Wii Network Guide

Since Dolphin 3.5-2143, Wii games running in Dolphin can now connect to the network in order to play online with other Dolphin users but also Wii users. This requires a few steps to setup: for copyright reasons, we can't distribute with Dolphin some of the files that are required to connect to the Nintendo WFC network. However, these files can be acquired from an official source by following this guide.

Limitations

 * This is still basically a beta: a few games work (Monster Hunter Tri, Mario Kart Wii, Super Smash Bros Brawl), others don't. In doubt, test it.
 * Friend codes do not always work.
 * Buying and downloading DLC requires you to have a NAND dump and a keys.bin dump from your real Wii.

Getting the Wii operating system files
Download the NUS Downloader application, extract the ZIP archive, and launch the NUS Downloader application. Check the "Keep Encrypted Contents" box, then use the menu to select the latest version of IOS 13. Click the "Start NUS Download" button to download the Wii operating system files from Nintendo.



Wait until the download is finished, then go to the directory where you extracted NUS Downloader. From there, browse to the "titles\000000010000000D\1032" directory and check that the 00000011.app file exists. It will be required for the next step.

Extracting the certificates from the operating system
Download the extract_certs.exe program. Drag and drop the 00000011.app you got from NUS Downloader on this program, and you should see three files appear next to 0000001.app: clientca.pem, clientcakey.pem and rootca.pem.

If you are using Linux or OSX, compile extract_certs.cpp (in C++11 mode) and use this to dump the certificates.

Copying the certificates to your Dolphin folder
Copy these three PEM files to the User\Wii directory in your Dolphin folder. After this is done, you should be able to access online games with Dolphin! Enjoy.