Comment Re:Oblig. (Score 1) 410
I can also confirm this behavior. Many sites have less anti-spam protection on their secondary (or tertiary, even), using it only to queue mail in the event that the primary is unreachable. Because it will likely accept mail without question, the secondary is the obvious target. Dump all the mail on to it as quickly as possible, and let it flounder about with struggling to deliver it, or bounce it, or double bounce it, and so on. Forcing spammers to deliver to the secondary by making the primary unreachable (making the secondary, in fact, the primary), will only slow the overall delivery of mail and make an already unmanageable situation even more convoluted.