If you are having difficulty connecting to the Modern Warfare 3 servers, try the following solutions:

1. Check http://www.callofduty.com/mw3/status for the status of the Call of Duty servers. The servers may be down for maintenace.
2. Restart your console and try accessing the server again.  
3. Disable any firewall or security features on your router.
4. Set Port Forwarding on your router [Click here to learn how].
5. For certain Netgear routers (DGN-1000) - Change your ADSL multiplexing method from VC-Based to LLC-Based [Contact Netgear to learn how].

MW3 uses the following ports:

Xbox 360: 80, 53, 3074 TCP (Transmission Control Protocol) and 88, 53, 3074 UDP (User Datagram Protocol)

PlayStation 3: 80, 443, 5223, 3074 (TCP) and 3074, 3478, 3479 (UDP)

Wii: 80,,443, 28910, 29900, 29901, 3074 (TCP). All all tracffic to all destinations on UDP.

PC (Steam): UDP: 27000 - 27015, 27015 - 27030, 3074 and TCP: 27014 - 27050, 3074

The most common server solutions are available above; however, there are more in-depth, console specific solutions available in our knowledge base.   

PC Specific Help

PlayStation3 Specific Help

Wii Specific Help

Xbox 360 Specific Help