W2K DNS Server fails on unqualified name lookup


Richard Harris


I have a W2K SP4 Server acting as both DHCP and DNS servers.
The server acts only to forward requests and maintain a local cache,
there are no local forward lookup zones.

We noticed a problem with Outlook XP displaying delay status bars, and
narrowed it down to DNS resolution.
The delay was being caused because we were appending our primary
domain suffix (UK.MYCOMPANY.COM) to an unqulified name, and this was
not being found and thus it took ages to get past DNS so WINS could
resolve the name.

Outlook requests the unqaulified name MAILSERVER1

Thus the client first queries DNS for MAILSERVER1.UK.MYCOMPANY.COM but
doesnt find it because its FQDN is as above.
DNS then steps up a level and queries MAILSERVER1.MYCOMPANY.COM but
doesn't find it here either, so then reverts to WINS where it is
eventually found.

It was taking 15 seconds to finally get to WINS, by this time Outlook
displays "delay" errors.

So to fix this problem, I decide to append domain suffixes to
unqualified names on the client.

I add them in the following order:

But here is where my DNS problem occurs!!
When the first DNS query in the list occurs (for
MAILSERVER1.UK.MYCOMPANY.COM), there is no response from the DNS
server, and the client immediately queries my secondary DNS server
(and fails). I would expect the DNS to reply with a "Name not found"
error then try the next suffix in the list, but it does not!! If I
query a server I know to be in UK.MYCOMPANY.COM, the DNS server will
respond!!!!! (note I have been deleting local cache)

Whats even stranger is that it only does this when it appends the
UK.MYCOMPANY.COM domain. If I remove it from the list the DNS server
gives me a "Name not found" for the FR.NYCOMPANY.COM then goes to "SE"
where it find the server (expected behaviour).

My DNS server is set up to just forward requests to other DNS servers
and has no responsibility for the UK domain or any other lookup zones.

The only solution I have at the moment is to relegate UK.MYCOMPANY.COM
to the bottom of the list so it is appended last assuming that the
server would be found in another domain by then, but this means all
local UK traffic is slowed down as it is last on the list.

Any suggestions why this may be happening.

William Stacey

I would use dig or nslookup to make directed queries (with that fqdn) to
that dns server and look at the replies (if any). If no replies or not
correct, then start looking at the server using netmon to see what it is
doing, what queries it sends out itself, etc. May also want to upgrade to
new sp if not already. Are you using root hints on that dns server (what
version of windows is it btw?) and/or forwarding?

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