So I've been having this problem more then once and it's now becoming rather annoying I have to say.
There are times that my Xbox wont read my Ethernet cable. By that I mean it doesn't even acknowledge that there is an Ethernet cable plugged into the xbox and the router.
I had just gotten internet again and I have Verizon Modem/Router combo, so my usual D-Link has become obsolete now. But even so I have been having this problem even with my D-Link router. I've tried many Ethernet cables and they all do the same thing. I'd use the same cable on my laptops and even my desktop and it's acknowledged just fine. So I know it can't possibly be a faulty cable.
I don't know what the problem is and how to fix it. If it's something faulty in the Xbox itself.
If anyone has any fixes to this please tell me. It's annoying to have to fight with your xbox to acknowledge your Ethernet cable let alone getting it to read your connection.(Though I have yet to run into that.) Usually once it acknowledges my cable then everything is perfectly fine.