I just used the procedure to reset my ports provided by Slingbox. They have a lot of good info here....you just have to find it. Here's the url for the procedure I used: http://support.slingbox.com/get/network-assistant.html. I suggest you copy the following info for your unit on your quick start guide:
Slingbox IP Address: Slingbox Port: Gateway IP Address: Router Brand: Router Model:
You can use it whenever you need to reconfigure port forwarding.