DOCUMENT:Q169781  30-AUG-2001  [exchange]
TITLE   :XFOR: IMC Fails to Send Mail to Domains with Multiple MX Records
PRODUCT :Microsoft Exchange
PROD/VER:WinNT:4.0,5,0
OPER/SYS:
KEYWORDS:kbusage

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The information in this article applies to:

 - Microsoft Exchange Server, versions 4.0, 5.0 
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IMPORTANT: This article contains information about editing the registry.
Before you edit the registry, make sure you understand how to restore it
if a problem occurs. For information on how to do this, view the "Restoring
the Registry" online Help topic in Regedit.exe or the "Restoring a Registry
Key" online Help topic in Regedt32.exe.

SYMPTOMS
========

This problem occurs when you send SMTP messages through the Internet Mail
Service (or the Internet Mail Connector [IMC], in version 4.0) to domains with
multiple MX records. The message stays in the outbound queue waiting delivery,
gets name resolution, and then times out, and a non-delivery report (NDR) is
returned. This problem is usually encountered when sending messages to large
corporations.

The following error message may be received when you get information on the
messages sitting in the queue:

   421 NSO hq.com Unable to contact destination SMTP demon nestle.com

WORKAROUND
==========

To work around this problem:

WARNING: Using Registry Editor incorrectly can cause serious problems that may
require you to reinstall Windows. Microsoft cannot guarantee that problems
resulting from the incorrect use of Registry Editor can be solved. Use Registry
Editor at your own risk.

For information about how to edit the registry, view the "Changing Keys And
Values" online Help topic in Registry Editor (Regedit.exe) or the "Add and
Delete Information in the Registry" and "Edit Registry Data" online Help topics
in Regedt32.exe. Note that you should back up the registry before you edit it.

1. Add DisableResolverSearchList to the following registry key:

      HKEY_LOCAL_MACHINE\System\CCS\Services
      \MSExchangeIMC\parameters

   DisableResolverSearchList is added in the

   For more details on this process refer to Q150969.

2. Use NSLookup to get the correct IP addresses for the correct MX records of
   each E-Mail Domain.

3. In the IMC \ IMS Connections property tab, click on the E-Mail Domain command
   to specify Message Delivery by E-Mail domain.

4. Enter one Domain name- IP address pairs for every MX record found in step 2.

5. Repeat steps 3 and 4 for every other domain that has having multiple
   MXrecords and is experiencing this problem.

6. Send a message to each one of these domains to test the workaround solution.


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Keywords          : kbusage 
Technology        : kbExchangeSearch kbExchange500 kbExchange400 kbZNotKeyword2
Version           : WinNT:4.0,5,0
Issue type        : kbprb

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