Do you have anything in your firewall logs? Try to make an additional IP address through Virtual IP's menu (use carp) and then assign that to your NAT rule for the outside IP address to be used and see if that works. Additionally, from a computer behind pfSense, go to http://www.whatismyip.com and verify that this is the IP address that you think it should be. What pfSense version are you running?
Curtis
