PF was originally designed as replacement for Darren Reed's IPFilter, from which it derives much of its rule syntax.

Features such as pfsync and CARP for failover and redundancy, authpf for session authentication, and ftp-proxy to ease firewalling the difficult FTP protocol, have also extended PF.

Also PF supports SMP (Symmetric multiprocessing) & STO (Stateful Tracking Options).

Logs may be monitored using standard utilities such as tcpdump, which in OpenBSD has been extended especially for the purpose, or saved to disk in the tcpdump/pcap binary format using the pflogd daemon.

Apart from running on its home platform OpenBSD, PF has been ported to many other operating systems, however there are major differences in capabilities.