Reverse MX/Bibliography

Reverse MX drafts
RMX was developed and published as drafts with the Title "A DNS RR for simple SMTP sender authentication" at the IETF. IETF drafts expire after 6 months. Although the IETF published all similar and related proposals derived from RMX as permanent RFCs for historical reasons, the IETF refused to accept RMX itself as an RFC for unknown reasons (thus breaking its own citation rules since the derived permanent RFCs cite the non-permanent RMX draft).


 * RMX Version 0, Dec 2002
 * RMX Version 1, Apr 2003
 * RMX Version 2, Jun 2003
 * RMX Version 3, Oct 2003
 * RMX Version 4, May 2004

Although DNS can be updated dynamically, the RMX records are of static nature, and the owner of the DNS domain usually does not get knowledge of the queries, which could reveal abuse of a domain name by a third party. Therefore an extension to RMX was drafted that substitutes the DNS record with a HTTP query, allowing the domain owner to use any arbitrary algorithm to authorize use of a domain name for any purpose, and to register where it has been used:


 * SCAF - Simple Caller Authorization Framework, Jan 2004

Derived and related proposals
These RFCs have been published by the IETF for historical reasons in April 2006:


 * RFC 4405: SMTP Service Extension for Indicating the Responsible Submitter of an E-Mail Message
 * RFC 4406: Sender ID: Authenticating E-Mail
 * RFC 4407: Purported Responsible Address in E-Mail Messages
 * RFC 4408: Sender Policy Framework (SPF) for Authorizing Use of Domains in E-Mail, Version 1