"James Turnbull: Netfilter is a framework that hooks into the network stack to allow the manipulation and processing of network packets. It consists of two major components. The first component, netfilter, provides the hooks into the network stack to allow actions to be performed on the packets that traverse the stack. These actions are defined in the form of rules. The second component is iptables, which is a generic table structure for the rules and rulesets used by netfilter. The user space tool used to set these rules is also called iptables..."
