Justniffer

Chaosreader

An any-snarf program that processes application protocols (HTTP/FTP/...) from tcpdump or snoop files and stores session and file data

pcapfex

'Packet Capture Forensic Evidence eXtractor' is a tool that finds and extracts files from packet capture files

NetworkMiner

NetworkMiner is a Network Forensic Analysis Tool (NFAT) for Windows (but also works in Linux / Mac OS X / FreeBSD). NetworkMiner can be used as a passive network sniffer/packet capturing tool in order to detect operating systems, sessions, hostnames, open ports etc. without putting any traffic on the network. NetworkMiner can also parse PCAP files for off-line analysis and to regenerate/ reassemble transmitted files and certificates from PCAP files

Snort

Snort is a free and open source network intrusion prevention system (NIPS) and network intrusion detection system (NIDS)created by Martin Roesch in 1998. Snort is now developed by Sourcefire, of which Roesch is the founder and CTO. In 2009, Snort entered InfoWorld's Open Source Hall of Fame as one of the "greatest [pieces of] open source software of all time"