NetDumper

NetDumper - Network packet sniffer that dumps all packets to a file

Version: 0.22
License: Free
Operating System: Mac OS X
Homepage: www.tastycocoabytes.com
Developed by: Jens Francke

NetDumper is a free Mac OS X network packet sniffer that dumps all packets to a file. Simple and plain without the overhead of any analyzer.

Since it uses libPCAP it supports most expressions you are used to use from tcpdump.