For those interested...the Devs weigh in.
Hi,
Thank you for contacting Activision’s Technical Support. I'm sorry to hear about your problem. This is a router issue not a problem with the game.
To setup for multiple users:
1) Right-click on the Call of Duty 4 icon you use to start the game.
2) Select Properties.
3) In the Target field you'll see a line like "C:\Program Files\Activision\Call of Duty 4 - Modern Warfare\iw3mp.exe", add the net_port command to specify a unique communication port for each system. The complete field should look like this:
"C:\Program Files\Activision\Call of Duty 4 - Modern Warfare\iw3mp.exe" +set net_port 28960
4) Click OK.
5) Repeat for each system behind the NAT, adding one to the net_port selected (28961,28962,28963 etc.. )
While the first player behind the NAT joins fine, adding additional players is problematic in the default configuration. Symptoms include rejected challenges, invalid cdkey, dropped delta packets, and severe "connection interrupted" messages.
By default, Call of Duty 4 clients send and receive data over the same port, causing the server to treat multiple clients as a single data connection.
For more information on networking please visit
PracticallyNetworked.com
Customer - 06/17/2008 07:38 PM
My son and I have two different copies of the game. He downloaded his from a service called Steam (pardon my spelling if wrong) and I bought mine from a game store. Whenever we try to play together behind the same modem/router we get a "Connection Interrupted" message. After which, the server you were just on will not accept you for a short period of time. It's almost like an MD5 kick on Americas Army only there's no warning...you just get the "connection interrupted" message and icon then eventually is disconnects. I was given a fix for the router set up that someone on another forum suggested. His post was the following:
Go into your router and find your settings find this
UPNP Enabling
Make sure thats enabled that happend to my son and I and that fixed the CI problem
However, this did not fix the problem as UPNP was already enabled. Could you please help me. The whole reason I bought the game was to share the experience with my son.
My router is a Linksys WRT54G. I have comcast's highest connection speed. Both computers are good solid gaming computers.
Any help is greatly appreciated.
Dave