These are the urls that have to be blocked in your router, using OpenDNS or using CCProxy:
My Wii U tried to download an update but since I had the urls blocked in my FRITZ!Box router an error for the "System Update" entry showed up in the "Download Management", so the update failed.
- Code:
nus.cdn.c.shop.nintendowifi.net
nus.cdn.shop.wii.com
nus.cdn.wup.shop.nintendo.net
nus.wup.shop.nintendo.net
nus.c.shop.nintendowifi.net
c.shop.nintendowifi.net
My Wii U tried to download an update but since I had the urls blocked in my FRITZ!Box router an error for the "System Update" entry showed up in the "Download Management", so the update failed.