Graylisting Mailenable

Graylisting is a technique used by a mail exchanger host to defend against spam deliveries by temporarily rejecting all mail from unrecognized sources.
When the graylisting mx rejects a message from a spammer, the spammer generally won't attempt redelivery (because he has plenty of other addresses to try, and can't be bothered with following up on rejections).
Spammers think that following smtp rules is for other people; graylisting is an elegant technique that uses their own disdain against them.
Graylisting requires a bit of extra work by the mx (particularly for large mailing services that must coordinate among many mx hosts), but possibly not as much cpu time as would be required to process and filter the spam if it were not rejected.
Graylisting can result in delays in delivery of honest mail that may be objectionable in some cases (e.
Still, many mail services are pleased with the performance of graylisting (as are, one imagines, their users).
Graylisting has spawned a couple of related techniques that also exploit the fact that spam mail senders don't follow the rules of smtp.

graylisting mailenable