General Information
-------------------

Wireshark is a network traffic analyzer, or "sniffer", for Unix and
Unix-like operating systems.  It uses Qt, a graphical user interface
library, and libpcap, a packet capture and filtering library.

The Wireshark distribution also comes with TShark, which is a
line-oriented sniffer (similar to Sun's snoop, or tcpdump) that uses the
same dissection, capture-file reading and writing, and packet filtering
code as Wireshark, and with editcap, which is a program to read capture
files and write the packets from that capture file, possibly in a
different capture file format, and with some packets possibly removed
from the capture.

The official home of Wireshark is

    https://www.wireshark.org

The latest distribution can be found in the subdirectory

    https://www.wireshark.org/download


Installation
------------

The Wireshark project builds and tests regularly on the following platforms:

  - Linux (Ubuntu)
  - Microsoft Windows
  - macOS / OS X

Official installation packages are available for Microsoft Windows and
macOS.

It is available as either a standard or add-on package for many popular
operating sytems and Linux distributions including Debian, Ubuntu, Fedora,
CentOS, RHEL, Arch, Gentoo, openSUSE, FreeBSD, DragonFly BSD, NetBSD, and
OpenBSD.

Additionaly it is available through many third-party packaging systems
such as pkgsrc, OpenCSW, Homebrew, and MacPorts.

It should run on other Unix-ish systems without too much trouble.

In some cases the current version of Wireshark might not support your
operating system. This is the case for Windows XP, which is supported by
Wireshark 1.10 and earlier. In other cases the standard package for
Wireshark might simply be old. This is the case for Solaris and HP-UX.

NOTE: The Makefile depends on GNU "make"; it doesn't appear to
work with the "make" that comes with Solaris 7 nor the BSD "make".

Both Perl and Python are needed, the former for building the man pages.

If you decide to modify the yacc grammar or lex scanner, then
you need "flex" - it cannot be built with vanilla "lex" -
and either "bison" or the Berkeley "yacc". Your flex
version must be 2.5.1 or greater. Check this with 'flex -V'.

You must therefore install Perl, Python, GNU "make", "flex", and either "bison"
or Berkeley "yacc" on systems that lack them.

Full installation instructions can be found in the INSTALL file and in the
Developer's Guide at https://www.wireshark.org/docs/wsdg_html_chunked/

See also the appropriate README.<OS> files for OS-specific installation
instructions.

Usage
-----

In order to capture packets from the network, you need to make the
dumpcap program set-UID to root, or you need to have access to the
appropriate entry under /dev if your system is so inclined (BSD-derived
systems, and systems such as Solaris and HP-UX that support DLPI,
typically fall into this category).  Although it might be tempting to
make the Wireshark and TShark executables setuid root, or to run them as
root please don't.  The capture process has been isolated in dumpcap;
this simple program is less likely to contain security holes, and thus
safer to run as root.

Please consult the man page for a description of each command-line
option and interface feature.


Multiple File Types
-------------------

The wiretap library is a packet-capture library currently under
development parallel to wireshark.  In the future it is hoped that
wiretap will have more features than libpcap, but wiretap is still in
its infancy. However, wiretap is used in wireshark for its ability
to read multiple file types.  See the Wireshark man page or the
Wireshark User's Guide for a list of supported file formats.

In addition, it can read gzipped versions of any of those files
automatically, if you have the zlib library available when compiling
Wireshark. Wireshark needs a modern version of zlib to be able to use
zlib to read gzipped files; version 1.1.3 is known to work.  Versions
prior to 1.0.9 are missing some functions that Wireshark needs and won't
work.  "./configure" should detect if you have the proper zlib version
available and, if you don't, should disable zlib support. You can always
use "./configure --disable-zlib" to explicitly disable zlib support.

Although Wireshark can read AIX iptrace files, the documentation on
AIX's iptrace packet-trace command is sparse.  The 'iptrace' command
starts a daemon which you must kill in order to stop the trace. Through
experimentation it appears that sending a HUP signal to that iptrace
daemon causes a graceful shutdown and a complete packet is written
to the trace file. If a partial packet is saved at the end, Wireshark
will complain when reading that file, but you will be able to read all
other packets.  If this occurs, please let the Wireshark developers know
at wireshark-dev@wireshark.org, and be sure to send us a copy of that trace
file if it's small and contains non-sensitive data.

Support for Lucent/Ascend products is limited to the debug trace output
generated by the MAX and Pipline series of products.  Wireshark can read
the output of the "wandsession" "wandisplay", "wannext", and "wdd"
commands.

Wireshark can also read dump trace output from the Toshiba "Compact Router"
line of ISDN routers (TR-600 and TR-650). You can telnet to the router
and start a dump session with "snoop dump".

CoSine L2 debug output can also be read by Wireshark. To get the L2
debug output, get in the diags mode first and then use
"create-pkt-log-profile" and "apply-pkt-log-profile" commands under
layer-2 category. For more detail how to use these commands, you
should examine the help command by "layer-2 create ?" or "layer-2 apply ?".

To use the Lucent/Ascend, Toshiba and CoSine traces with Wireshark, you must
capture the trace output to a file on disk.  The trace is happening inside
the router and the router has no way of saving the trace to a file for you.
An easy way of doing this under Unix is to run "telnet <ascend> | tee <outfile>".
Or, if your system has the "script" command installed, you can save
a shell session, including telnet to a file. For example, to a file named
tracefile.out:

----
$ script tracefile.out
Script started on <date/time>
$ telnet router
..... do your trace, then exit from the router's telnet session.
$ exit
Script done on <date/time>
----


Name Resolution
---------------

Wireshark will attempt to use reverse name resolution capabilities
when decoding IPv4 and IPv6 packets.

If you want to turn off name resolution while using Wireshark, start
Wireshark with the "-n" option to turn off all name resolution (including
resolution of MAC addresses and TCP/UDP/SMTP port numbers to names), or
with the "-N mt" option to turn off name resolution for all
network-layer addresses (IPv4, IPv6, IPX).

You can make that the default setting by opening the Preferences dialog
box using the Preferences item in the Edit menu, selecting "Name
resolution", turning off the appropriate name resolution options,
clicking "Save", and clicking "OK".


SNMP
----

Wireshark can do some basic decoding of SNMP packets; it can also use
the libsmi library to do more sophisticated decoding, by reading MIB
files and using the information in those files to display OIDs and
variable binding values in a friendlier fashion.  The configure script
will automatically determine whether you have the libsmi library on
your system.  If you have the libsmi library but _do not_ want to have
Wireshark use it, you can run configure with the "--without-libsmi"
option.

How to Report a Bug
-------------------

Wireshark is under constant development, so it is possible that you will
encounter a bug while using it. Please report bugs at https://bugs.wireshark.org.
Be sure you enter into the bug:

1. The complete build information from the "About Wireshark"
   item in the Help menu or the output of "wireshark -v" for
   Wireshark bugs and the output of "tshark -v" for TShark bugs;

2. If the bug happened on Linux, the Linux distribution you were
   using, and the version of that distribution;

3. The command you used to invoke Wireshark, if you ran
   Wireshark from the command line, or TShark, if you ran
   TShark, and the sequence of operations you performed that
   caused the bug to appear.

If the bug is produced by a particular trace file, please be sure to
attach to the bug a trace file along with your bug description.  If the
trace file contains sensitive information (e.g., passwords), then please
do not send it.

If Wireshark died on you with a 'segmentation violation', 'bus error',
'abort', or other error that produces a UNIX core dump file, you can
help the developers a lot if you have a debugger installed.  A stack
trace can be obtained by using your debugger ('gdb' in this example),
the wireshark binary, and the resulting core file.  Here's an example of
how to use the gdb command 'backtrace' to do so.

----
$ gdb wireshark core
(gdb) backtrace
..... prints the stack trace
(gdb) quit
$
----

The core dump file may be named "wireshark.core" rather than "core" on
some platforms (e.g., BSD systems).  If you got a core dump with
TShark rather than Wireshark, use "tshark" as the first argument to
the debugger; the core dump may be named "tshark.core".

Disclaimer
----------

There is no warranty, expressed or implied, associated with this product.
Use at your own risk.


Gerald Combs <gerald@wireshark.org>

Gilbert Ramirez <gram@alumni.rice.edu>

Guy Harris <guy@alum.mit.edu>