Windows 2008 doing AAAA record lookups as well as A lookups

Peter Lawton · Guest

When doing a DNS lookup from a Windows 2008 box it does a normal A record
lookup first then it does an AAAA record lookup, even when IPv6 isn't
enabled, doubling the name lookups the machine does for no good purpose and
doubling the load on the DNS servers.

The only reference I can find on the MS site is for Vista, but implies that
this shouldn't be happening

http://technet.microsoft.com/en-us/library/bb727035.aspx :-

"The DNS Client service in Windows Vista has been designed to minimize the
impact on DNS servers when performing DNS name queries through the following
behavior:
If the host has only link-local or Teredo IPv6 addresses assigned, the DNS
Client service sends a single query for A records.
If the host has at least one IPv6 address assigned that is not a link-local
or Treed address, the DNS Client service sends a DNS query for A records and
then a separate DNS query to the same DNS server for AAAA records. If an A
record query times out or has an error (other than name not found), the
corresponding AAAA record query is not sent."

I've unbound IPv6 from all adapters and added the registry entry
"HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip6\Parameters\Disabled
Components" value off to disable IPv6 completely.

The same behavior seems to happen on both Windows 2008 server and Vista with
SP1

Does anyone know how to stop these unnecessary AAAA lookups?

Thanks

Peter Lawton