SmallWall is a complete embedded firewall software package that, when used together with an embedded PC, provides all the important features of commercial firewall boxes (including ease of use) at a fraction of the price (free software). SmallWall is based on a bare-bones version of FreeBSD, along with a web server (thttpd), PHP and a few other utilities. The entire system configuration is stored in one single XML text file to keep things transparent.