descriptionferm is a tool to maintain complex firewalls, without having the trouble to rewrite the complex rules over and over again.
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last changeThu, 19 Feb 2015 07:34:01 +0000 (19 08:34 +0100)
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        Max Kellermann <>
        Auke Kok <>


ferm is a frontend for iptables. It reads the rules from a structured
configuration file and calls iptables(8) to insert them into the
running kernel.

ferm's goal is to make firewall rules easy to write and easy to
read. It tries to reduce the tedious task of writing down rules, thus
enabling the firewall administrator to spend more time on developing
good rules than the proper implementation of the rule.

To achieve this, ferm uses a simple but powerful configuration
language, which allows variables, functions, arrays, blocks. It also
allows you to include other files, allowing you to create libraries of
commonly used structures and functions.

ferm, pronounced "firm", stands for "For Easy Rule Making".

Installing ferm

  make install

The package does not need to be compiled, just make sure you have perl
(which is present in any base linux system) and iptables (including
iptables-save and iptables-restore), and the a kernel supporting

Run the make install install script as root to install the package in
it's best location, so it can be reached from the command line when
called. The manual page will also be installed.

That's all!

Uninstalling ferm

  make uninstall

Ferm can now be quickly removed from the system by issuing a "make
uninstall" command (as root, of course). This will not remove any
configuration files of course!

Getting started

The ferm(1) manpage provides extensive documentation about the ferm
syntax.  To get started, try one of the example files, and modify it
for your needs.

If your machine is already firewalled and you wish to switch to ferm,
the "import-ferm" script comes handy.  It converts the current
firewall rules to a ferm configuration file:

  import-ferm >/etc/ferm/ferm.conf

After that, let ferm install the new ruleset:

  ferm /etc/ferm/ferm.conf

Be careful, don't lock youself out of remote machines!  Use the
interactive mode (--interactive, -i) often!
2015-02-19 Bernd ZeimetzAdd support for the ipvs module.master
2015-02-19 Max Kellermannsupport various target modules
2015-02-19 Max Kellermannsupport new SET parameters
2015-02-19 Max Kellermanndoc: add documentation for new modules
2015-02-19 Max Kellermannsupport various match modules
2015-02-19 Max Kellermannsupport new CONNMARK parameters
2015-02-19 Thibault VINCENTFix confusing typo in error message
2015-02-19 Thibault VINCENTAdd support for netfilter module rpfilter
2015-01-02 divby0added BROUTING to the list of built-in chains (used...
2015-01-02 Max Kellermanntest: add unit test for @defined()
2015-01-02 Max Kellermann@defined() support functions
2015-01-02 Max Kellermann@defined() requires $ prefix
2015-01-02 divby0added the @defined function
2015-01-02 Max KellermannNEWS: rephrase line about exit status
2014-12-28 Max KellermannNFQUEUE: support queue-balance, queue-bypass, queue...
2014-12-28 Max Kellermanntest: sort ferm output
2 years ago v2.2
2 years ago v2.1.2
3 years ago v2.1.1
4 years ago v2.1
4 years ago v2.0.9
5 years ago v2.0.8
5 years ago v2.0.7
6 years ago v2.0.6
6 years ago v2.0.5
6 years ago v2.0.4
7 years ago v2.0.3
7 years ago v2.0.2
7 years ago v2.0.1
7 years ago v2.0
7 years ago v1.3.5
7 years ago v1.3.4
9 months ago master
7 years ago ferm-1.3.x
8 years ago ferm-1.2.x
9 years ago ferm-1.0.x