Windows 2008 Clustering validation test fails IP config

While setting up 2008 Clustering on vSphere I came across an annoying error saying that I had a duplicate IP on what seemed to be an unknown Ethernet interface.

After some poking around I managed to find a few articles that pointed me in the right direction. The problem is related to Teredo, which is an IPv6 Tunneling Protocol. It allows IPv6 communications to pass through IPv4 NATs and IPv4 servers. It ends up giving an identical IP address to its network interfaces, and that's what causes the problem.

It actually took 3 steps to get my issue to go away:

1. Disable Teredo through the command line-

Open command prompt using Run As Administrator

Type: netsh (enter)

interface (enter)

teredo (enter)

set state disabled (enter)

2. Disable Teredo through the registry

Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip6

Rightclick on the 'Parameters' tab, select 'New' and then 'DWORD'

Enter 'DisabledComponents' for the title, then double click it and select the Hexadecimal option and enter the number 8.  Click OK and restart your machine.

After this I still was having the issue, so the last thing I found that finally worked was to go to the device manager, click view and select show hidden devices, look under network adapters and then delete the Teredo network adapter and reboot.

This time it worked perfectly and everything is humming fine.

It's possible that you may be able to get the same result with only one or two of the above routes.

Onward...