On 5/23/2011 10:59 AM, yaoxing wrote:
I fixed the issue you mentioned above. Now it seems all the stuck mails had went to the deferred queue, and the active queue is clear again. This is interesting. I checked some mail in the deferred queue. Most of them seems to be "Undelivered Mail Returned to Sender". It seems someones sent mails to our no-reply mailbox. And this mailbox itself doesn't exist. So our server generate a bounce mail, while this mail is denied by the their mail servers. They stuck in the active queue. Could be some kind of attack?
Don't accept mail that you can't or won't deliver. Generating bounces will clog up your queues with undeliverable mail, slowing down legit delivery. Send too many bounces and eventually your server will be blacklisted.
http://www.postfix.org/LOCAL_RECIPIENT_README.html http://www.postfix.org/ADDRESS_CLASS_README.html -- Noel Jones
