SmoothWall Express
SmoothWall Express is an open source firewall distribution based on the GNU/Linux operating system. Linux is the ideal choice for security systems; it is well proven, secure, highly configurable and freely††† available as open source code.
SmoothWall includes a hardened subset of the GNU/Linux operating system, so there is no separate OS to install. Designed for ease of use, SmoothWall is configured via a web-based GUI, and requires absolutely no knowledge of Linux to install or use.
SmoothWall Express is intended for use by anyone from a home user to a systems administrator. It can run on almost any PC from a 486 upwards, which becomes a dedicated firewall appliance (the SmoothWall box). Apart from the PC, all that is required is an Internet connection and some simple networking equipment to connect the SmoothWall firewall to the rest of your local, private network.
††† Free as in beer, libre, freedom. There is a lengthier explanation of "free software" on the GNU website
About SmoothWall Project
Download SmoothWall
SmoothWall @ SourceForge