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Nintendo announced that Nintendo Wi-Fi Connection would be discontinued on May 20, 2014. This impacted all Nintendo DS and Wii games with online features that were directly using Nintendo WFC, which included Mario Kart Wii. Wiimm had been analyzing the Mario Kart Wii network traffic since November 2012, and had already written a helper tool named mkw-ana. And so he decided, together with other people, to create the Wiimmfi Project (formerly Wii-Server Project) to replace Nintendo's servers for Mario Kart Wii and for other games, if possible.


wiimmfi.de replaces nintendowifi.net in games. All games must use this new domain and change https to http (see below).

The domain wiimmfi.de was registered by Wiimm for this project. If Wiimm discontinues this service at any time in the future, he will give away the domain, the software and the data base content.

State of the Project

On May 10 2014, 10 days before Nintendo shut down their NAS and disconnected themselves from GameSpy, Wiimm released Wiimmfi Patchers. Since that date, Wiimmfi was publically usuable. At first, the server only supported Mario Kart Wii, including the different Custom Track Distributions. However, more games have been enabled, tested, and are now fully supported.

List of all Wiimmfi games (supported, test and disabled)

The game lists also contains information about issues.

Connecting to Wiimmfi

Wii games must be patched to access Wiimmfi, as Nintendo Wi-Fi Connection originally used SSL for login. However, a variety of patchers exist for Wii games:

  • CTGP-R automatically includes Wiimmfi support in-app, with no setup required.
  • Auto Wiimmfi Patcher is a home-brew app that will automatically patch Wii discs when launched (however, it is required to launch the app every time) - this app can also be accessed by setting the Wii's DNS to and launching the WC24/Wii Shop Channel license agreement.
  • Auto WiiWare Patcher can patch most WiiWare WADs to allow enable Wiimmfi access.
  • Wiimm's Disc Patcher can permanently patch disc images.
  • Updated USB Loaders can also automatically patch USB images for Wiimmfi - recent versions of USB Loader GX and WiiFlow can automatically patch for Wiimmfi using a Private Server option.


Wiimm originally implemented the server in PHP, so that the servers were created quickly. From the beginning of development, it was known that the servers must be ported to C/C++ to improve performance. While developing, there were issues due to using PHP, and 2 servers have thus been ported to C.


NAS is the Nintendo Authentication Server. The Wii used naswii with HTTPS, and the DS used nas (which supported HTTP) with HTTPS. They are interchangeable. On Wiimmfi, the server is implemented using APACHE2 and PHP5. At the moment, logins are accepted with old and new profiles. New savegames send a request to get their unique console nickname from the server.


When entering the WFC, the Wii connects to GPCM using TCP. The connection is closed upon leaving WFC. The server is used for general maintenance and for message exchange between the clients.

It is currently implemented as PHP script. The interprocess communication (transferring messages) is implemented with UNIX sockets. To improve the performance and to allow a better interprocess communication, a C-server was written. It is still in development and supports a model with supervisors and workers. Since March 2016, the new server is in use at Wiimmfi's test server.


GPSP is used to retrieve information about friends. The Wii connects frequently using TCP. Nintendo's GPSP server was used to retrieve the profile_id and nick pairs before shutdown.

On Wiimmfi, GPSP has been implemented as PHP script.


MASTER listens on port 27900 via UDP. Games send status records to MASTER. MASTER stores them into a game specific table, where other clients can retrieve the information using MS (see next point).

At the beginning, MASTER was implemented as PHP script. In September 2014 it was replaced by a giant server written in C to improve performance. The new MASTER reduces was optimized and reduces queries to the database by ~90%.


MS is used by the clients to retrieve information about other online clients. The query is similar to an SQL query, with select, where and limit clauses. The reply is encrypted by a game specific secret.

At the beginning, MS was implemented as PHP, but piped the response through an encoder written in C. In January 2016, it was integrated into the MASTER server (written in C).


NATNEG is used to establish a connection between two players, both of whom are behind NAT. The clients only communicate with this server when they try to connect to another player.

NATNEG has been implemented in C. As it was the first C tool, it has an open second port to send special UDP packets for MS with the faked sender address of MASTER.


SAKE is used for data exchange — files or records can be uploaded to the SAKE server. This is used for friend Mii exchange in Mario Kart Wii, along with ghosts.

SAKE has been implemented in PHP, and can send/receive ghosts and Miis, along with other games' data.


RACE is used for downloading competitions and rankings in Mario Kart Wii. RACE has been implemented in PHP, with competition support added by Leseratte (with help from Billy), which is now fully working.


GAMESTATS is for game rankings/leaderboards. There are two versions of it; HTTP and TCP. Sepalani has implemented both in Python, the former is a near-complete implementation. Games like Mario Strikers Charged and Dr. Mario Online Rx use GAMESTATS.


DLS1 is a server for game file downloading. Wiimmfi runs a PHP version which has no files (due to copyright reasons), but a third-party DLS1 server is also ran for a lot of NDS/Wii games for their own files. This server is unused by Mario Kart Wii.

Using old profiles

For each profile, there exists a profile ID and nickname pair. Only the Wii and the server they were created on knows both of them. At login the Wii sends the nickname and the server answers with the related profile ID. If the profile ID is wrong, the game will abort the login with error code 60000.

There is only 1 way to use your old profiles with Wiimmfi: At the beginning of the project, when the old GameSpy servers were available (which shut down on July 25th, 2014), Wiimm retrieved 2.9 million pairs. If your profile was retrieved, it is possible to use your old license on Wiimmfi; otherwise, you will need to create a new friend code (Mario Kart Wii now automatically does this with the latest patch)

Details and solutions


More about Wiimmfi at this Wiki
Project forum at Wii-Homebrew.com
Forums at GBATEMP.net