Summary

In this chapter, you learned about IP forwarding, as well as masquerading and packet filtering. You then used Ipchains and Iptables to create firewall rules. The Iptables package supports packet masquerading and filtering functionality as found in the 2.3 kernel and later. This functionality is known as netfilter. Therefore, in order to use Iptables, you must recompile the kernel so that netfilter is installed, and you must install the Iptables package.

This chapter also showed you how to enable logging and ToS bits on network traffic, ands how to save, edit, and restore Ipchains and Iptables entries. You were provided with practical advice concerning commands to take, and saw how GUI and automated applications have been created to help build firewalls.

With this information, you now have all of the tools necessary to begin creating your own firewall using either Ipchains or Iptables.