Media Center Extenders need to be setup on the same subnet as the Media Center PC
I had posted a while back that I had trouble getting my Media Center Extender setup on a different subnet than the PC. I promised details, and I even got a few mails from people asking for details. Apologies for the delay - here, without further ado, are the details.
I live in a community that has fiber connected directly to every home. The catch (besides all the hidden fees you pay when you move there) - you don't actually own the router that sits in the wiring closet. The network provider owns the router, and will not let you configure the router at all. You can however email the network provider and ask them to make configuration changes. The downside of that approach is that they tend to just say no. Since I wanted wireless, I had my own wireless router plugged into their router, and all of my PCs and devices were plugged into that router. I made sure that my router had all of the necessary ports open, but the main router coming into the house, was closed down, which was causing problems. The router that I couldn't touch was configured to the strictest NAT setting, so I couldn't join my friends on Xbox Live. My Xbox worked great as a Media Center Extender though, since it was on the same router (and thus, subnet) as the Media Center PC.
After much talking to my network provider asking them to change some of the router settings so that my Xbox would connect to Live (KB article talks about this here), they agreed to not make those changes. They decided instead to setup my Xbox in the DMZ of the router, so that it alone could brave the cold of the internets without risking the other computers/devices on my network. So I unplugged my Xbox from my router and plugged it directly into theirs - problem solved. I could now play Xbox Live with my friends. Except that now the Xbox couldn't see my Media Center PC, so it wouldn't work as a Media Center Extender. This was a no-go since I primarily use my Xbox as an Extender.
I searched the internets far and wide trying to find out what the problem was now, and even called both the Xbox support as well as my network provider. Nobody knew what was wrong. One day at work, after a particularly frustrating phone call to Xbox support, I went into my developer's office to vent my frustration over the situation. He looked at me a little funny, and then reminded me that he had worked on Extender and knew what my problem was. He proceeded to tell me how routers work, with subnet masks, unicast vs. multicast, etc. I'm not a networking guy, but what he said made sense - and the bottom line is that Media Center Extenders will only connect to a Media Center PC that is on the same subnet.
To get my specific configuration working, I again contacted my network provider and this time had them assign the MAC address of my wireless router to the DMZ of their router, and then plugged my Xbox back into my router and everything worked again. I got my Xbox Live and my Extender working. All of this so that my network provider wouldn't have to open up the ports listed in the KB article above. But there you have it - details. Again, apologies for the delay.
