This check computes the differences between the current output of the
command iptables-save and a cached initial state persisted on the
The check is OK if no changes can be detected and CRIT otherwise.
If the state is CRIT a diff of the cached and initial configurations
is shown in the long output. If a user wants to accept the diff a
service rediscovery can be performed.
One service is created for each system if the agent plugin mk_iptables was deployed.