Adolph, go to ip 65.70.54.234 and tell me what you see..

I am at Diedrich's right now, and that is the ip address that everybody outside of the Diedrich's network sees.

You are right in assuming that this network, like most networks, makes use of NAT. But it is precisely because they are using NAT that we will not be able to host a game from inside their network.