I tried installing IPTables::IPv4 so that I can manage firewall rules from a perl script but unfortunately the ‘make test’ stage failed in such a way that it setup some rules that blocked all traffic to and from the server! To be honest, that’s a pretty bad module if there’s a chance it might lock you out during the install process!
Some 35 minutes later and everything was working ok again thanks to some swift ticket responses from PoundHost tech support.
Rule #1 (along with all the other #1’s), never do anything firewall related on a remote server unless you have a way to back it out if something goes wrong.