http://www.rfc-editor.org/rfc/rfc6591.txt
RFC 6591: Authentication Failure Reporting Using the Abuse Reporting Format, H. Fontana2012-04-01T23:00:00-00:00This memo registers an extension report type for the Abuse Reporting Format (ARF), affecting multiple registries, for use in generating receipt-time reports about messages that fail one or more email message authentication checks. [STANDARDS-TRACK]