DOCUMENT:Q198563  16-JAN-1999  [exchange]
TITLE   :XFOR: Replies to Some Internet Mail Messages Fail
PRODUCT :Microsoft Exchange
PROD/VER:winnt:5.0,5.5
OPER/SYS:
KEYWORDS:

======================================================================
-------------------------------------------------------------------------------
The information in this article applies to:

 - Microsoft Exchange Server, versions 5.0, 5.5 
-------------------------------------------------------------------------------

SYMPTOMS
========

When an Exchange Server recipient replies to some Internet messages, he or she
may receive a non-delivery report (NDR) indicating an invalid domain name. The
original in-bound message the recipient received from the Internet contains a
sender with an address similar to the following:

   <user@correct.domain.com>@incorrect.domain.com

In this example, "@incorrect.domain.com" is a non-existent domain name that has
been appended to the correct address, "user@correct.domain.com." The domain
"@correct.domain.com" is the valid domain name.

These additional domain name or names cause the message not be delivered. The
additional domain names may be added to the sender's address as a result of some
foreign mail configurations.

CAUSE
=====

In Internet Mail Service outbound mail, the domain name is found by looking for
the last @ sign in the address. In this case this is "@incorrect.domain.com."


The Internet Mail Service tries to resolve "incorrect.domain.com," which does not
exist, and fails. Thus, the message gets returned to the Exchange Server sender
as an NDR.

Now, on the way into the information store from the Internet Mail Service, the
address is checked to make sure it is usable. The check looks for the < and
> symbols, and clears out everything else except what is inside these
symbols. As a result, the message is cleaned up, and resent.

WORKAROUND
==========

The Exchange Server sender should resend the message from the NDR; it will
work.


Additional query words: reply double dual domains smtp mail fail duplicate

======================================================================
Keywords          :  
Technology        : kbExchangeSearch kbExchange500 kbExchange550 kbZNotKeyword2
Version           : winnt:5.0,5.5
Issue type        : kbprb

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

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS
PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND.  MICROSOFT DISCLAIMS
ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  IN NO
EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR
ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL,
CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF
MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.  SOME STATES DO NOT ALLOW THE EXCLUSION
OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES
SO THE FOREGOING LIMITATION MAY NOT APPLY.

Copyright Microsoft Corporation 1999.