IPFilter, also called ipf is a packet filter, a software that can be used as a firewall or as a NAT to translate Internet addresses.

IPFilter is a very portable package filter. He walks among others on the operating systems FreeBSD, NetBSD, Linux, SunOS, Solaris, HP- UX, Tru64 UNIX. IRIX, and QNX.

IPFilter has been written by Darren Reed since the early 1990s; Version 1.0 was released on 22 April 1993. IPFilter is active as open source software developed ( BSD-like license). Currently, the 5.1 series, which was published on May 9, 2010.

See also: pf, ipfw, iptables