Console connection issues

I don't know much about satellite setups , only that they are bad because of high ping , but to get 2 xbox ones to play well together you need a gaming router that does UPNP (almost ALL routers will claim this but very few do it well , Netgear is my choice)
it MIGHT be possible to put the ZyXel in "bridge mode" turning it into just a modem and then getting your own router , but if you have other choices of isp (other than satellite) I would look into that also...also , a wired connection is much more preferred...

They are fighting over ports and his is winning , and you also said "modem/router" if that is a modem AND a router (gateway) you have little chance (if any) of correcting this ....more info will help

What Country/State/Province do you live in?

Modem brand & model number:

Router brand & model number:

How many Xbox 360 and Xbox One consoles are connected to this router?:

Wired or Wireless (for each console):

Things you have tried:

Is UPnP Enabled? Yes/No/Unknown:

Do you have a NAT error? If so, what is your NAT type?:

Any Error Codes you encounter:

Who is your ISP? (Internet Service Provider):

Alright well then it sounds like it's just bad issues with the connection, I'll definitely look into setting it to Bridge mode, nabbing a router and seeing if I can move soon even to get a better isp, not a great location and satellite is only available
in the place I moved into a bit ago, definitely glad to hear it's not my xbox slowly dying either ^.^' was worried that something was internally damaged and wasn't acting up until recently.. Anyways thanks for helping my paranoid worries.

Ok it was the Belkin N+ Router. After waiting on hold for about 40 minutes, I find that my router doesn't support the advanced UPnP properties needed to have multiple consoles on the same network. I swung by and picked up a D-Link DIR-835, and out of the
box it didn't work either. Updated the firmware from it's handy "on menu" check for firmware updates button to go from version 1.02 to version 1.03. That still didn't fix it. However, I went manually to the D-Link page, looked up my new router, and downloaded
firmware version 1.04. Voila ~ multiple consoles online. It works superbly too, my son and I had no lag at all and were even able to party chat while playing Mass Effect 3 multiplayer online. Woot! Thanks everyone for the advice and hints.

Hmmm very strange.

So if you logon one Xbox into Xbox live and leave it on the marketplace menus and then start up the second Xbox and run the Xbox live test what message do you get?

You have a DSL modem, what is the make/model of it?