Wireshark

The second life of the packet analysis tool formerly known as Ethereal, which reached 1.0 on Mar 31st, 2008

Basic vim folding for text dumps (basically fold on any line beginning with a space, one level only):

:set foldexpr=getline(v:lnum)[0]==\"\ \"
:set foldmethod=expr

Under Leopard, Wireshark can be built from MacPorts, and it should be done using:

$ sudo port install wireshark +ipv6

This avoids, among other things, a couple of bugs that may cause the application to crash. (setting X11 to thousands of colors also helps).