Wii Network Guide

Since the merger of the Wii-Network branch in 3.5-2143, Dolphin can now use the Nintendo WiFi Connection to play Wii games online. Since it uses the official Nintendo platform for Wii online gameplay, Dolphin users can play online with not only other Dolphin players, but with real Wii players as well. For copyright reasons, some of the files required to access the Nintendo WiFi Connection cannot be distributed with Dolphin and have to be obtained by the user.

Limitations

 * Versions prior to [4.0-1019 https://dolphin-emu.org/download/dev/ea34ae0a70246894268b968bff91ce2f87df35c2/] use a common MAC address that has been banned. For versions prior to 4.0-1019, you can only connect to the WFC if you use a NAND Dump from your real Wii. Versions 4.0-1019 and later work normally.
 * 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 NUS Downloader. This program allows you to obtain various system files directly from Nintendo's official servers. Extract the archive then run the program. Check the "Create Decrypted Contents(*.app)" box, then select the latest version of ISO 13 by clicking Database > IOS > 000000010000000D - IOS13 > Latest Version. Click the "Start NUS Download!" button to download the Wii operating system files from Nintendo.



Once the download has completed, go to the directory where you extracted NUS Downloader and browse to the titles\000000010000000D\1032 directory. Make sure that the 00000011.app file exists; you'll need it for the next step.

Extracting the certificates from the IOS file
Download the extract_certs.exe program. Drag and drop the 00000011.app you got from NUS Downloader onto the .exe for the 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 My Documents\Dolphin Emulator\Wii directory. After this is done, you should be able to access the Nintendo WiFi Connection with Dolphin! Enjoy.