The absolute best way to ensure that proper ports are open to the wii is to do the following:
- Set a static IP adress to your Wii through your router (this should be outside the pool of IPs that the router assigns to computers in the network)
- Type that IP into the manual connection settings in the Wii
- For the other manual settings (gateway, net mask, DNS server): in your computer go to start->command->type "cmd" without quotes and in the prompt type "ipconfig /all" without quotes. Copy the relevant information to the wii settings
- Now go back to your router and checkmark an optioned called "DMZ server" and next to it, assign the IP you gave the router
Voila! Now you shouldn't have to worry about closed ports for your wii ;-)