DOCUMENT:Q262124  06-AUG-2002  [exchange]
TITLE   :XCON: Message Loop to SMTP Custom Recipient Over X.400 Connector
PRODUCT :Microsoft Exchange
PROD/VER:winnt:5.5
OPER/SYS:
KEYWORDS:exc55

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The information in this article applies to:

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

In a system that has the following setup

 - Site A:

    - Site address on Internet Mail Service *

    - Site addressing on X.400 Connector

    - X.400 (Site B address space)

 - Site B (No directory replication):

    - Site addressing on X.400 Connector

    - X.400 (Site A address space) and Simple Mail Transfer Protocol (SMTP) *

if any user in Site B sends SMTP one-off e-mail, the e-mail is delivered with no
problems by using the following format:

   <user>@<domain>.com

NOTE: * is a variable for the SMTP address that the SMTP messages use to route
the message.

However, if a user in Site B sends e-mail to an SMTP custom recipient, the e-mail
may loop between the bridgehead servers and finally return with the following
non-delivery report (NDR):

   The following recipient(s) could not be reached: c=US;a=
   ;p=Carlson;o=naTGIF01-Corporate;s=Test2;g=Jim; on 4/7/00 1:11 PM Either the
   message size exceeds the maximum allowed for the recipient or transport, or
   you have exceeded the storage limit on your mailbox. The MTS-ID of the
   original message is: c=US;a= ;p=Carlson;l=CRWCEXG1-000407175815Z-852143
   MSEXCH:MSExchangeMTA:naCORP-Connector:OTCMSG05

CAUSE
=====

This issue can occur because the message transfer agent (MTA) routes custom
recipients differently than one-off addresses.


The custom recipient uses the X.400 proxy of the custom recipient, so it has a
full X.400 address and not just the Site-Proxy-Space of Site B. The MTA performs
a directory lookup for the SMTP address. The MTA finds the mailbox but the
mailbox has a different X.400 address. The MTA then routes the message by using
the X.400 proxy.

The MTA routes the message back to the originating site (Site B) because of the
X.400 address space on that mailbox. That message is then resolved to the custom
recipient, which reroutes the message back to the site by using the custom
recipient default SMTP address. The message continues to loop until the message
header runs out of space (approximately 512 times).

RESOLUTION
==========

To resolve this issue, use X.400 as the default e-mail address.

WORKAROUND
==========

To work around this issue:

 - Create a directory replication connector between the two sites.

-or-

 - Create another custom recipient on the remote site.

   NOTE: This method only works for non-mailbox resolvable addresses.

Additional query words: CR

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Keywords          : exc55 
Technology        : kbExchangeSearch kbExchange550 kbZNotKeyword2
Version           : winnt:5.5
Issue type        : kbprb

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