Disabling IPv6 in Windows Vista
The Internet Protocol version 6 (IPv6) has been around for over 10 years now. However, IPv4 is used much more often. Vista was the first Windows version to even have IPv6 preinstalled.
If you’re a resource freak and want the best possible performance, you might think about disabling IPv6. You can uncheck the protocol on the network connection properties dialog, but to disable it completely and for more control you must do a registry edit:
Key Location: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip6\Parameters\ DisabledComponents
If it doesn’t exist, create the key using the DWORD (32-bit) Value.
Key value depends upon what you want to do:
0: enables all IPv6 components.
0xffffffff: disables all IPv6 components, except the loopback interface. Also tells Vista to use IPv4 by default.
0x20: uses IPv4 instead of IPv6 in prefix policies.
0x10: disables native IPv6 interfaces.
0x01: disables all tunnel IPv6 interfaces.
0x11: disables all IPv6 interfaces except for the IPv6 loopback interface.