I'm hoping someone knows the key to this.
I use a backup MX service to accompany my Postfix mail server. Right now
the Backup MX service has more than 1,200 messages waiting to be
delivered. As near as I can tell (from the Postfix logs) all of them are
addressed to addresses that either never existed or no longer exist. The
Postfix log indicates it is bouncing them with a 450 (temporary bounce)
instead of a 550. So the Backup MX service is keeping them and
continually trying to re-send.
I've checked the main.cf. The following two lines are as listed in the file:
unknown_local_recipient_reject_code = 550
soft_bounce = no
To complicate things further, when I sent a test message to an invalid
address, I quickly get a 550 response. It appears it's giving 450
responses to some senders and 550 responses to others, even when the
same invalid address is used.
Thanks for any assistance.
