Mastering Linux Security and Hardening - Second Edition

An overview of iptables

A common misconception is that iptables is the name of the Linux firewall. In reality, the name of the Linux firewall is netfilter, and every Linux distro has it built in. What we know is that iptables is just one of several command-line utilities that we can use to manage netfilter. It was originally introduced as a feature of Linux kernel version 2.6, so it's been around for a long time. With iptables, you do have a few advantages:

• It's been around long enough that most Linux admins already know how to use it.
• It's easy to use iptables commands in shell scripts to create your own custom firewall configuration.
• It has great flexibility in that you can use it to set up a simple port filter, a router, or a virtual ...