What Is Greylisting

From Roaring Penguin
Jump to: navigation, search

The way greylisting works is that when the Canit system sees an email for a valid recipient from a sender it has never seen before it sends a tempfail, try again in 1 minute, to the sending server. Any/all reputable email servers will just retry sending and the message goes through. Spammers often never retry and their messages are eventually discarded and the user never sees them.