This concept will work for practically any sip server, assuming it runs linux and uses iptables. I wrote this looking forward into the future of sipxecs, where protection mechanisms of certain levels are being added at the proxy level. Until users adopt and deploy 4.6 (some are slower than others, right Windows XP users?), this can be considered a crutch to help them stay functional in the event of a DOS attack or a script to try to penetrate weak security.
It should be trivial for any network admin to edit and make it functional on your system.