DOCUMENT:Q162927     [winnt]
TITLE   :Telnetting to Port 53 May Crash DNS Service
PRODUCT :Microsoft Windows NT
PROD/VER:4.00
OPER/SYS:WINDOWS
KEYWORDS:kbnetwork kbbug4.00 kbfile

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The information in this article applies to:

 - Microsoft Windows NT Server version 4.0
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SYMPTOMS
========

A Windows NT 4.0 DNS server produces the following event error 454:

   DNS Server select() Function failed. The data is the error.

Besides the event error, CPU usage is high, the DNS server is unstable, and
it sometimes crashes.

CAUSE
=====

The possible cause of this problem is when an unknown user telnets to the
DNS server port 53. When this is done, and a few characters are typed, the
above behavior is seen on the Windows NT 4.0 DNS server.

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-postSP2/dns-fix

STATUS
======

Microsoft has confirmed this to be a problem in Windows NT version 4.0. A
supported fix is now available, but is not 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.

KBCategory: kbnetwork kbbug4.00 kbfile
KBSubcategory: nttcp NTSrv
Additional reference words: dns 4.00 prodnt

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