wireshark/docbook/eug_src/EUG_chapter_customize.xml

785 lines
27 KiB
XML

<!-- EUG Chapter Customizing -->
<!-- $Id$ -->
<chapter id="ChapterCustomize">
<title>Customizing Ethereal</title>
<section id="ChCustIntroduction"><title>Introduction</title>
<para>
Ethereal's default behaviour will usually suit your needs pretty well.
However, as you become more familiar with Ethereal, it can be customized
in various ways to suit your needs even better. In this chapter we explore:
<itemizedlist>
<listitem>
<para>
How to start Ethereal with command line parameters
</para>
</listitem>
<listitem>
<para>
How to colorize the packet list
</para>
</listitem>
<listitem>
<para>
How to control protocol dissection
</para>
</listitem>
<listitem>
<para>
How to use the various preference settings
</para>
</listitem>
</itemizedlist>
</para>
</section>
<section id="ChCustCommandLine"><title>Start Ethereal from the command line</title>
<para>
You can start <application>Ethereal</application> 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.
</para>
<para>
<application>Ethereal</application> supports a large number of
command line parameters. To see what they are, simply enter the
command <command> ethereal -h</command> and the help information
shown in <xref linkend="ChCustEx1"/> (or something similar) should be
printed.
<example id="ChCustEx1">
<title>Help information available from Ethereal</title>
<programlisting>
This is GNU ethereal 0.10.11
(C) 1998-2005 Gerald Combs &lt;gerald@ethereal.com>
Compiled with GTK+ 2.4.14, with GLib 2.4.7, with WinPcap (version unknown),
with libz 1.2.2, with libpcre 4.4, with Net-SNMP 5.1.2, with ADNS.
Running with WinPcap version 3.1 beta4 (packet.dll version 3, 1, 0, 24), based o
n libpcap version 0.8.3 on Windows XP Service Pack 1, build 2600.
ethereal [ -vh ] [ -klLnpQS ] [ -a &lt;capture autostop condition> ] ...
[ -b &lt;capture ring buffer option> ] ...] [ -B capture buffer size (Win32 only) ]
[ -c &lt;capture packet count> ] [ -f &lt;capture filter> ]
[ -g &lt;packet number> ]
[ -i &lt;capture interface> ] [ -m &lt;font> ] [ -N &lt;name resolving flags> ]
[ -o &lt;preference/recent setting> ] ...
[ -r &lt;infile> ] [ -R &lt;read (display) filter> ] [ -s &lt;capture snaplen> ]
[ -t &lt;time stamp format> ]
[ -w &lt;savefile> ] [ -y &lt;capture link type> ] [ -z &lt;statistics> ]
[ &lt;infile> ]
</programlisting>
</example>
We will examine each of the command line options in turn.
</para>
<para>
The first thing to notice is that issuing the command
<command>ethereal</command> by itself will bring up
<application>Ethereal</application>.
However, you can include as many of the command line parameters as
you like. Their meanings are as follows ( in alphabetical order ):
XXX - is the alphabetical order a good choice? Maybe better task based?
<variablelist>
<varlistentry><term><command>-a &lt;capture autostop condition></command></term>
<listitem>
<para>
Specify a criterion that specifies when Ethereal is to stop writing
to a capture file. The criterion is of the form test:value, where test
is one of:
<variablelist>
<varlistentry><term><command>duration</command>:value</term>
<listitem><para>
Stop writing to a capture file after value of seconds have elapsed.
</para></listitem>
</varlistentry>
<varlistentry><term><command>filesize</command>:value</term>
<listitem><para>
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, Ethereal will
stop writing to the current capture file and switch to the next
one if filesize is reached.
</para></listitem>
</varlistentry>
<varlistentry><term><command>files</command>:value</term>
<listitem><para>
Stop writing to capture files after value number of files were
written.
</para></listitem>
</varlistentry>
</variablelist>
</para>
</listitem>
</varlistentry>
<varlistentry><term><command>-b &lt;capture ring buffer option></command></term>
<listitem>
<para>
If a maximum capture file size was specified, cause Ethereal to run
in "ring buffer" mode, with the specified number of files. In "ring
buffer" mode, Ethereal will write to several capture files. Their
name is based on the number of the file and on the creation date and
time.
</para>
<para>
When the first capture file fills up, Ethereal will switch to writing
to the next file, until it fills up the last file, at which point
it'll discard the data in the first file (unless 0 is specified, in
which case, the number of files is unlimited) and start writing to
that file and so on.
</para>
<para>
If the optional duration is specified, Ethereal will switch also to
the next file when the specified number of seconds has elapsed even
if the current file is not completely fills up.
</para>
<para>
<variablelist>
<varlistentry><term><command>duration</command>:value</term>
<listitem><para>
Switch to the next file after value seconds have elapsed, even
if the current file is not completely filled up.
</para></listitem>
</varlistentry>
<varlistentry><term><command>filesize</command>:value</term>
<listitem><para>
Switch to the next file after it reaches a size of value kilobytes
(where a kilobyte is 1000 bytes, not 1024 bytes).
</para></listitem>
</varlistentry>
<varlistentry><term><command>files</command>:value</term>
<listitem><para>
Begin again with the first file after value number of files were
written (form a ring buffer).
</para></listitem>
</varlistentry>
</variablelist>
</para>
</listitem>
</varlistentry>
<varlistentry><term><command>-B &lt;capture buffer size (Win32 only)></command></term>
<listitem>
<para>
Win32 only: set capture buffer size (in MB, default is 1MB). This
is used by the 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.
</para>
</listitem>
</varlistentry>
<varlistentry><term><command>-c &lt;capture packet count></command></term>
<listitem>
<para>
This option specifies the maximum number of packets to capture
when capturing live data. It would be used in conjunction
with the <command>-k</command> option.
</para>
</listitem>
</varlistentry>
<varlistentry><term><command>-f &lt;capture filter></command></term>
<listitem>
<para>
This option sets the initial capture filter expression to
be used when capturing packets.
</para>
</listitem>
</varlistentry>
<varlistentry><term><command>-g &lt;packet number></command></term>
<listitem>
<para>
After reading in a capture file using the -r flag, go to the given
packet number.
</para>
</listitem>
</varlistentry>
<varlistentry><term><command>-h</command></term>
<listitem>
<para>
The <command>-h</command> option requests Ethereal to print
its version and usage instructions (as shown above) and exit.
</para>
</listitem>
</varlistentry>
<varlistentry><term><command>-i &lt;capture interface></command></term>
<listitem>
<para>
The <command>-i</command> option allows you to specify,
from the command line, which interface packet capture should
occur on if capturing packets.
</para>
<para>
An example would be: <command>ethereal -i eth0</command>.
</para>
<para>
To get a listing of all the interfaces you can capture on,
use the command <command>ifconfig -a</command> or
<command>netstat -i</command>. Unfortunately, some versions of
UNIX do not support <command>ifconfig -a</command>, so you
will have to use <command>netstat -i</command> in these cases.
</para>
</listitem>
</varlistentry>
<varlistentry><term><command>-k</command></term>
<listitem>
<para>
The <command>-k</command> option specifies that Ethereal
should start capturing packets immediately. This option
requires the use of the <command>-i</command> parameter to
specify the interface that packet capture will occur from.
</para>
</listitem>
</varlistentry>
<varlistentry><term><command>-l</command></term>
<listitem>
<para>
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 <command>-S</command>
flag).
</para>
</listitem>
</varlistentry>
<varlistentry><term><command>-L</command></term>
<listitem>
<para>
List the data link types supported by the interface and exit.
</para>
</listitem>
</varlistentry>
<varlistentry><term><command>-m &lt;font></command></term>
<listitem>
<para>
This option sets the name of the font used for most text
displayed by Ethereal. XXX - add an example!
</para>
</listitem>
</varlistentry>
<varlistentry><term><command>-n</command></term>
<listitem>
<para>
Disable network object name resolution (such as hostname, TCP and UDP
port names).
</para>
</listitem>
</varlistentry>
<varlistentry><term><command>-N &lt;name resolving flags></command></term>
<listitem>
<para>
Turns on name resolving for particular types of addresses
and port numbers; the argument is a string that may contain
the letters <command>m</command> to enable MAC address
resolution, <command>n</command> to enable network address
resolution, and <command>t</command> to enable transport-layer
port number resolution. This overrides <command>-n</command>
if both <command>-N</command> and <command>-n</command> are
present. The letter C enables concurrent (asynchronous) DNS lookups.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><command>-o &lt;preference/recent settings&gt;</command></term>
<listitem>
<para>
Sets a preference or recent value, overriding the default value and
any value read from a preference/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 preference/recent file), and value is the value
to which it should be set. Multiple instances of
<command>-o &lt;preference settings&gt; </command> can be
given on a single command line.
</para>
<para>An example of setting a single preference would be: </para>
<para>
<command>
ethereal -o mgcp.display_dissect_tree:TRUE
</command>
</para>
<para>
An example of setting multiple preferences would be:
</para>
<para>
<command>
ethereal -o mgcp.display_dissect_tree:TRUE -o mgcp.udp.callagent_port:2627
</command>
</para>
<tip><title>Tip!</title>
<para>
You can get a list of all available preference strings from the
preferences file, see <xref linkend="AppFiles"/>.
</para>
</tip>
</listitem>
</varlistentry>
<varlistentry><term><command>-p</command></term>
<listitem>
<para>
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 Ethereal is running, broadcast traffic, and
multicast traffic to addresses received by that machine.
</para>
</listitem>
</varlistentry>
<varlistentry><term><command>-Q</command></term>
<listitem>
<para>
This option forces Ethereal to exit when capturing is
complete. It can be used with the <command>-c</command> option.
It must be used in conjunction with the
<command>-i</command> and <command>-w</command> options.
</para>
</listitem>
</varlistentry>
<varlistentry><term><command>-r &lt;infile></command></term>
<listitem>
<para>
This option provides the name of a capture file for Ethereal
to read and display. This capture file can be in one of the
formats Ethereal understands.
</para>
</listitem>
</varlistentry>
<varlistentry><term><command>-R &lt;read (display) filter></command></term>
<listitem>
<para>
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
<xref linkend="ChWorkDisplayFilterSection"/>. Packets not
matching the filter are discarded.
</para>
</listitem>
</varlistentry>
<varlistentry><term><command>-s &lt;capture snaplen></command></term>
<listitem>
<para>
This option specifies the snapshot length to use when
capturing packets. Ethereal will only capture
<command>&lt;snaplen></command> bytes of data for each packet.
</para>
</listitem>
</varlistentry>
<varlistentry><term><command>-S</command></term>
<listitem>
<para>
This option specifies that Ethereal 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.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><command>-t &lt;time stamp format></command></term>
<listitem>
<para>
This option sets the format of packet timestamps that are
displayed in the packet list window. The format can be one of:
<itemizedlist>
<listitem>
<para>
<command>r</command> relative, which specifies timestamps are
displayed relative to the first packet captured.
</para>
</listitem>
<listitem>
<para>
<command>a</command> absolute, which specifies that actual times
be displayed for all packets.
</para>
</listitem>
<listitem>
<para>
<command>ad</command> absolute with date, which specifies that
actual dates and times be displayed for all packets.
</para>
</listitem>
<listitem>
<para>
<command>d</command> delta, which specifies that timestamps
are relative to the previous packet.
</para>
</listitem>
</itemizedlist>
</para>
</listitem>
</varlistentry>
<varlistentry><term><command>-v</command></term>
<listitem>
<para>
The <command>-v</command> option requests
Ethereal to print out its version information and exit.
</para>
</listitem>
</varlistentry>
<varlistentry><term><command>-w &lt;savefile></command></term>
<listitem>
<para>
This option sets the name of the <command>savefile</command>
to be used when saving a capture file.
</para>
</listitem>
</varlistentry>
<varlistentry><term><command>-y &lt;capture link type></command></term>
<listitem>
<para>
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.
</para>
</listitem>
</varlistentry>
<varlistentry><term><command>-z &lt;statistics-string></command></term>
<listitem>
<para>
Get Ethereal to collect various types of statistics and display the
result in a window that updates in semi-real time.
XXX - add more details here!
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</section>
<section id="ChCustColorizationSection"><title>Packet colorization</title>
<para>
A very useful mechanism available in Ethereal is packet colorization.
You can set-up Ethereal so that it will colorize packets according to a
filter. This allows you to emphasize the packets you are usually
interested in.
</para>
<tip>
<title>Tip!</title>
<para>
You will find a lot of Coloring Rule examples at the <command>Ethereal
Wiki Coloring Rules page</command> at <ulink
url="&EtherealWikiColoringRulesPage;">&EtherealWikiColoringRulesPage;</ulink>.
</para>
</tip>
<para>
To colorize packets, select the Coloring Rules... menu item from
the View menu, Ethereal will pop up the "Coloring Rules"
dialog box as shown in <xref linkend="ChCustColoringRulesDialog"/>.
</para>
<figure id="ChCustColoringRulesDialog">
<title>The "Coloring Rules" dialog box</title>
<graphic entityref="EtherealColoringRulesDialog" format="PNG"/>
</figure>
<para>
Once the Coloring Rules dialog box is up, there are a number
of buttons you can use, depending on whether or not you have any
color filters installed already.
</para>
<note><title>Note!</title>
<para>
You will need to carefully select the order the coloring rules are listed
(and thus applied) as they are applied in order from top to bottom.
So, more specific rules need to be listed before more general rules.
For example, if you have a color rule for UDP before the one for DNS,
the color rule for DNS will never be applied (as DNS uses UDP, so the
UDP rule will be matching first).
</para>
</note>
<para>
If this is the first time you have used Coloring Rules, click on the New
button which will bring up the Edit color filter dialog box as shown in
<xref linkend="ChCustEditColorDialog"/>.
</para>
<figure id="ChCustEditColorDialog">
<title>The "Edit Color Filter" dialog box</title>
<graphic entityref="EtherealEditColorDialog" format="PNG"/>
</figure>
<para>
In the Edit Color dialog box, simply enter a name for the color filter,
and enter a filter string in the Filter text field.
<xref linkend="ChCustEditColorDialog"/> shows the values
<command>arp</command> and <command>arp</command> which means that
the name of the color filter is <command>arp</command> and the filter
will select protocols of type <command>arp</command>. Once you have
entered these values, you can choose a foreground and background
color for packets that match the filter expression. Click on
<command>Foreground color...</command> or
<command>Background color...</command> to achieve this and
Ethereal will pop up the Choose foreground/background color for
protocol dialog box as shown in
<xref linkend="ChCustChooseColorDialog"/>.
</para>
<figure id="ChCustChooseColorDialog">
<title>The "Choose color" dialog box</title>
<graphic entityref="EtherealChooseColorDialog" format="PNG"/>
</figure>
<para>
Select the color you desire for the selected packets and click on OK.
</para>
<note>
<title>Note!</title>
<para>
You must select a color in the colorbar next to the colorwheel to
load values into the RGB values. Alternatively, you can set the
values to select the color you want.
</para>
</note>
<para>
<xref linkend="ChCustColorFilterMany"/> shows an example of several color
filters being used in Ethereal. You may not like the color choices,
however, feel free to choose your own.
</para>
<figure id="ChCustColorFilterMany">
<title>Using color filters with Ethereal</title>
<graphic entityref="EtherealThreePane1" format="PNG"/>
</figure>
</section>
<section id="ChCustProtocolDissectionSection">
<title>Control Protocol dissection</title>
<para>
The user can control how protocols are dissected.
</para>
<para>
Each protocol has its own dissector, so dissecting a complete packet will
typically involve several dissectors. As Ethereal 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, Ethereal 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.
</para>
<para>
There are two ways to control the relations between protocol
dissectors: disable a protocol dissector completely or temporarily
divert the way Ethereal calls the dissectors.
</para>
<section id="ChAdvEnabledProtocols"><title>The "Enabled Protocols" dialog
box</title>
<para>
The Enabled Protocols dialog box lets you enable or
disable specific protocols, all protocols are enabled by default.
When a protocol is disabled, Ethereal stops processing a packet
whenever that protocol is encountered.
</para>
<note><title>Note!</title>
<para>
Disabling a protocol will prevent information about higher-layer
protocols from being displayed. For example,
suppose you disabled the IP protocol and selected
a 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.
</para>
</note>
<figure id="ChAdvEnabledProtocolsFig">
<title>The "Enabled Protocols" dialog box</title>
<graphic entityref="EtherealEnabledProtocols" format="PNG"/>
</figure>
<para>
To disable or enable a protocol, simply click on it using the
mouse or press the space bar when the protocol is highlighted.
</para>
<warning><title>Warning!</title>
<para>
You have to use the Save button to save your settings. The OK or Apply
buttons will not save your changes permanently, so they will be lost
when Ethereal is closed.
</para>
</warning>
<para>
You can choose from the following actions:
<orderedlist>
<listitem>
<para>
<command>Enable All</command> Enable all protocols in the list.
</para>
</listitem>
<listitem>
<para>
<command>Disable All</command> Disable all protocols in the list.
</para>
</listitem>
<listitem>
<para>
<command>Invert</command> Toggle the state of all protocols in the
list.
</para>
</listitem>
<listitem>
<para>
<command>OK</command> Apply the changes and close the dialog box.
</para>
</listitem>
<listitem>
<para>
<command>Apply</command> Apply the changes and keep the dialog box
open.
</para>
</listitem>
<listitem>
<para>
<command>Save</command> Save the settings to the disabled_protos, see
<xref linkend="AppFiles"/> for details.
</para>
</listitem>
<listitem>
<para>
<command>Cancel</command> Cancel the changes and close the dialog box.
</para>
</listitem>
</orderedlist>
</para>
</section>
<section id="ChAdvDecodeAs"><title>User Specified Decodes</title>
<para>
The "Decode As" functionality let you temporarily divert specific
protocol dissections. This might be useful for example, if you do some
uncommon experiments on your network.
</para>
<para>
<figure id="ChAdvDecodeAsFig">
<title>The "Decode As" dialog box</title>
<graphic scale="100" entityref="EtherealDecodeAs" format="PNG"/>
</figure>
The content of this dialog box depends on the selected packet when it
was opened.
<warning><title>Warning!</title>
<para>
The user specified decodes can not be saved. If you quit Ethereal,
these settings will be lost.
</para>
</warning>
<orderedlist>
<listitem>
<para>
<command>Decode</command> Decode packets the selected way.
</para>
</listitem>
<listitem>
<para>
<command>Do not decode</command> Do not decode packets the selected
way.
</para>
</listitem>
<listitem>
<para>
<command>Link/Network/Transport</command> 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 was opened.
</para>
</listitem>
<listitem>
<para>
<command>Show Current</command> Open a dialog box showing the
current list of user specified decodes.
</para>
</listitem>
<listitem>
<para>
<command>OK</command> Apply the currently selected decode and close
the dialog box.
</para>
</listitem>
<listitem>
<para>
<command>Apply</command> Apply the currently selected decode and keep
the dialog box open.
</para>
</listitem>
<listitem>
<para>
<command>Cancel</command> Cancel the changes and close the dialog box.
</para>
</listitem>
</orderedlist>
</para>
</section>
<section id="ChAdvDecodeAsShow"><title>Show User Specified Decodes</title>
<para>
This dialog box shows the currently active user specified decodes.
<figure id="ChAdvDecodeAsShowFig">
<title>The "Decode As: Show" dialog box</title>
<graphic entityref="EtherealDecodeAsShow" format="PNG"/>
</figure>
<orderedlist>
<listitem>
<para>
<command>OK</command> Close this dialog box.
</para>
</listitem>
<listitem>
<para>
<command>Clear</command> Removes all user specified decodes.
</para>
</listitem>
</orderedlist>
</para>
</section>
</section>
<section id="ChCustPreferencesSection"><title>Preferences</title>
<para>
There are a number of preferences you can set. Simply
select the Preferences... menu item from the Edit menu, and Ethereal
will pop up the Preferences dialog box as shown in
<xref linkend="ChCustGUIPrefPage"/>, with the "User Interface" page as
default. On the left side is a tree where you can select the page to be
shown.
<note><title>Note!</title>
<para>
Preference settings are added frequently. For a recent explanation of
the preference pages and their settings have a look at the
<command>Ethereal Wiki Preferences page</command> at <ulink
url="&EtherealWikiPreferencesPage;">&EtherealWikiPreferencesPage;</ulink>.
</para>
</note>
<warning>
<title>Warning!</title>
<para>
The OK or Apply button will not save the preference settings,
you'll have to save the settings by clicking the Save button.
</para>
</warning>
<itemizedlist>
<listitem>
<para>
The <command>OK</command> button will apply the preferences
settings and close the dialog.
</para>
</listitem>
<listitem>
<para>
The <command>Apply</command> button will apply the preferences
settings and keep the dialog open.
</para>
</listitem>
<listitem>
<para>
The <command>Save</command> button will apply the preferences
settings, save the settings on the harddisk and keep the dialog open.
</para>
</listitem>
<listitem>
<para>
The <command>Cancel</command> button will restore all preferences
settings to the last saved state.
</para>
</listitem>
</itemizedlist>
</para>
<figure id="ChCustGUIPrefPage">
<title>The preferences dialog box</title>
<graphic entityref="EtherealGUIPreferences" format="PNG"/>
</figure>
</section>
</chapter>
<!-- End of EUG Chapter Customizing -->