Quote Originally Posted by Felmin View Post
after I changed to a newer modem provided by my ISP.
Can bet this is the problem. Those things often come with customized NAT/LAN settings that you can't change, and that may screw with online play. Use a bridged port on that thing, but chances are no port is set to bridged. You can find this out by checking the manual of the modem. Ask the ISP if you don't want to play with modem settings or there is no other option.