Iptables is a module that provides the Linux operating system functions of firewall, NAT and logging of data traveling over a computer network.

iptables is the name of the tool that allows you to create firewall rules and NATs. While technically iptables is merely a tool that controls the netfilter module, the name "iptables" is often used as a reference to the full functionality of netfilter. Iptables is part of all modern Linux distributions.