Free UTM appliance: firewall, VPN, WAF and antivirus in one ISO.
Next Generation Open Source Firewall
Tranalyzer flow generator packet analyzer moved to: tranalyzer.com
Web security protection system based on openresty
Snare Enterprise: bit.ly/Snare-Trial
Xplico is a Network Forensic Analysis Tool (NFAT)
PCAP from another point of view
Analizes PCAP files and gives statistics about IP packets.
Open Source SIEM
Free-SA is report generating tool for web, proxy and mail log files
Online Multi-Engine Antivirus Scanner
Passive Proxy Daemon sniffs packets and creates squid proxy logs