Postfix calls this rate limiting. Here are the default values (which do not need to be present in /etc/postfix/main.cf unless you want to change them):
queue_run_delay (default: 1000 seconds) How often the queue manager scans the queue for deferred mail. maximal_queue_lifetime (default: 5 days) How long a message stays in the queue before it is sent back as undeliverable. minimal_backoff_time (default: 1000 seconds) The minimal amount of time a message won't be looked at, and the minimal amount of time to stay away from a "dead" destination. maximal_backoff_time (default: 4000 seconds) The maximal amount of time a message won't be looked at after a delivery failure. qmgr_message_recipient_limit (default: 1000) The size of many in-memory queue manager data structures. Among others, this parameter limits the size of the short-term, in-memory "dead" list. Destinations that don't fit the list are not added. |