I noticed a couple people having problems enetering games with us on COD4. If you are using a router or a modem with router capabilities (most modems anymore) this might fix the problem. First test you Live connection on your xbox under network settings which is on the system blade and make sure everything is confirmed, xbox live is connected, and NAT is open. If your NAT is moderate or closed, you are having a communication problem with your router and this should fix it. If it is open then this isnt gauranteed to work but you can still try it.
Step 1: Set a static IP address on you XBOX.
Go to "network connection" on the "system" blade. Select "edit settings", "basic settings", "IP address", and then"manual". Change the IP address to your routers IP address and change only the last digit or digits to any number between 2 and 254 (google your routers IP adress for the easiest way to find it or I have some common ones listed below). Make sure you remember or write this number down because you'll need it later. Next, change the "subnet mask" to 255.255.255.0 . Next, change "gateway" to the IP address of your router.
Go back and select "DNS settings" under the basic settings tab. Change your "primary dns server" to your router's IP address. the "secondary dns server" can be changed to the dns server given by you ISP, but doesn't need a number if you can't find out what it is.
Common router IP Addresses:
Step 2: Opening ports
This step you'll need to be on your computer. These directions won't apply to every router cause of differences in the menus but the idea is the same for all of them. Because nichols asked me about this I'll give you an idea of how to do this with a linksys router.
Enter your routers IP address into the navigation bar of your browser and hit enter. This will take you to your router settings. Most routers will ask you for a username and password. If you have not changed this, the Linksys default username and password are both "admin" in lowercase. Most routers use "admin" as the username and either "admn", "password", or "1234" as the password. The book for your router should tell you what it is or google your model number to find it.
When you are into the settings, look for an option for "port forwarding", "forward ports", or something similar. I know some d-link routers use "virtual server" as the title. This setting is usually found under the advanced settings or on some linksys routers it will be under "applications and gaming". Under "name" or "application" enter xbox or anything else that will help you identify it. Some will have a port range or just a single field for a port. If there is a range, enter the same number twice. The port that should be opened are:
3074 UDP / TCP
These are the required ports but the following ports can also be opened now or after you have tried just these three:
2074 UDP / TCP
After entering the ports to be opened, enter the static IP address you enter on the XBOX for each one of the ports opened. Make sure each port is enabled or marked as always open depending on your router. Make sure your settings are saved.
Step 3: Check your connection
When you are done with all of the steps above Test your XBOX Live connection again. The test should read the following:
Network Adapter - Wired
IP Address - Confirmed
DNS - Confirmed
MTU - Confirmed
ICMP - Confirmed
XBOX Live - Connected
NAT - Open
If the NAT is still not saying open, make sure you opened all the ports above. If none of them worked it could be a problem being caused by your modem. Setting your modem to Bridge Mode (takes away router functiions, which you don't need if you have a router) or turning on plug n play on your modem may fix this problem. Hopefully this fixes any problems you had. Anymore questions feels free to ask.