1. Click on the Apple Icon, then System Preferences.
2. Select "Network", then on the tab to the left, choose your internet type. (i.e Ethernet, AirPort etc.
3. Then click the "Advanced" button at the bottom, and in the pop up box click the TCP/IP toolbar.
4. Copy down your 'IPv4 Adress', and 'Router' numbers in a document or somewhere handy.
5. Open up your internet browser, such as Safari, Firefox etc.
6. Type the following in the URL bar: http://YourRouterNumber/ With your router number being the one you copied down before from the network bar.
7. A drop-down box will appear, asking for username and password. Type in your login info into the appropriate box.
8. Then select every box under "Protocol" to be labeled as Both. Have every "Start" number to 6112 and "Finish" number to 6119. Under each "IP Adress" box type in the bottom 3 numbers of your IP Adress, as recorded before.
9. Close the browser, open up Battle.Net and host.