Advanced Policy Firewall (APF) is an iptables(netfilter) based firewall system designed around the essential needs of today’s Internet deployed servers and the unique needs of custom deployed Linux installations. The configuration of APF is designed to be very informative and present the user with an easy to follow process, from top to bottom of the configuration file. The management of APF on a day-to-day basis is conducted from the command line with the ‘apf’ command, which includes detailed usage information and all the features one would expect from a current and forward thinking firewall solution.
The technical side of APF is such that it embraces the latest stable features put forward by the iptables(netfilter) project to provide a very robust and powerful firewall. The filtering performed by APF is three fold:
- Static rule based policies (not to be confused with a “static firewall”)
- Connection based stateful policies
- Sanity based policies