A full packet capturing, indexing, and database system
VoIP SIP and SKINNY quality analyzer and packet / audio recording tool
An open source real-time network topology and protocols analyzer
Package xdp allows one to use XDP sockets
Xplico is a Network Forensic Analysis Tool (NFAT)
A java packet sniffer and forger that wraps pcap libs.
...has moved to packetpeeper.org