capture2_v4 - Message Analyzer WFP Capture2 v4
message_analyzer_wfp_capture2_v6 - Message Analyzer WFP Capture2 v6
message_analyzer_wfp_capture_auth_v4 - Message Analyzer WFP Capture Auth v4
message_analyzer_wfp_capture_auth_v6 - Message Analyzer WFP Capture Auth v6
message_analyzer_wfp_capture_v4 - Message Analyzer WFP Capture v4
message_analyzer_wfp_capture_v6 - Message Analyzer WFP Capture v6
mime - MIME
most - Media Oriented Systems Transport
mp2ts - ISO/IEC 13818-1 MPEG2-TS
mpeg - MPEG
mtp2 - SS7 MTP2
mtp2-with-phdr - MTP2 with pseudoheader
mtp3 - SS7 MTP3
mux27010 - MUX27010
netanalyzer - netANALYZER
netanalyzer-transparent - netANALYZER-Transparent
netlink - Linux Netlink
netmon_event - Network Monitor Network Event
netmon_filter - Network Monitor Filter
netmon_header - Network Monitor Header
netmon_network_info - Network Monitor Network Info
nfc-llcp - NFC LLCP
nflog - NFLOG
nordic_ble - Nordic BLE Sniffer
nstrace10 - NetScaler Encapsulation 1.0 of Ethernet
nstrace20 - NetScaler Encapsulation 2.0 of Ethernet
nstrace30 - NetScaler Encapsulation 3.0 of Ethernet
nstrace35 - NetScaler Encapsulation 3.5 of Ethernet
null - NULL/Loopback
packetlogger - PacketLogger
pflog - OpenBSD PF Firewall logs
pflog-old - OpenBSD PF Firewall logs, pre-3.4
pktap - Apple PKTAP
ppi - Per-Packet Information header
ppp - PPP
ppp-with-direction - PPP with Directional Info
pppoes - PPP-over-Ethernet session
raw-icmp-nettl - Raw ICMP with nettl headers
raw-icmpv6-nettl - Raw ICMPv6 with nettl headers
raw-telnet-nettl - Raw telnet with nettl headers

277

rawip - Raw IP
rawip-nettl - Raw IP with nettl headers
rawip4 - Raw IPv4
rawip6 - Raw IPv6
redback - Redback SmartEdge
rtac-serial - RTAC serial-line
s4607 - STANAG 4607
s5066-dpdu - STANAG 5066 Data Transfer Sublayer PDUs(D_PDU)
sccp - SS7 SCCP
sctp - SCTP
sdh - SDH
sdlc - SDLC
sita-wan - SITA WAN packets
slip - SLIP
socketcan - SocketCAN
symantec - Symantec Enterprise Firewall
tnef - Transport-Neutral Encapsulation Format
tr - Token Ring
tr-nettl - Token Ring with nettl headers
tzsp - Tazmen sniffer protocol
unknown - Unknown
unknown-nettl - Unknown link-layer type with nettl headers
usb-darwin - USB packets with Darwin (macOS, etc.) headers
usb-freebsd - USB packets with FreeBSD header
usb-linux - USB packets with Linux header
usb-linux-mmap - USB packets with Linux header and padding
usb-usbpcap - USB packets with USBPcap header
user0 - USER 0
user1 - USER 1
user2 - USER 2
user3 - USER 3
user4 - USER 4
user5 - USER 5
user6 - USER 6
user7 - USER 7
user8 - USER 8
user9 - USER 9
user10 - USER 10
user11 - USER 11
user12 - USER 12
user13 - USER 13
user14 - USER 14
user15 - USER 15
v5-ef - V5 Envelope Function
vsock - Linux vsock
whdlc - Wellfleet HDLC
wireshark-upper-pdu - Wireshark Upper PDU export
wpan - IEEE 802.15.4 Wireless PAN

278

wpan-nofcs - IEEE 802.15.4 Wireless PAN with FCS not present
wpan-nonask-phy - IEEE 802.15.4 Wireless PAN non-ASK PHY
x2e-serial - X2E serial line capture
x2e-xoraya - X2E Xoraya
x25-nettl - X.25 with nettl headers
xeth - Xerox 3MB Ethernet

mergecap: Merging multiple capture files into one
Mergecap is a program that combines multiple saved capture files into a single output file specified
by the -w argument. Mergecap knows how to read libpcap capture files, including those of tcpdump.
In addition, Mergecap can read capture files from snoop (including Shomiti) and atmsnoop,
LanAlyzer, Sniffer (compressed or uncompressed), Microsoft Network Monitor, AIX’s iptrace,
NetXray, Sniffer Pro, RADCOM’s WAN/LAN analyzer, Lucent/Ascend router debug output, HP-UX’s
nettl, and the dump output from Toshiba’s ISDN routers. There is no need to tell Mergecap what
type of file you are reading; it will determine the file type by itself. Mergecap is also capable of
reading any of these file formats if they are compressed using gzip. Mergecap recognizes this
directly from the file; the “.gz” extension is not required for this purpose.
By default, it writes the capture file in pcapng format, and writes all of the packets in the input
capture files to the output file. The -F flag can be used to specify the format in which to write the
capture file; it can write the file in libpcap format (standard libpcap format, a modified format used
by some patched versions of libpcap, the format used by Red Hat Linux 6.1, or the format used by
SuSE Linux 6.3), snoop format, uncompressed Sniffer format, Microsoft Network Monitor 1.x
format, and the format used by Windows-based versions of the Sniffer software.
Packets from the input files are merged in chronological order based on each frame’s timestamp,
unless the -a flag is specified. Mergecap assumes that frames within a single capture file are
already stored in chronological order. When the -a flag is specified, packets are copied directly
from each input file to the output file, independent of each frame’s timestamp.
If the -s flag is used to specify a snapshot length, frames in the input file with more captured data
than the specified snapshot length will have only the amount of data specified by the snapshot
length written to the output file. This may be useful if the program that is to read the output file
cannot handle packets larger than a certain size (for example, the versions of snoop in Solaris 2.5.1
and Solaris 2.6 appear to reject Ethernet frames larger than the standard Ethernet MTU, making
them incapable of handling gigabit Ethernet captures if jumbo frames were used).
If the -T flag is used to specify an encapsulation type, the encapsulation type of the output capture
file will be forced to the specified type, rather than being the type appropriate to the encapsulation
type of the input capture file. Note that this merely forces the encapsulation type of the output file
to be the specified type; the packet headers of the packets will not be translated from the
encapsulation type of the input capture file to the specified encapsulation type (for example, it will
not translate an Ethernet capture to an FDDI capture if an Ethernet capture is read and -T fddi is
specified).

279

For more information on mergecap consult your local manual page (man mergecap) or the online
version.
Help information available from mergecap

Mergecap (Wireshark) 2.9.0-1259-g9e20822a (v2.9.0rc0-1259-g9e20822a)
Merge two or more capture files into one.
See https://www.wireshark.org for more information.
Usage: mergecap [options] -w |- [ ...]
Output:
-a

concatenate rather than merge files.
default is to merge based on frame timestamps.
-s
truncate packets to bytes of data.
-w |set the output filename to or '-' for stdout.
-F set the output file type; default is pcapng.
an empty "-F" option will list the file types.
-I set the merge mode for Interface Description Blocks; default is
'all'.
an empty "-I" option will list the merge modes.
Miscellaneous:
-h
-v

display this help and exit.
verbose output.

A simple example merging dhcp-capture.pcapng and imap-1.pcapng into outfile.pcapng is shown
below.
Simple example of using mergecap

$ mergecap -w outfile.pcapng dhcp-capture.pcapng imap-1.pcapng

text2pcap: Converting ASCII hexdumps to network
captures
There may be some occasions when you wish to convert a hex dump of some network traffic into a
libpcap file.
text2pcap is a program that reads in an ASCII hex dump and writes the data described into a
libpcap-style capture file. text2pcap can read hexdumps with multiple packets in them, and build a
capture file of multiple packets. text2pcap is also capable of generating dummy Ethernet, IP and
UDP headers, in order to build fully processable packet dumps from hexdumps of application-level
data only.

280

text2pcap understands a hexdump of the form generated by od -A x -t x1. In other words, each
byte is individually displayed and surrounded with a space. Each line begins with an offset
describing the position in the file. The offset is a hex number (can also be octal - see -o), of more
than two hex digits. Here is a sample dump that text2pcap can recognize:

000000
000008
000010
000018
000020
000028
000030

00
5a
03
ee
03
16
01

e0
a0
68
33
80
a2
01

1e
b9
00
0f
94
0a
0f

a7
12
00
19
04
00
19

05
08
00
08
00
03
03

6f
00
00
7f
00
50
80

00
46
0a
0f
10
00
11

10
00
2e
19
01
0c
01

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

There is no limit on the width or number of bytes per line. Also the text dump at the end of the line
is ignored. Bytes/hex numbers can be uppercase or lowercase. Any text before the offset is ignored,
including email forwarding characters “>”. Any lines of text between the bytestring lines is ignored.
The offsets are used to track the bytes, so offsets must be correct. Any line which has only bytes
without a leading offset is ignored. An offset is recognized as being a hex number longer than two
characters. Any text after the bytes is ignored (e.g. the character dump). Any hex numbers in this
text are also ignored. An offset of zero is indicative of starting a new packet, so a single text file with
a series of hexdumps can be converted into a packet capture with multiple packets. Multiple
packets are read in with timestamps differing by one second each. In general, short of these
restrictions, text2pcap is pretty liberal about reading in hexdumps and has been tested with a
variety of mangled outputs (including being forwarded through email multiple times, with limited
line wrap etc.)
There are a couple of other special features to note. Any line where the first non-whitespace
character is “#” will be ignored as a comment. Any line beginning with #TEXT2PCAP is a directive
and options can be inserted after this command to be processed by text2pcap. Currently there are
no directives implemented; in the future, these may be used to give more fine grained control on
the dump and the way it should be processed e.g. timestamps, encapsulation type etc.
text2pcap also allows the user to read in dumps of application-level data, by inserting dummy L2,
L3 and L4 headers before each packet. Possibilities include inserting headers such as Ethernet,
Ethernet + IP, Ethernet + IP + UDP, or Ethernet + Ip + TCP before each packet. This allows Wireshark
or any other full-packet decoder to handle these dumps.
For more information on text2pcap consult your local manual page (man text2pcap) or the online
version.
Help information available from text2pcap

Text2pcap (Wireshark) 2.9.0-1259-g9e20822a (v2.9.0rc0-1259-g9e20822a)
Generate a capture file from an ASCII hexdump of packets.
See https://www.wireshark.org for more information.

281

Usage: text2pcap [options]
where

specifies input filename (use - for standard input)
specifies output filename (use - for standard output)

Input:
-o hex|oct|dec
-t

-D

-a

Output:
-l

-m
Prepend dummy header:
-e

-i

-4 ,

282

parse offsets as (h)ex, (o)ctal or (d)ecimal;
default is hex.
treat the text before the packet as a date/time code;
the specified argument is a format string of the sort
supported by strptime.
Example: The time "10:15:14.5476" has the format code
"%H:%M:%S."
NOTE: The subsecond component delimiter, '.', must be
given, but no pattern is required; the remaining
number is assumed to be fractions of a second.
NOTE: Date/time fields from the current date/time are
used as the default for unspecified fields.
the text before the packet starts with an I or an O,
indicating that the packet is inbound or outbound.
This is only stored if the output format is pcapng.
enable ASCII text dump identification.
The start of the ASCII text dump can be identified
and excluded from the packet data, even if it looks
like a HEX dump.
NOTE: Do not enable it if the input file does not
contain the ASCII text dump.

link-layer type number; default is 1 (Ethernet). See
http://www.tcpdump.org/linktypes.html for a list of
numbers. Use this option if your dump is a complete
hex dump of an encapsulated packet and you wish to
specify the exact type of encapsulation.
Example: -l 7 for ARCNet packets.
max packet length in output; default is 262144

prepend dummy Ethernet II header with specified L3PID
(in HEX).
Example: -e 0x806 to specify an ARP packet.
prepend dummy IP header with specified IP protocol
(in DECIMAL).
Automatically prepends Ethernet header as well.
Example: -i 46
prepend dummy IPv4 header with specified
dest and source address.

Example: -4 10.0.0.1,10.0.0.2
-6 ,
replace IPv6 header with specified
dest and source address.
Example: -6
fe80:0:0:0:202:b3ff:fe1e:8329,2001:0db8:85a3:0000:0000:8a2e:0370:7334
-u ,
prepend dummy UDP header with specified
source and destination ports (in DECIMAL).
Automatically prepends Ethernet & IP headers as well.
Example: -u 1000,69 to make the packets look like
TFTP/UDP packets.
-T ,
prepend dummy TCP header with specified
source and destination ports (in DECIMAL).
Automatically prepends Ethernet & IP headers as well.
Example: -T 50,60
-s ,, prepend dummy SCTP header with specified
source/dest ports and verification tag (in DECIMAL).
Automatically prepends Ethernet & IP headers as well.
Example: -s 30,40,34
-S ,, prepend dummy SCTP header with specified
source/dest ports and verification tag 0.
Automatically prepends a dummy SCTP DATA
chunk header with payload protocol identifier ppi.
Example: -S 30,40,34
Miscellaneous:
-h
-d
-q
-n

display this help and exit.
show detailed debug of parser states.
generate no output at all (automatically disables -d).
use pcapng instead of pcap as output format.

reordercap: Reorder a capture file
reordercap lets you reorder a capture file according to the packets timestamp. For more information
on reordercap consult your local manual page (man reordercap) or the online version.
Help information available from reordercap

Reordercap (Wireshark) 2.9.0-1259-g9e20822a (v2.9.0rc0-1259-g9e20822a)
Reorder timestamps of input file frames into output file.
See https://www.wireshark.org for more information.
Usage: reordercap [options]
Options:
-n
-h

don't write to output file if the input file is ordered.
display this help and exit.

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This Document’s License (GPL)
As with the original license and documentation distributed with Wireshark, this document is
covered by the GNU General Public License (GNU GPL).
If you haven’t read the GPL before, please do so. It explains all the things that you are allowed to do
with this code and documentation.

GNU GENERAL PUBLIC LICENSE
Version 2, June 1991
Copyright (C) 1989, 1991 Free
51 Franklin Street, Fifth
Everyone is permitted to copy
of this license document, but

Software Foundation, Inc.
Floor, Boston, MA 02110-1301 USA
and distribute verbatim copies
changing it is not allowed.

Preamble
The licenses for most software are designed to take away your
freedom to share and change it. By contrast, the GNU General Public
License is intended to guarantee your freedom to share and change free
software--to make sure the software is free for all its users. This
General Public License applies to most of the Free Software
Foundation's software and to any other program whose authors commit to
using it. (Some other Free Software Foundation software is covered by
the GNU Library General Public License instead.) You can apply it to
your programs, too.
When we speak of free software, we are referring to freedom, not
price. Our General Public Licenses are designed to make sure that you
have the freedom to distribute copies of free software (and charge for
this service if you wish), that you receive source code or can get it
if you want it, that you can change the software or use pieces of it
in new free programs; and that you know you can do these things.
To protect your rights, we need to make restrictions that forbid
anyone to deny you these rights or to ask you to surrender the rights.
These restrictions translate to certain responsibilities for you if you
distribute copies of the software, or if you modify it.
For example, if you distribute copies of such a program, whether
gratis or for a fee, you must give the recipients all the rights that
you have. You must make sure that they, too, receive or can get the
source code. And you must show them these terms so they know their
rights.

284

We protect your rights with two steps: (1) copyright the software, and
(2) offer you this license which gives you legal permission to copy,
distribute and/or modify the software.
Also, for each author's protection and ours, we want to make certain
that everyone understands that there is no warranty for this free
software. If the software is modified by someone else and passed on, we
want its recipients to know that what they have is not the original, so
that any problems introduced by others will not reflect on the original
authors' reputations.
Finally, any free program is threatened constantly by software
patents. We wish to avoid the danger that redistributors of a free
program will individually obtain patent licenses, in effect making the
program proprietary. To prevent this, we have made it clear that any
patent must be licensed for everyone's free use or not licensed at all.
The precise terms and conditions for copying, distribution and
modification follow.
GNU GENERAL PUBLIC LICENSE
TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
0. This License applies to any program or other work which contains
a notice placed by the copyright holder saying it may be distributed
under the terms of this General Public License. The "Program", below,
refers to any such program or work, and a "work based on the Program"
means either the Program or any derivative work under copyright law:
that is to say, a work containing the Program or a portion of it,
either verbatim or with modifications and/or translated into another
language. (Hereinafter, translation is included without limitation in
the term "modification".) Each licensee is addressed as "you".
Activities other than copying, distribution and modification are not
covered by this License; they are outside its scope. The act of
running the Program is not restricted, and the output from the Program
is covered only if its contents constitute a work based on the
Program (independent of having been made by running the Program).
Whether that is true depends on what the Program does.
1. You may copy and distribute verbatim copies of the Program's
source code as you receive it, in any medium, provided that you
conspicuously and appropriately publish on each copy an appropriate
copyright notice and disclaimer of warranty; keep intact all the
notices that refer to this License and to the absence of any warranty;
and give any other recipients of the Program a copy of this License
along with the Program.

285

You may charge a fee for the physical act of transferring a copy, and
you may at your option offer warranty protection in exchange for a fee.
2. You may modify your copy or copies of the Program or any portion
of it, thus forming a work based on the Program, and copy and
distribute such modifications or work under the terms of Section 1
above, provided that you also meet all of these conditions:
a) You must cause the modified files to carry prominent notices
stating that you changed the files and the date of any change.
b) You must cause any work that
whole or in part contains or is
part thereof, to be licensed as
parties under the terms of this

you distribute or publish, that in
derived from the Program or any
a whole at no charge to all third
License.

c) If the modified program normally reads commands interactively
when run, you must cause it, when started running for such
interactive use in the most ordinary way, to print or display an
announcement including an appropriate copyright notice and a
notice that there is no warranty (or else, saying that you provide
a warranty) and that users may redistribute the program under
these conditions, and telling the user how to view a copy of this
License. (Exception: if the Program itself is interactive but
does not normally print such an announcement, your work based on
the Program is not required to print an announcement.)
These requirements apply to the modified work as a whole. If
identifiable sections of that work are not derived from the Program,
and can be reasonably considered independent and separate works in
themselves, then this License, and its terms, do not apply to those
sections when you distribute them as separate works. But when you
distribute the same sections as part of a whole which is a work based
on the Program, the distribution of the whole must be on the terms of
this License, whose permissions for other licensees extend to the
entire whole, and thus to each and every part regardless of who wrote it.
Thus, it is not the intent of this section to claim rights or contest
your rights to work written entirely by you; rather, the intent is to
exercise the right to control the distribution of derivative or
collective works based on the Program.
In addition, mere aggregation of another work not based on the Program
with the Program (or with a work based on the Program) on a volume of
a storage or distribution medium does not bring the other work under
the scope of this License.
3. You may copy and distribute the Program (or a work based on it,

286

under Section 2) in object code or executable form under the terms of
Sections 1 and 2 above provided that you also do one of the following:
a) Accompany it with the complete corresponding machine-readable
source code, which must be distributed under the terms of Sections
1 and 2 above on a medium customarily used for software interchange; or,
b) Accompany it with a written offer, valid for at least three
years, to give any third party, for a charge no more than your
cost of physically performing source distribution, a complete
machine-readable copy of the corresponding source code, to be
distributed under the terms of Sections 1 and 2 above on a medium
customarily used for software interchange; or,
c) Accompany it with the information you received as to the offer
to distribute corresponding source code. (This alternative is
allowed only for noncommercial distribution and only if you
received the program in object code or executable form with such
an offer, in accord with Subsection b above.)
The source code for a work means the preferred form of the work for
making modifications to it. For an executable work, complete source
code means all the source code for all modules it contains, plus any
associated interface definition files, plus the scripts used to
control compilation and installation of the executable. However, as a
special exception, the source code distributed need not include
anything that is normally distributed (in either source or binary
form) with the major components (compiler, kernel, and so on) of the
operating system on which the executable runs, unless that component
itself accompanies the executable.
If distribution of executable or object code is made by offering
access to copy from a designated place, then offering equivalent
access to copy the source code from the same place counts as
distribution of the source code, even though third parties are not
compelled to copy the source along with the object code.
4. You may not copy, modify, sublicense, or distribute the Program
except as expressly provided under this License. Any attempt
otherwise to copy, modify, sublicense or distribute the Program is
void, and will automatically terminate your rights under this License.
However, parties who have received copies, or rights, from you under
this License will not have their licenses terminated so long as such
parties remain in full compliance.
5. You are not required to accept this License, since you have not
signed it. However, nothing else grants you permission to modify or
distribute the Program or its derivative works. These actions are

287

prohibited by law if you do not accept this License. Therefore, by
modifying or distributing the Program (or any work based on the
Program), you indicate your acceptance of this License to do so, and
all its terms and conditions for copying, distributing or modifying
the Program or works based on it.
6. Each time you redistribute the Program (or any work based on the
Program), the recipient automatically receives a license from the
original licensor to copy, distribute or modify the Program subject to
these terms and conditions. You may not impose any further
restrictions on the recipients' exercise of the rights granted herein.
You are not responsible for enforcing compliance by third parties to
this License.
7. If, as a consequence of a court judgment or allegation of patent
infringement or for any other reason (not limited to patent issues),
conditions are imposed on you (whether by court order, agreement or
otherwise) that contradict the conditions of this License, they do not
excuse you from the conditions of this License. If you cannot
distribute so as to satisfy simultaneously your obligations under this
License and any other pertinent obligations, then as a consequence you
may not distribute the Program at all. For example, if a patent
license would not permit royalty-free redistribution of the Program by
all those who receive copies directly or indirectly through you, then
the only way you could satisfy both it and this License would be to
refrain entirely from distribution of the Program.
If any portion of this section is held invalid or unenforceable under
any particular circumstance, the balance of the section is intended to
apply and the section as a whole is intended to apply in other
circumstances.
It is not the purpose of this section to induce you to infringe any
patents or other property right claims or to contest validity of any
such claims; this section has the sole purpose of protecting the
integrity of the free software distribution system, which is
implemented by public license practices. Many people have made
generous contributions to the wide range of software distributed
through that system in reliance on consistent application of that
system; it is up to the author/donor to decide if he or she is willing
to distribute software through any other system and a licensee cannot
impose that choice.
This section is intended to make thoroughly clear what is believed to
be a consequence of the rest of this License.
8. If the distribution and/or use of the Program is restricted in
certain countries either by patents or by copyrighted interfaces, the

288

original copyright holder who places the Program under this License
may add an explicit geographical distribution limitation excluding
those countries, so that distribution is permitted only in or among
countries not thus excluded. In such case, this License incorporates
the limitation as if written in the body of this License.
9. The Free Software Foundation may publish revised and/or new versions
of the General Public License from time to time. Such new versions will
be similar in spirit to the present version, but may differ in detail to
address new problems or concerns.
Each version is given a distinguishing version number. If the Program
specifies a version number of this License which applies to it and "any
later version", you have the option of following the terms and conditions
either of that version or of any later version published by the Free
Software Foundation. If the Program does not specify a version number of
this License, you may choose any version ever published by the Free Software
Foundation.
10. If you wish to incorporate parts of the Program into other free
programs whose distribution conditions are different, write to the author
to ask for permission. For software which is copyrighted by the Free
Software Foundation, write to the Free Software Foundation; we sometimes
make exceptions for this. Our decision will be guided by the two goals
of preserving the free status of all derivatives of our free software and
of promoting the sharing and reuse of software generally.
NO WARRANTY
11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN
OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS
TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE
PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
REPAIR OR CORRECTION.
12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.

289

END OF TERMS AND CONDITIONS
How to Apply These Terms to Your New Programs
If you develop a new program, and you want it to be of the greatest
possible use to the public, the best way to achieve this is to make it
free software which everyone can redistribute and change under these terms.
To do so, attach the following notices to the
to attach them to the start of each source file
convey the exclusion of warranty; and each file
the "copyright" line and a pointer to where the

program. It is safest
to most effectively
should have at least
full notice is found.

Copyright (C)
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

Also add information on how to contact you by electronic and paper mail.
If the program is interactive, make it output a short notice like this
when it starts in an interactive mode:
Gnomovision version 69, Copyright (C) year name of author
Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
This is free software, and you are welcome to redistribute it
under certain conditions; type `show c' for details.
The hypothetical commands `show w' and `show c' should show the appropriate
parts of the General Public License. Of course, the commands you use may
be called something other than `show w' and `show c'; they could even be
mouse-clicks or menu items--whatever suits your program.
You should also get your employer (if you work as a programmer) or your

290

school, if any, to sign a "copyright disclaimer" for the program, if
necessary. Here is a sample; alter the names:
Yoyodyne, Inc., hereby disclaims all copyright interest in the program
`Gnomovision' (which makes passes at compilers) written by James Hacker.
, 1 April 1989
Ty Coon, President of Vice
This General Public License does not permit incorporating your program into
proprietary programs. If your program is a subroutine library, you may
consider it more useful to permit linking proprietary applications with the
library. If this is what you want to do, use the GNU Library General
Public License instead of this License.

291

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