When mail in the queue is undeliverable, Postfix will log why, and
will create a bounce message, and will remove the undeliverable
message.
When the bounce message is undeliverable, Postfix will log why, and
will create a 'double bounce' message, and will remove the bounce
message.
When the 'double bounce' is undeliverable, Postfix will log why,
and will remove the 'double bounce' message.
This process stops after three steps, to avoid an infinite loop or
even an email explosion. What explosion? Each of the above steps
may result in one message being sent to an alias with multiple
recipients. That explosion.
The above process is documented with copious logging. My definition
of 'silent' differs from yours.
For testing, 'dont_remove = yes' will keep removed mail, but it has
poor usability, as the operator gets to read everyone's email.
Wietse
