Q119884: PC Ext: Increasing Retry Count for LAN-Based Mail
Article: Q119884
Product(s): Microsoft Mail For PC Networks
Version(s): WINDOWS:3.0,3.2,3.2a,3.5
Operating System(s):
Keyword(s):
Last Modified: 29-OCT-1999
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The information in this article applies to:
- Microsoft Mail for PC Networks, versions 3.0, 3.2, 3.2a, 3.5
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SUMMARY
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It is possible to set retries for each external postoffice defined on a network.
This might be desirable when frequent "retry count exceeded" messages are
displayed in the SYSTEM.LOG file. The ADMIN.EXE program directly supports
setting the retries for postoffices with routing defined as Direct via Modem.
Once this count has been set, it is retained when the postoffice routing is
modified to Direct via MS-DOS drive.
To set the retry count for mail destined to a specific postoffice:
1. Run ADMIN.EXE at the postoffice that is the source of the mail.
2. Select External-Admin, Modify and choose the destination network name and
postoffice.
3. Specify routing to be Direct via Modem.
4. Answer yes to the Modify? prompt.
5. Select External-Admin, Setup and press <ENTER> at the network name.
6. Select the Options and Retries menu item.
7. Enter the desired number of Retries for the postoffice. Escape back and
select Yes to update the record.
8. Select External-Admin, Modify and change the routing of this postoffice back
to its former routing, such as Direct via MS-DOS Drive.
9. Answer yes to modify the postoffice.
This will have reset the count in the XTN file.
NOTE: This change does not immediately become effective. The External program,
which makes use of this count, caches this information in memory and will not
have the new value until it updates from the postoffice.
Updating occurs when External starts and when the update interval is reached. The
update interval is normally five minutes, but it can be set to a different value
through command line and INI settings using the IntervalUpdate= parameter. See
Chapter 12 of the "Administrator's Guide" for more information on External
parameters.
MORE INFORMATION
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How the Retry Count is Used
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External will cycle through the queues of external postoffices looking for mail
to be dispatched. If mail is to be transferred and an attempt to deliver this
mail is unsuccessful, External will update the queue to reflect that an
additional retry occurred. Each time an error occurs on a specific mail item,
its retry count is incremented. After incrementing, the number is compared to
the maximum retry count associated with the destination postoffice. If the
number is equal to or exceeds the retry count, the mail is considered
undeliverable and will be returned to the originator.
The default retry count for a mail item is 3. This means that after 3 attempts,
the item is returned and the following message is placed into the SYSTEM.LOG:
[005] Mail Retry count exceeded sending to: ...
How Changing the Retry Count Effects Mail Delivery
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When there is only one MTA (External) processing mail at a postoffice, the span
of time before a mail item is returned would generally be about 15 minutes. This
is based on a retry count of 3 and an interval of 5 minutes between MTA cycles.
If External cannot make a full cycle of all postoffices in 5 minutes, the total
time could be longer. This 15 minutes might be long enough for temporary network
problems to be eliminated and for the item to successfully transfer.
When multiple MTAs operate in a mail configuration, the span of time before the
retry count is exceeded is difficult to predict. Consider a situation in which
three MTAs operate. It is possible that one MTA would have just finished
updating the retry count for a mail item and another MTA would make another
attempt. If all three MTAs were close behind one another, then the default retry
count could be exceeded in a matter of a few minutes. In this case, updating the
retry count could provide a needed time buffer.
The best scenario is one in which the network, routers, and servers rarely fail.
If at all possible, steps should be taken to remedy problems in these areas
rather than have excessive retries.
The Retry Count Effects Notification of Mail Problems
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If External is persistent (high retry count) in its attempt to deliver mail, mail
can sit in queues for a long time before the sender is notified that there is a
delivery problem. As explained above, this is dependent on the number of MTAs
operating and the cycle interval.
NOTE: Until the retry count is exceeded, the sender has no indication that there
are delivery problems. For the known unreliable network connections, the
administrator is faced with the task of balancing the competing priorities of
persistent mail delivery vs. the senders need to know that his mail has not yet
been delivered.
Additional query words: 3.00 3.20 3.20a 3.50
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Keywords :
Technology : kbMailSearch kbZNotKeyword3 kbMailPCN320 kbMailPCN320a kbMailPCN300 kbMailPCN350
Version : WINDOWS:3.0,3.2,3.2a,3.5
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