Not sure if this will help, but for my 360, i gave it a static local ip and did port forwarding on my router so that when my 360 connects, it forwards it to the opened ports.

I don't fully understand it myself either but it seems to work :-/

1) Find what ports you are suppose to open for Wii U.
2) Set a static local IP for your Wii U that won't be used by other devices
2) Enable port forwarding/triggering on your modem, if it ask for local IP of the device, input the static IP you set for the Wii U.

Good Luck

This post has been edited by m00ch: May 3 2014, 07:16 PM