Microsoft KB Archive/245646

= DNS Stops Responding to UDP Name Queries =

Article ID: 245646

Article Last Modified on 11/1/2006

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APPLIES TO


 * Microsoft Windows NT Server 4.0 Standard Edition
 * Microsoft Windows NT Server 4.0 Enterprise Edition

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This article was previously published under Q245646



SYMPTOMS
The DNS server may become silent and stop responding to name queries over User Datagram Protocol (UDP). If you restart the DNS service, the problem is resolved.



CAUSE
The DNS service runs with two UDP listener threads per processor in the server. Certain DNS queries expose a problem in a listener thread which causes the query to stop and never restart. Eventually all the UDP listener threads get into this state, after which point no more name queries can be processed by the DNS server.



RESOLUTION
A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to computers that are experiencing this specific problem.

To resolve this problem, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS

NOTE: In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

The English-language version of this fix should have the following file attributes or later:   Date        Time    Size      File name   Platform --  11/05/1999  21:42   178,448   Dns.exe     Intel 11/05/1999 21:41   299,280   Dns.exe     Alpha



STATUS
Microsoft has confirmed that this is a problem in Windows NT 4.0.



MORE INFORMATION
The listener threads actually cause an exception because of an uninitialized pointer. However, all the threads are wrapped in an exception handler which means that the offending thread is silently stopped, rather than affecting the entire server. As part of the fix to this problem, an event is now generated to indicate that an exception has occurred on a thread and that it has stopped.

Keywords: kbhotfixserver kbqfe kbbug kbfix KB245646

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