TcpWatch is a great program to view what goes on during a transaction.
You can find it at http://www.zope.org/Members/hathawsh/tcpwatch

You run it as::

    $ python tcpwatch.py 8080 myserver.com 80</code>

And when you connect to localhost:8080, you'll get pages from
myserver.com:80 -- except that everything that goes back and forth
will be tracked through a nice Tk interface.

-- IanBicking_ - 15 Nov 2001