shorewall-monitor for Xymon is an extension to monitor a locally running shorewall (or shorewall-lite) firewall.

Shorewall is a high-level tool for configuring Netfilter, the firewall system used on GNU/Linux. It can be used standalone but also allows to deploy firewall rulesets from a central system (that has installed shorewall like in the standalone case) to satellite systems (running shorewall-lite).

shorewall-monitor was created for a large setup with many satellites but can also be used for a single/standalone installation.


shorewall-monitor reports the following information:

  • status of shorewall(-lite):

    • started / stopped / cleared: green / yellow / red

    • execution problem (red). If no shorewall-installation is found (or executing shorewall fails) this is reported with a “red” status.

    In addition to the decoded/interpreted state of the shorewall-firewall the full output of shorewall[-lite] status is reported too (possibly saving a login to the machine for diagnosing).

  • metrics to identify the current ruleset:

    • the full ruleset (output of shorewall[-lite] show) if desired (can be disabled in shorewall-monitor)

    • the number of lines of the currently running ruleset

    • ruleset recently reloaded: If the ruleset was (re-) loaded less than 1800 seconds ago a yellow status is reported.

  • metrics on the firewall-script generated by shorewall(-lite):

    • the “version” of the compiled firewall-script (the header written to the file)

    • md5-hash of the compiled firewall-script


Should work with any Xymon or Hobbit version (v4.2+) and shorewall v4.4+.

Tested with

  • Debian Wheezy (7.x), Jessie (8.x), Stretch (9.x) with xymon-client from the offical repository.
  • shorewall and shorewall-lite version 4.5.x, 4.6.x.


Copying and distribution of this package (shorewall-monitor), with or without modification, are permitted in any medium without royalty provided the copyright notice and this notice are preserved. This package is offered as-is, without any warranty.


Version Release Date
0.7 2011-11-12
0.6 2015-02-27
0.5 2015-02-10