Greylisting Documentation

The greylisting mechanism is controlled by options set in the spasm configuration file: Greylist, GreylistDelay, GreylistExpire, GreylistUpdate, and GreylistExpireInterval.

Setting the Greylist option (path to the greylist database) turns greylisting on. When a server connects, spasm first searches the greylist database for a matching IP address.

Summary: The first time a server connects, it must wait the amount of time specified by GreylistDelay before it is allowed to send a message. It must resend before the GreylistExpire time has passed. Upon successfully passing its first greylist delay, it will bypass greylisting for the amount of time specified by GreylistUpdate, at which point it must undergo another delay. Unlike other greylisting mechanisms, spasm only greylists by IP address. It does not use the envelope sender or envelope recipient when greylisting. This helps keep the size of the greylist database to a minimum.

Expired entries are automatically removed at intervals defined by GreylistExpireInterval.