Microsoft KB Archive/257727

= XCON: Slow Mail Flow Across X.400 Connector with 289 and 1294 Warnings =

Article ID: 257727

Article Last Modified on 10/28/2006

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APPLIES TO


 * Microsoft Exchange Server 4.0 Standard Edition
 * Microsoft Exchange Server 5.0 Standard Edition
 * Microsoft Exchange Server 5.5 Standard Edition

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This article was previously published under Q257727



SYMPTOMS
The two following error messages may be displayed:

Event ID - 289

Source - MSExchangeMTA

Description - A connection to 1% could not be opened.

Event ID -1294

Source - MSExchangeMTA

Description - An association with entity 1% ended abnormally.

Messages also intermittently back up on a message transfer agent (MTA) queue for an X.400 Connector to a remote site. When you stop and restart the MTA, mail flow resumes.



CAUSE
This issue can occur as a result of poor network quality.



WORKAROUND
To work around this issue:
 * 1) Open the X.400 Connector properties, and click the Override tab.
 * 2) Under the Request to Send (RTS) values, set Checkpoint Size to 10 (30 is the default), and Window Size to 3 (default value is 5). In the Association Parameters box, set Disconnect to 360 (default value is 120).
 * 3) Stop and restart the MTA service.

Mail flow should resume and continue.



MORE INFORMATION
Checkpoint size. Sets the amount of data to be transferred before a checkpoint is inserted. If an error occurs and the message must be retransferred, the process restarts from the most recent checkpoint. If you specify zero, no checkpoint is set. If you use a checkpoint, you slightly reduce the transmission speed. Decrease the checkpoint size when the connection is less reliable.

Window size. The number of checkpoints that can go unacknowledged before data transfer is suspended. The greater the window size, the greater the transfer rate. The window size determines the amount of resources set aside for the receiving station. Specify window size only if the checkpoint size is greater than zero.

Disconnect. The amount of time to wait before a connection is terminated because of a previously terminated association.

Additional query words: XMRP

Keywords: kbprb KB257727

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