Posted 24 July 2008 - 09:50 PM
Short: Xbox 360 can't connect to internet, fails at MTU, Firewall seems to be the problem, changing MTU values on interfaces of firewall does not fix it
Long: So, here I am in a new apartment and we are setting up a new network, the topology is as follows:
Cable modem --> Firewall --> switch --> Linksys WRT54G with DDWRT --> XBOX 360
The connection between the router and 360 is wireless.
When I test connection to XBOX Live, it fails at MTU....every time. Last year I tried a similar setup with a different 360, only that one took the WRT54G completely out of the picture. The 360 was connected directly to the switch. The same problem, 360 Live test fails at MTU. So we know the WRT54G is not the problem.
What does work: If I connect to XBOX 360 to the switch, then directly into the modem, not using the firewall, and it worked.
So, the switch and WRT54G are not the problem, the firewall is the problem. I have tried changing the MTU values of both the red (connects to modem) and green (connects to switch) interfaces to 1492, 1400, and of course the default 1500. Still fails at MTU, every...single....time.
So, what can I do to try and get this fixed? Microsoft was so help at all, they said nothing more than "You have an incompatible networking device" which is a bull**** excuse.