you can test 6112 using the telnet trick
vista and 7 dont have telnet installed by default
Open control panel.
Then go into programs.
Then in programs and features
Click ‘turn windows features on or off ‘
on the list that appears check the box beside: Telnet Client.
Then click ok.
start -> run (search vista/7) -> cmd [enter]
telnet uswest.battle.net 6112 [enter]
c [case sensitive must be lower]
it will give your internet ip if port 6112 is open
This is a Battle.net server
Your IP address is [xxx.xxx.xxx.xxx] (this will be your internet ip)
Connection to host lost.