Xbox 360 provides the option to play in multiplayer mode: this is where users can connect to the internet and play with other players who are also online. If users are unable to play online with two Xbox 360s, the issue may be related to the settings of the Xbox. Attaching two Xbox 360s to the same internet connection may create problems if the network configuration settings are incorrect. The correct settings have to be entered in the Port Range Triggering Page. Both Xbox 360s must be configured to be assigned an IP address automatically and the MTU must be set to 1500. The settings must be saved otherwise the users will be unable to play online with two Xbox 360s.
I bought an Xbox 360 about two years ago, then my cousin bought one too. We wanted to play with our friends but couldn't; well I could but on his Xbox it said that the connection with the host had ended. If he entered the game first, then the same message would appear on mine and I couldn't play. Is it because we were using the same internet?
Here's to anyone who is getting a little confused as to what to enter in the port range triggering page. Firstly make sure the DMZ is disabled, the Upnp is on and you are NOT forwarding any ports using single port forwarding.
Then enter the following in the Port Range Triggering page:
The Application Name doesn't matter: call each one what you like (e.g Xbox1, Xbox2 etc.).
Xbox1 Triggered Range (Start Port: 52) (End Port: 54) Forward Range (Always the same as Triggered Range, so 52 and 54 in this case) TICK THE ENABLED BOX.
Xbox2 Triggered Range (Start Port: 79) (End Port: 81) (Forward Range 79 and 81) TICK ENABLED.
Xbox3 Triggered Range (Start Port: 87) (End Port: 89) (Forward Range 87 and 89) TICK ENABLED.
Xbox4 Triggered Range (Start Port: 3073) End Port: 3075) (Forward Range 3073 and 3075) TICK ENABLED.
N.B: Remember to click Save Settings at the bottom. I am sure many forget to do this, hence why they still experience problems!
This method above worked for me immediately, after trying a number of other solutions. I too found the information a bit vague at times with regards to what numbers to enter in the boxes etc. so I hope this information will help others in the same situation. I turned two Xbox's with Open and Strict NAT into two with Open Nat.
You also need both Xbox's to be set to automatically be assigned an IP address: ignore all the advice to have a manual IP, as this doesn't seem to work and actually appears to make things worse. Also make sure you haven't messed with any other router settings other than those above and that your MTU is set to 1500.