Article ID: 197294 - Last Review: November 1, 2006 - Revision: 1.2

DNS May Return Wrong IP Address When Forwarding Query to WINS

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This article was previously published under Q197294

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SYMPTOMS

When a client queries the Microsoft DNS server for an IP address, and the DNS forwards the query to WINS, if the WINS server is busy, the DNS server may return the IP address for a different name. This will happen on an intermittent basis randomly.

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CAUSE

When the DNS sends a query to WINS, it includes a transaction ID (XID) so that it can match up responses to queries. If the DNS is busy and sending many queries to WINS, and the WINS server is busy, it is possible for the XID value to be reused by the DNS server before the WINS server returns the result for the first query using the same XID. The DNS server looks for the first matching XID in the list it was tracking, and returns the IP address in that response to the DNS client.

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RESOLUTION

The DNS now uses a larger number of unique XIDs. It also performs a check to be sure that the name returned by the WINS server matches the name queried on before returning the IP address to the requesting client.

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:

http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS (http://support.microsoft.com/default.aspx?scid=fh;en-us;cntactms)

The English version of this fix should have the following file attributes or later:

   Date      Time                  Size    File Name     Platform
   --------------------------------------------------------------
   11/17/98  02:23p               176,912  Dns.exe       (x86)
   11/17/98  02:23p               297,232  Dns.exe       (Alpha)

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