No way man,
I have tried everything and i do mean EVERYTHING concievable.
Nat filter (non existent but if it did it would probably rectify the issue) , upnp (the CGN3's is not very good) , DMZ, port forwarding /triggering, hardwired/wireless, SIP ALG, firewall, firmware, bridging, etc.
Unfortunately the CGN3 just isnt cut out for multiple Xbones.
We are basically expecting a car to fly. It just does not work.
I will be purchasing one of the routers either mentioned in this thread or in the xbox forums.
If you end up going down to ONE console, I highly recommend port forwarding easy to do and about a million how to's and youtube videos on how to do it.
I have a Hitron CGN3AMR modem and use it wirelessly to play on my Xbox 360. Currently the NAT type is moderate and I want to open it. How would I go about doing this?
Xbox now allows manual port assignment.
The latest Xbox "Fall Update" which was released today allows you to assign a manual port for Xbox live.
No need for UPNP anymore or multiple ports being forwarded.
I shut down all my rules for XBOX and only left port 3074 open and I had an OPEN NAT.
I remember someone needing help with multiple Xboxs on the same network and this will solve that problem. Just assign each Xbox a different port and forward those in your router pointing to the correct Xbox and everything should be fine.
Some text i found on REDDIT.
"Alternate multiplayer port selection: Under Network settings, Advanced settings there's a new button labeled Alternate port selection. For home networks where UPnP is problematic or unavailable and where multiple Xbox consoles are present, customers can now select an alternate port for multiplayer and chat to use. The default port for Xbox multiplayer and chat is UDP 3074, and when working around NAT issues you can set up either port forwarding or port triggering for this port & protocol to open up the NAT type for a single console. However, this option is only available to one console at a time if all consoles are using UDP 3074. With this new option, you can select a different UDP port from a drop down menu for each console so that you can setup port forwarding rules for each console on your home network. When the console binds to the new port, it will also attempt to port map via UPnP on this new port in case the UPnP issues with the home router are intermittent."