iptables is built on top of netfilter, the packet alteration framework for Linux 2.4.x and 2.6.x. It is a major rewrite of its predecessor ipchains, and is used to control packet filtering, Network Address Translation (masquerading, portforwarding, transparent proxying), and special effects such as packet mangling.
4468ce7e1d68349a8e30f26110eb7969dbfdbf497d6c53758883123b3f2d6f6e