Configuring a Linksys BEFSR41 Router for Animal Crossing

The Wii game Animal Crossing: City Folk, which was released on November 16, 2008 in the U.S. allows one to visit friends who also have Wii's on which they are running the game. But in order for someone to visit you, you must have your router/firewall configured so that the appropriate firewall ports are open. If it isn't configured to allow data to pass through to the relevant ports on the Wii, someone you've invited to visit you will see the error message below on his or her Wii. 
Communication error. You
have been disconnected
from Nintendo Wi-Fi
Connection. Try again.

For help, visit
support.nintendo.com
<86420>
The ports that should be opened are User Datagram Protocol (UDP) ports. But which ports? What is extremely aggravating is Nintendo's answer at Error Code: 86420, which is shown below:

In order to solve this problem, you may consider adjusting your router's Port Forwarding settings*. Each router is unique, so consult the owner's manual for your router or contact the manufacturer for specific information on working with your router's ports. For your information:

So the Wii needs to use all but one of the 65,536 possible ports (the only one they didn't include was port 0)? Why can't Nintendo bother to provide specific port numbers? This advice presumes one only wants to use a Wii and no other system that might use UDP ports on his or her Local Area Network (LAN). What happens if you have a PC behind the same router to which the Wii is attached that has an application or applications that also utilize UDP ports? If you follow Nintendo's advice you have to reconfigure your router every time you want to switch from using that appliation on the PC to allowing a friend to visit you using the Wii.

Presuming you really want to allow a friend to vist, though, to open those ports on a Linksys BEFSR41 router, take the following steps:

  1. Open a web browser, such as Internet Explorer or Firefox and enter the IP address of your router into its address field. The default router address is 192.168.1.1, so you would enter http://192.168.1.1, if you haven't changed the IP address.
  2. When prompted for the username and password, enter the ones you supplied when you configured the router and click on OK. If you didn't set those, the default values are as follows:

    Username: admin
    Password: admin
  3. Click on the Applications & Gaming link near the top of the webpage.
  4. On the next webpage that appears, select Port Range Forwarding .
  5. Put the following values in the Port Range table, assuming the IP address for your Wii is 192.168.1.5. It likely will be something else, so make sure you are putting in the correct address. And, if you don't have the Wii's IP address set to a static value, i.e. it is being assigned by DHCP, it may change whenever you reboot the router, power the Wii off and on, etc., so it is best to have the Wii's IP address set to a static address.

    If the Wii was assigned a dynamic address by the Linksys router, it will have an address in the range of 192.168.1.100 to 192.168.1.150, unless you've changed the DHCP-assigned address range. You can see the IP addresses the router has assigned via DHCP to devices connected to it by clicking on the Status tab and then clicking on the DHCP Client Table button. You should see "Wii" listed for one of the client hostnames, if the Wii got its address by DHCP.

    You can use whatever you like for the name in the "Application" field, it's just a description for your own benefit in recalling its purpose when you view the port forwarding settings in the future.

    Make sure you check the Enabled box to enable the services you have defined. Port Range Forwarding will not function for the ports you've entered if the boxes for them are unchecked.

    ApplicationStartEndProtocol IP AddressEnabled
    Wii165535UDP192.168.1.5 Checkbox
  6. Click on Save Settings.

Another alternative to port forwarding is to configure the router so that it supports a "demiliartized zone (DMZ)", though I've heard complaints about the DMZ option not working for some on this router. You can set up a DMZ by going to the DMZ screen under the Applications & Gaming tab. The DMZ screen allows one local system to be exposed to the Internet for use of special-purpose services such as Internet gaming and videoconferencing. DMZ hosting forwards all the ports at the same time to one PC, i.e. instead of forwarding just the ports needed for a particular application, you forward all 65536 possible ports for both TCP and UDP traffic. Port Range Forwarding is more secure because it only opens the ports you want to have opened, provided, of course, that you don't have to forward almost every possible port, because Nintendo doesn't deign to provide information on the specific ports needed. But, this may be less of an issue, if the DMZ host is some system with its own firewall software running on it.

To use the DMZ feature, instead of the port range forwarding procedure described above, select Enable on the DMZ screen and put the IP address of the host, e.g. the Wii, in the DMZ Host IP Address field. Then click on Save Settings. You need to be aware that, unless you've specified a static IP address for the Wii, that rebooting the router, powering the Wii off and on, etc. may result in the IP address changing. If its address changes you will have to put in the new address in the DMZ Host IP Address field, so it is better to assign a static address to the Wii.

Unfortunately, to date, I haven't been able to determine which specific ports need to be opened on a firewall to allow someone to visit. I sniffed the traffic coming from another Wii a couple of times, but it didn't appear that the same destination port was being used each time, so this is just a way to make it work for a Linksys BEFSR41 router without knowing the specific ports required for the application on the Wii.

References:

  1. Firewall/Antivirus/Antispyware/Adware Compatibility Info
    Nintendo
  2. Linksys BEFSR41 configuration - Static IP Addresses
    HansenOnline.net