This was never an issue with previous routers, but I now use the Cisco Linksys EA4500, and when I enable my single port forwarding for various ports for my Apple TV and XBOX 360, my Internet would stop working. I'd disable the port forwarding, it'd work fine again, and it does this every time consistently.

Okay. So I dug a little bit, and it turns out when my single port forwarding is enabled, my DNS fails. So... I don't really understand why that would be the case. Anyone have any suggestions/ideas on how to make this all work out? With previous routers this was never a problem.

I was thinking it's how my ISP works, but then again I had this same ISP while I was using my last router, and this wasn't happening then. So I'm assuming it's the router in some way, shape, or form that's the problem. Could it be a bug?

I should note that I have the latest firmware. I even updated to an alternative firmware that enables their 'connect cloud' feature to see if that might help. Nope. In fact, they brilliantly decided to provide less options for your router with this new setup... unless you're connected to the Internet. So, yes, once I found the new way to do single port forwarding using the interface that's only available when the entire connection works normally, it did the same thing with the DNS, locked me out of those settings, and the offline ones don't allow you to edit single port forwarding anymore. Morons.

Anyway, I've just finished resetting my router to factory settings and re-configuring it back to working order.

I'd still like to enable port forwarding without it causing this problem.