DOCUMENT:Q195201  17-APR-1999  [exchange]
TITLE   :XFOR: 5.0 and 5.5 Internet Mail Services Do Not Do AUTH NTLM
PRODUCT :Microsoft Exchange
PROD/VER:WinNT:5.5
OPER/SYS:
KEYWORDS:exc55sp2fix

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The information in this article applies to:

 - Microsoft Exchange Server, version 5.5 
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SYMPTOMS
========

The Internet Mail Service cannot support an authenticated SMTP connection
between an Exchange Server 5.0 computer and an Exchange Server 5.5 computer.
When the Exchange Server 5.0 computer tries to create a secure SMTP connection
to the Exchange Server 5.5 computer, it will fail with a 502 authentication
error, and users will get the following non-delivery report (NDR):

   One or more mandatory argument(s) were missing from the recipient
   MSEXCH:IMS:POF:FDRC:NTS2 3502 (000B0981) 502 Server does not support
   AUTH.

When the Exchange Server 5.5 computer tries to create a secure SMTP connection to
the Exchange Server 5.0 computer, the version 5.0 server computer returns a 500
command not recognized response.

CAUSE
=====

Exchange Server 5.0 uses the SMTP extension XAUTH to set up NTLM authentication.
Exchange Server 5.5 uses the SMTP extension AUTH to do this. When going from
version 5.0 to 5.5, the server computer running Exchange Server 5.0 quits the
SMTP session when it does not see XAUTH in the list of extensions offered by the
computer running Exchange Server 5.5. When going from version 5.5 to 5.0, the
server computer running Exchange Server 5.5 sends an AUTH NTLM command to the
server computer running Exchange Server 5.0, which returns a 500 command not
recognized response.

RESOLUTION
==========

To resolve this problem, obtain the latest service pack for Exchange Server
version 5.5. For more information, please see the following article in the
Microsoft Knowledge Base:

   Q191014 XGEN: How to Obtain the Latest Exchange Server 5.5 Service Pack


The English version of this fix should have the following file attributes or
later:

   Component: Internet Mail Service

   File Name      Version
   -------------------------
   Msexcimc.exe   5.5.2394.0


STATUS
======

Microsoft has confirmed this to be a problem in Microsoft Exchange Server
version 5.5.

MORE INFORMATION
================

To resolve this issue, the fix only needs to be applied to the server computer
running Exchange Server version 5.5, no changes are required on the server
computer running Exchange Server version 5.0.

To install the hotfix, please perform the following step:

Copy the Msexcimc.exe file included in the hotfix to the following location:

   Exchsrvr\Connect\Msexcimc\Bin
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Keywords          : exc55sp2fix 
Technology        : kbExchangeSearch kbExchange550 kbZNotKeyword2
Version           : WinNT:5.5
Issue type        : kbbug
Solution Type     : kbfix

=============================================================================

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