KnowledgeBase Archive

An Archive of Early Microsoft KnowledgeBase Articles

View on GitHub

Q157630: XCON: Adjustment of Connection Retry Values on Override Tab

Article: Q157630
Product(s): Microsoft Exchange
Version(s): winnt:4.0,5.0,5.5
Operating System(s): 
Keyword(s): exc4 exc5 exc55
Last Modified: 13-JAN-2000

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

- Microsoft Exchange Server, versions 4.0, 5.0, 5.5 
-------------------------------------------------------------------------------

SUMMARY
=======

In network environments where connectivity is inconsistent and/or unreliable,
the MSExchangeMTA may routinely log X.400 Service errors in the Windows NT Event
Viewer Application log if mail is queued up to an X.400 Connector that cannot
successfully connect to the computer specified on the X.400 Connector's Stack
tab in the Microsoft Exchange Administrator program.

If the Microsoft Exchange Message Transfer Agent (MTA) is unable to make the
connection to the remote computer due to network problems, it is designed to
continue to retry every 600 seconds, by default, until a specified number of
retries has been reached (144, by default). Eventually, the MTA will generate a
Non-Delivery Report (NDR) to the originator of the message and cease attempts to
deliver to the remote computer.

Based on the Microsoft Exchange administrator's needs, these defaults may be set
differently on each X.400 Connector, depending on the reliability of the network
link between the local and remote computers.

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

The following series of Event Viewer errors may indicate that networking
problems are contributing to the MTA's inability to deliver mail across the
X.400 Connector:

  Warning Event ID 1294 Source: MSExchangeMTA Category: X.400 Service:

  An association with entity
  /O=orgname/OU=site/CN=Configuration/CN=Connections/CN=X400ConnectorName ended
  abnormally.

  Warning Event ID 4284 Source: MSExchangeMTA Category: X.400 Service:

  An error occurred during connection/disconnection. Error code: 8511.

  Warning Event ID 289 Source: MSExchangeMTA Category: X.400 Service:

  A connection to
  /O=orgname/OU=site/CN=Configuration/CN=Connections/CN=X400ConnectorName could
  not be opened.

  Information Event ID 301 Source: MSExchangeMTA Category: X.400 Service:

  An open retry delay timer started on the association to
  /O=orgname/OU=site/CN=Configuration/CN=Connections/CN=X400ConnectorName on
  control block <##>. Another attempt to reopen the association will be
  made in 600 seconds."

Also, the NDR that is generated may appear as follows:

  >----------
  >From:   System Administrator
  >Sent:   Friday, September 27, 1996 12:53 PM
  >Subject:   Undeliverable: Exchange 4.5
  >
  >Your message did not reach some or all of the intended recipients.
  >
  >      Subject:   Exchange 4.5
  >      Sent:   9/27/96 12:51:32 PM
  >
  >The following recipient(s) could not be reached:
  >
  >      David Honis on 9/27/96 12:53:24 PM
  >            The recipient could not be processed due to congestion in
  >            the message transfer service
  >*  MSEXCH:MSExchangeMTA:SiteName:ServerName

The administrator can change the Connection Retry options (these definitions are
taken from the Online Help, F1, on the Override tab) on the Override tab of the
affected X.400 Connector:

1. Max Open Retries controls the maximum number of times that the system
  attempts to open a connection before it sends a NDR (default is 144).
  Increasing this value will allow NDRs to be delayed (total time delay in sec
  = Max Open Retries X Open Interval) when there are known network problems
  that will be corrected.

2. Max Transfer Retries controls the number of times that the system tries to
  transfer a message across an open connection (default is 2). Increasing this
  value will also delay the amount of time before the MTA gives up on delivery
  and generates an NDR.

3. Open Interval (sec) controls the amount of time to wait before attempting to
  reopen a connection after an error (default is 600).

4. Transfer Interval (sec) controls the amount of time to wait before resending
  a message across an open connection after a previous attempt failed (default
  is 120).

An Example Showing How All Of These Settings May Be Used
--------------------------------------------------------

1. Assume MTA1Machine successfully makes connection to MTA2Machine after mail is
  queued up to the X.400 Connector going to MTA2 on MTA2Machine.

2. MTA1 unsuccessfully attempts to send the message over the open connection
  every Transfer Interval seconds until Max Transfer Retries is reached.

3. MTA1Machine waits Open Interval seconds before re-attempting to open the
  connection and fails to make the connection.

4. The MTA1Machine continues to wait Open Interval seconds between attempts to
  reconnect and finally generates an NDR after Max Open Retries attempts.

As can be seen from the above example, the amount of time before an NDR is
generated is dependent on all of these variables. With the default values on the
MTA, an NDR will be generated after 24 hours (144 attempts times 600 seconds is
86,400 seconds, which is 24 hours) assuming the connection failed 144 times. If
the connections are intermittently dropping, this calculation becomes less
predictable.

Additional query words: Override

======================================================================
Keywords          : exc4 exc5 exc55 
Technology        : kbExchangeSearch kbExchange500 kbExchange550 kbExchange400 kbZNotKeyword2
Version           : winnt:4.0,5.0,5.5
Issue type        : kbhowto

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

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.