Modern tcpdump

   One of the most important tools needed to be sure your running IPSEC correctly is tcpdump, which lets you look at whats actually happening on the wire. To get a tcpdump that knows about IPSEC packets and how to print out network traffic in ASCII we suggest getting a new copy of tcpdump from http://www.tcpdump.org.

Packet Examiner

   For a nice GUI when looking at IP on the wire, we suggest using Ethereal.