How To Setup Milter Greylist Spam Blocking In Sendmail
Greylisting is the process by which all email (unless specifically whitelisted) gets initially rejected yet works within the parameters of the various RFCs to ensure eventual receipt of email. The idea is that spammers will not attempt to reconnect to an email server that has rejected their offerings yet legitimate mail servers will. It isn’t foolproof – spammers are quick to adjust and greylisting has been around a long time....