That isn't really relevant to the problem they were working around. The problem is that many firewalls block outbound ports other than port 80, 443, and some ot

That isn't really relevant to the problem they were working around. The problem is that many firewalls block outbound ports other than port 80, 443, and some other very common ports. Put another way, if both sides block 80 incoming, their only hope is fancy NAT-punching techniques. But those NAT-punching tricks are useless if they are using a port that is completely blocked on the outbound side.