OK, I've got my firewall running well at the moment. Find attached my script (completely stolen from another website). I need to tweak the script to do the following:

1) Cope with dynamic IP - I've set the $INET_IP variable to my current DHCP assignment. How can I change this script to cope with dynamic IP? eth0 is my dynamically assigned internet-facing network card.

2) Block all outgoing traffic except ports 21,53,80,110,119,123,443,3389,6667-6670,8080

Thanks,
Keymoo