Is there a tool for monitoring that iptables (or shorewall or similar) is up and running with a core set of important rules? I need something which alerts me either if the firewall goes donw completely, or if one of a number of rules isn't active anymore, for whatever reason.
I don't want to try the functionality of the firewall by connecting to the ports or (worse) checking if others are connecting.
Server: debian wheezy, standard install. Let's say I want to check that port 80 rule is open for the world and port 8080 only for a certain ip a.b.c.d.
One way would be to save the working rules as a textfile and then have a daily cron job which compares the current rules with this original one, but I'm hoping there's something else that I can use. Is it possible to achieve this in munin or nagios?