Hi I spent the past twelve months going through the IPF / PF (4) - OpenBSD / iptables trek. What a long hard trip it was. It's difficult to give a simple answer. Might be best to stick to iptables for ease of use. If you fancy a challenge have a go at IPF. OpenBSD is good for security but it doesn't like to help you with ISDN cards and some other internet/network interfaces can be difficult. Best to experiment a bit :) Richard