Messaging Gateway delivery retry schedule


Article ID: 159284


Updated On:


Messaging Gateway


The Symantec Messaging Gateway (SMG) is retrying to deliver a message, and the timing of the delivery attempts needs to be known.


The Symantec Messaging Gateway attempts to deliver messages immediately and failing immediate delivery, queues undeliverable messages and attempts delivery beginning at 15 minutes with an exponential back off, meaning that the delay between delivery attempts doubles with each attempt, until an upper limit of seven (7) hours is reached. Redelivery is then attempted every seven hours until the maximum queue lifetime is reached and the message is bounced.

Note: Attempting to flush a message from the delivery queue or flushing the entire queue will not reset or change the delivery attempt schedule but will artificially increment the number of delivery attempts for messages that cannot be delivered.

 The following table describes the lifetime of a message in the SMG delivery queue beginning with the initial delivery attempt at zero minutes. This table is based on the default  configuration of the SMG delivery MTA. 

Default Delivery MTA Configuration
Minimum retry interval 15 minutes
Maximum retry interval 7 hours
Sent message time-out 5 days
Bounce message time-out 1 day
Message delay time in queue before notification 4 hours



Message Delivery Schedule

0 seconds Initial delivery attempt
15 minutes First retry
45 minutes Second retry
1 hour 45 minutes Third retry
3 hours 45 minutes Fourth retry
4 hours DSN delivered to sender
7 hours 45 minutes Fifth retry
12 hours DSN delivered to sender
14 hours 45 minutes Sixth retry
21 hours 45 minutes Seventh retry
1 day 4 hours  DSN delivered to sender 
1 day 4 hours 45 minutes  Eighth retry 
1 day 11 hours 45 minutes Ninth retry 
1 day 18 hours 45 minutes Tenth retry 
1 day 20 hours DSN delivered to sender 
2 days 1 hour 45 minutes  Eleventh retry 
2 days 8 hours 45 minutes Twelfth retry 
2 days 12 hours  DSN delivered to sender 
2 days 15 hours 45 minutes Thirteenth retry 
2 days 22 hours 45 minutes Fourteenth retry 
3 days 4 hours  DSN delivered to sender
3 days 5 hours 45 minutes Fifteenth retry
3 days 12 hours 45 minutes Sixteenth retry
3 days 19 hours 45 minutes Seventeenth retry
3 days 20 hours DSN delivered to sender
4 days 2 hours 45 minutes Eighteenth retry
4 days 9 hours 45 minutes Nineteenth retry
4 days 12 hours DSN delivered to sender
4 days 16 hours 45 minutes Twentieth retry
4 days 23 hours 45 minutes Twenty-first retry
5 days Message is bounced