"This memo updates the definition of the Sieve mail filtering language ""reject"" extension@ originally defined in RFC 3028. A ""Joe-job"" is a spam run forged to appear as though it came from an innocent party@ who is then generally flooded by automated bounces@ Message Disposition Notifications (MDNs)@ and personal messages with complaints. The original Sieve ""reject"" action defined in RFC 3028 required use of MDNs for rejecting messages@ thus contributing to the flood of Joe-job spam to victims of Joe-jobs. This memo updates the definition of the ""reject"" action to allow messages to be refused during the SMTP transaction@ and defines the ""ereject"" action to require messages to be refused during the SMTP transaction@ if possible. The ""ereject"" action is intended to replace the ""reject"" action wherever possible. The ""ereject"" action is similar to ""reject""@ but will always favor protocol-level message rejection."