Can't help directly, but maybe I can indirectly. I am with Dish but do not have the hopper setup. However I do have their sling adapter for my receiver. I am able to connect to my receiver and did not have to do any configuring in my router whatsoever, but I am on Comcast.
Have you set yourself up at
http://www.dishanywhere.com/?
Can you connect with your phone? I am on android and their app works for me. (I am also able to connect with my laptop of course.)
Go to
http://www.satelliteguys.us/. They have a forum dedicated to the hopper and a lot of information regarding sling. Pretty helpful people over there.
I am about 1200 miles away from home right now and will be for the next two months. I can connect to my receiver and watch recorded shows from it (or live TV if I wish). The internet connection I have here is with Comcast at their slowest tier of service. I am amazed at the picture quality. It takes a few seconds to sharpen up, always goes black twice for a brief second or two and then it's great.