Spam folders considered harmful

Posted Jan 7, 2010 12:46 UTC (Thu) by anselm (subscriber, #2796) [Link]

By way of clarification, I think the upstream comment meant »once the mail has entered the local queue«. It is possible to reject a message while it is being submitted, but once the local MTA has accepted responsibility for it it can only be bounced, which as has been noted will in most cases inconvenience those people whose addresses the spam claims it is being sent from.

To reject spam rather than bounce it, one needs to run anti-spam software while the message is still in the process of being read, where the more common setup is to run the anti-spam software after the message has been accepted locally but before it is delivered to the addressee's mailbox. Depending on the checks the anti-spam software performs (especially ones that access the network), pre-queue checking may be a resource-intensive process, so it requires careful configuration.