Ok, thanks. But what ip address must he give me? his router ip or his pc ip? And how can he look for those ips to give me them?

Hi: Me and a friend are trying to connect online to have a fight but always i try to connect to him appears a mis-typed cdkey and we dont know what does it mean. He has a dinamic ip and i have an static one. If he tries to connect to me everything is ok but i cannot connect to him and we want me to ...