DOCUMENT:Q142047 [winnt] TITLE: Bad Network Packet May Cause Access Violation (AV) on DNS Server PRODUCT: Microsoft Windows NT PROD/VER:4.00 OPER/SYS:WINDOWS KEYWORDS:kbbug4.00 kbnetwork NTSrv nttcp -------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows NT Server version 4.0 -------------------------------------------------------------------------- SYMPTOMS ======== The Domain Name System (DNS) fails with an access violation and ceases to resolve names. CAUSE ===== If a DNS query is modified so that the original query's AnswerCount field is greater than 0, the DNS server may cause an access violation (AV). If the AnswerCount is greater than 0, we expect to already have data from the original query, but in this case, the data is not present. RESOLUTION ========== Obtain the following fix or wait for the next Windows NT service pack. This hotfix has been posted to the following Internet location: ftp://ftp.microsoft.com/bussys/winnt/winnt-public/fixes/usa/NT40/ hotfixes-postSP3/dns-fix STATUS ====== Microsoft has confirmed this to be a problem in Windows NT version 4.0. A supported fix is now available, but has not been fully regression-tested and should be applied only to systems experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft recommends that you wait for the next Service Pack that contains this fix. Contact Microsoft Technical Support for more information. Additional query words: 4.00 prodnt ============================================================================ 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.