m0n0wall - Embedded Firewall

m0n0wall is a project aimed at creating a complete, embedded firewall software package that, when used together with an embedded PC, provides all the important features of commercial firewall boxes. The entire system configuration is stored in one single XML text file to keep things transparent. It features include NAT/PAT, IPv6 support, SNMP agent, caching DNS forwarder, VPN tunnels and lot more.