Find the HOWTO or step-by-step guide that you need right here.
The goal of WallFire is to build a very general and modular firewalling application based on netfilter or any kind of low-level framework. It will provide a multi-language API, command line and interactive console tools as well as X or HTML front-end
This document discusses how to set up a very simple firewall for Linux, to greatly increase the security of your box against outside attacks.
This is a programmers guide to IP Filter. Describes stateful properties, design issues, and brief examples.
