pfSense

pfSense is a free, open source customized distribution of FreeBSD tailored for use as a firewall and router. In addition to being a powerful, flexible firewalling and routing platform, it includes a long list of related features and a package system allowing further expandability without adding bloat and potential security vulnerabilities to the base distribution. Features include VPN, Wireless Access Point, Traffic Shaping and real time monitoring of traffic.

The link address is: http://www.pfsense.com/