LibPcap

Analysis

• TcpDump - sniff network traffic
• Ethereal - high powered gui packet analysis tool, with command line interface
• TcpFlow - reconstructs the data streams and stores each flow in a separate file
• TrafShow - display data rates per connection
• TcpTrace - connection level statistics, graphs, and more
• TcpStat - plot stats about captured tcp dumps
• NetDude - tcp trace viewer and editor
• ChaosReader - trace sessions and fetch application data, generates html reports
• UnixGeekTools - other great tools for unix geeks

looks interesting

• http://www.isi.edu/nsnam/nam/
• http://etherape.sourceforge.net/
• http://www.ipv4.it/cold/
• http://www.stearns.org/doc/pcap-apps.html

Other tools to check out

• Tstat - a passive sniffer able to provide several insight on the traffic patterns at both the the network and transport levels. RRDTool enabled.
• ttt - real-time capable graphical traffic monitoring - freebsd. link. requires blt
• Net::Packet::Dumper - perl mod for parsing pcap data

Other

• UnixGeekTools - other great tools for unix geeks