Smoothwall is a family of Internet security products, designed to defend your users and your network from external attacks. Smoothwall Express is based on the 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.