Caching-Only DNS Server Incorrectly Reports "Name Error" on Wildcard MX Lookups (192407)
The information in this article applies to:
- Microsoft Windows NT Workstation 4.0
- Microsoft Windows NT Server 4.0
This article was previously published under Q192407 SYMPTOMS
A caching-only DNS server incorrectly returns a "Name Error" message when
looking up a wildcard MX record. This occurs when another computer has
recently looked up an "A" record with the same node name, and the "A"
record is nonexistent. The record is held in cache on the caching-only
server, and marked as Name Error. Future wildcard "MX" record lookups for
the node name return Name Error until the cache is flushed on the caching-
only DNS server.
Some UNIX mail servers query for a type "A" host name before querying for
an "MX" record and, therefore, may not be able to properly deliver mail
when Name Error is returned.
CAUSE
When the initial type "A" lookup is performed, the authoritative server
replies with a "Name Error" message. The caching-only name server responds
correctly by keeping this Name Error information in cache so that
additional lookups do not require additional referrals from the
authoritative DNS Server. When the wildcard "MX" request is received
following the type "A" lookup, the caching server reads from cache and
returns "Name Error" for the node.
Only in the wildcard MX record case, where the "A" record would be
nonexistent while the MX record would be resolvable, would an incorrect
error be generated.
RESOLUTION
A supported fix that corrects this problem is now available from Microsoft,
but has not been fully regression tested and should be applied only to
systems experiencing this specific problem. If you are not severely
affected by this specific problem, Microsoft recommends that you wait for
the next Windows NT service pack that contains this fix.
To resolve this problem immediately, contact Microsoft Product Support
Services to obtain the fix. For a complete list of Microsoft Product
Support Services phone numbers and information on support costs, please go
to the following address on the World Wide Web:
The English version of this fix should have the following file attributes
or later:
Date Time Size File Name Platform
-------------------------------------------------------------
08/22/98 12:48p 176,912 Dns.exe (x86)
08/22/98 01:04p 65,808 Nslookup.exe (x86)
08/22/98 12:47p 297,744 Dns.exe (Alpha)
08/22/98 01:02p 93,456 Nslookup.exe (Alpha)
With the above fix, the authoritative name server responds to a query for a
nonexistent hostname with error code 0. The caching-only server does not
cache the name with error code 0, "No Error."
Please note that Dns.exe must be replaced on the authoritative server.
STATUS
Microsoft has confirmed this to be a problem in Windows NT version 4.0.
| Modification Type: | Minor | Last Reviewed: | 9/23/2005 |
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| Keywords: | kbHotfixServer kbQFE kbbug kbfix kbQFE KB192407 |
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