DOCUMENT:Q197294 20-MAY-2002 [winnt] TITLE :DNS May Return Wrong IP Address When Forwarding Query to WINS PRODUCT :Microsoft Windows NT PROD/VER:WinNT:4.0 OPER/SYS: KEYWORDS: ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows NT Workstation version 4.0 - Microsoft Windows NT Server version 4.0 ------------------------------------------------------------------------------- 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. 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. 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 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) STATUS ====== Microsoft has confirmed this to be a problem in Windows NT version 4.0. Additional query words: 4.00 ====================================================================== Keywords : Technology : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT400search kbWinNTSsearch kbWinNTS400search kbWinNTS400 Version : WinNT:4.0 Hardware : ALPHA x86 Issue type : kbbug Solution Type : kbfix ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 2002.