BTW everyone you can open up your router and host by doing the following:
go to internet explorer
on the address bar, type in "192.168.1.1", or whatever your individual computer address is.
Username should be blank by default, and for password, type in "admin".
Go to "Administration" tab, and enable UPnP setting.
Then your NAT will end up Open.
But my router is linksys, and might be different from all. Try to find how to get to your router's Administration by going to "http://us.blizzard.com/support/article.xml?locale=en_US&articleId=21073&parentCat egoryId&pageNumber=1&categoryId=3617".
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