Additional Resources

Packet filtering and iptables are complex subjects. Additional information can be helpful in providing alternative viewpoints and methods for controlling network traffic on your system.

Installed Documentation

The iptables man page contains a comprehensive description of various commands, parameters, and other options that assist in the addition of new tables and construction of chain rules.

Useful Websites

http://netfilter.samba.org — Contains assorted information about iptables, including an FAQ addressing specific problems you may see and various helpful guides by Rusty Russell, the Linux IP firewall maintainer. The HOWTO documents here cover subjects such as basic networking concepts, 2.4 kernel packet filtering and NAT configurations, and Netfilter.
http://www.linuxnewbie.org/nhf/intel/security/iptables_basics.html —A very basic and general look at the way packets move through the Linux kernel, plus an introduction to constructing simple iptables commands.
http://securityportal.com/cover/coverstory20010122.html — An introductory look at new packet handling features in the 2.4 kernel, including stateful firewalling, defending against Denial of Service attacks and stealth scans, filtering by MAC address, and enhanced packet logging.