Troubleshooting Linux® Firewalls

Chapter 12. NAT (Network Address Translation) and IP Forwarding

By far perhaps the most common use of Linux firewalls these days are in SOHO (Small Office/Home Office) environments. NAT-ing, or setting up a firewall to perform Network Address Translation (NAT) services, is simply a method of translating one address space to another—or to be more specific in terms of SOHO users, a method of sharing a single network connection amongst multiple machines. NAT-ing is probably one of the most common uses of a firewall.

For more advanced installations, we can use NAT to create “DMZ” networks (short for De-Militarized Zones), which are networks that sit off to the “side” of the firewall so to speak. DMZs are dedicated to some specific task such as hosting ...