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

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The information in this article applies to:

 - Microsoft Windows NT Server version 4.0
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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/spa/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

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