Code:
<!--<address>75.184.73.187</address>-->
<!--<localaddress>192.168.5.52</localaddress>-->
These lines are not commented out for me, I have had to tweak them to get my server working.
I have a linksys router, getting a static IP. 2 comps directly plugged into it.
Computer A (host) can join any server. Computer B can join any server EXCEPT the server computer A is hosting.