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Developer(s)Darren Reed
Stable release
5.1.2 / 22 July 2012; 9 years ago (2012-07-22)
  • [cvs:// cvs://] Edit this at Wikidata
Operating systemFreeBSD, NetBSD, Solaris, illumos, OpenIndiana, Linux, HP-UX
TypePacket filtering
LicenseBefore 4.1.35 and 5.1.1: IPFilter License (BSD-like); Since 4.1.35 and 5.1.1: GNU GPLv2[note 1]

IPFilter (commonly referred to as ipf) is an open-source software package that provides firewall services and network address translation (NAT) for many Unix-like operating systems. The author and software maintainer is Darren Reed. IPFilter supports both IPv4 and IPv6 protocols, and is a stateful firewall.

IPFilter is delivered with FreeBSD,[2] NetBSD,[3] Solaris 10 & 11,[4] illumos,[5] OpenIndiana[6] and HP-UX.[7] It used to be a part of OpenBSD, but it was removed by Theo de Raadt in May 2001 due to problems with its license.[8] It was subsequently replaced in OpenBSD by PF, which was developed by OpenBSD's own developers. DragonFly BSD removed its support for IPFilter in May 2011.

IPFilter can be installed as a runtime-loadable kernel module or directly incorporated into the operating system kernel, depending on the specifics of each kernel and user preferences. The software's documentation recommends the module approach, if possible.


  1. ^ The full license text can be found from IPFILTER.LICENCE file of its source directory. The author later also licensed version 5.1.2 under the previous BSD-like license for use in FreeBSD project.[1]

See also


  1. ^ "FreeBSD base Revision 254219". Retrieved 9 Jun 2020.
  2. ^ "IPFILTER". FreeBSD Handbook. FreeBSD. Retrieved 2019-11-10.
  3. ^ "ipf - alters packet filtering lists for IP packet input and output". NetBSD. Retrieved 2019-11-10.
  4. ^ "IP Filter in Oracle Solaris (Overview)". Oracle Solaris Administration: IP Services. Oracle. 2012-03-01. Retrieved 2019-11-10.
  5. ^ "Features". illumos. 2019-10-02. Retrieved 2019-11-10. illumos uses ipfilter for firewalling. Using ipfilter you can create firewalls not just for the host system, but also for zones and hardware virtualized systems.
  6. ^ Števko, Adam (2012-02-08). "System Administration: Firewall". OpenIndiana Handbook. Retrieved 2019-11-10.
  7. ^ "HP-UX IPFilter". HPE. 2020-03-31. Retrieved 2019-12-04.
  8. ^ de Raadt, Theo (2001-05-30). "Remove ipf". openbsd-cvs. Retrieved 2019-01-31.