IPv6 for Windows
Unlike Windows XP and Windows Server 2003, IPv6 in Windows Vista and Windows Server 2008 cannot be uninstalled. However, you can disable IPv6 in Windows Vista and Windows Server 2008 by doing one of the following:
Add the following registry DisabledComponents value (DWORD type) set to 0xFF:
This method disables IPv6 on all your LAN interfaces, connections, and tunnel interfaces but does not disable the IPv6 loopback interface. You must restart the computer for this registry value to take effect.
Alternatively copy the contents below into a file using the reg extension and then run on your server.
Windows Registry Editor Version 5.00 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip6\Parameters] "DisabledComponents"=dword:000000ff
If you disable IPv6, you will not be able to use Windows Meeting Space or any application that relies on the Windows Peer-to-Peer Networking platform or the Teredo transition technology.
If you disable either the IPv4 or the IPv6 stack after you have installed the domain name system (DNS) Server role, you will experience timeouts and delays in DNS queries.
Do not enable or disable the IPv4 or the IPv6 stack unless necessary.
If you must enable or disable either stack after installing the DNS Server role, restart the DNS Server service.
If you cannot restart the DNS Server service, manually remove the invalid forwarders for the disabled stack. For example, if the IPv6 stack is disabled, remove the IPv6 forwarders.