DOCUMENT:Q154984    [winnt]
TITLE: DNS Server May Not Recursively Resolve Some Names
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
========

Your Domain Name System (DNS) server does not recursively resolve names
which contain a large number of IP addresses. However, the DNS server does
resolve names which contain one or a small number of IP addresses.

CAUSE
=====

When a DNS response contains more data than can fit in a UPD packet (more
than 512 bytes,) it sends as much data that can fit into the UDP packet and
sets the truncation bit, indicating that there is more data available.

The Microsoft DNS server discards packets with the truncation bit set and
tries another authoritative server. The DNS server always receives the same
response with the truncation bit set, so it eventually stops and returns
SERVFAIL to the client.

RESOLUTION
==========

The Microsoft DNS Server has been modified to accept truncated responses
and return that response to the client.

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/chp/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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