Windows XP and Mac OS X ship with firewall services built into the operating system. These services are disabled by default. If you have turned these services on, you may need to configure these services to allow the game to access the Internet. We have step-by-step instructions for configuring these firewalls to work with the game:
If you need further help configuring your firewall, router, or proxy first try to reset your router and modem by following Step 3 of Connection Troubleshooting. You may need to contact the manufacturer for more specific assistance.
Additional firewall and port forwarding guides can also be found at Portforward.com. You will need to search for your specific device or software and follow the instructions listed there. If you still have trouble setting them up, please contact the manufacturer for additional assistance.