Teaches the basics of firewall systems and give you some detail on setting up both a filtering and proxy firewall on a Linux based PC, by Mark Grennan.
HOWTOs describe in detail a certain aspect of configuring or using Linux. Site has information about the HOWTOs and using them, and an annotated index.
The goal of the Linux IPv6 HOWTO is to answer both basic and advanced questions about IPv6 on the Linux operating system. This HOWTO will provide the reader with enough information to install, configure, and use IPv6 applications on Linux machines.