” Wireshark is an open source network packet analyzer. Without
any special hardware or reconfiguration, it can capture live data
going in and out over any of your box’s network interfaces:
Ethernet, WiFi, PPP, loopback, even USB. Typically it’s used as a
forensics tool for troubleshooting network problems like
congestion, high latency, or protocol errors — but you don’t
want to wait until your network is in trouble to learn how to use
it. This weekend, why not take a look at your network traffic, and
learn how to use Wireshark to your advantage?“Wireshark is a GTK+ application, although the project also
includes a console-based front end named TShark that features most
of the functionality found in the GUI version. Considering its
reputation as a useful administration tool, you will probably find
it in your distribution’s package repositories. If not, you can
download packages for several distributions on wireshark.org, along
with the source. The current release is 1.4.1. Mac OS X and Windows
binaries are available as well, which you may need to analyze
machines running those operating systems (more on that later).”