Netfilter is an open-source packet filtering framework for Linux. It is used to control the traffic flowing through a computer network and can be used to block unwanted traffic, such as malware, or limit certain connections. It is typically used as a firewall, and is designed to protect a system from malicious activity. Netfilter also allows users to control which applications and services can access the network, as well as set up security policies and access control. It is a powerful tool for network administrators and provides them with the ability to customize the rules and policies for their networks.
Discontinued active development stopped in 2005.