Sur le site de Gamespy y disent de faire comme ca :
Two PC Network Cards
If you do not want to use a hub, you can choose to use two network cards in the same machine. One network card will connect to your Internet connection, the other will connect to the console via a crossover cable. The second (console-connected) network card will need to be configured with TCP/IP enabled. You can use an IP address of "192.168.0.1" on it, a netmask of "255.255.255.0" and leave the gateway and other settings blank. Make sure you configure the GameSpy Tunnel application with the network card that is connected to the Xbox when asked to select one.
Je peut recevoir des donnée car je me rend dans les game mais je peut pas en envoyer. c'est ca qui mempeche de jouer