Sender Policy Framework

The idea of verifying SMTP "Envelope" MAIL FROM (see RFC2821) has a long history that goes back to 1997 with multiple people proposing this independently at various times. The first serious development of this took place in 2003 with RMX and DMP which together with other work formed the basis of SPF.

Below is a brief description of those events and documents that led to the start of SPF Project work:

Dec 14, 1997

Jim Miller sends Paul Vixie email with his idea on verifying SMTP MAIL FROM address from by means of outbound-smtp MX dns records. For more information see [1]

Note: This event and the date are not confirmed by public records and are based solely on information provided by Paul Vixie.

Mar 27, 2000 – Public mention of the idea to create 'MS' (mail sender) DNS records

Bill Cole mentions on usenet newsgroup dedicated to discussions of spam an idea to create 'MS' (Mail Sender) DNS records to record outgoing email servers of a domain.

Note: Mr. Cole later explained that this idea was mentioned in private to Paul Vixie by several other members of MAPS staff as well. Paul later wrote a draft about it (see below) crediting an idea to Jim Miller as the first person who told him about it.

June 1, 2002 – "Mail Transmitter RR" draft by David Green

David Green publishes his draft called "Mail-Transmitter RR" on namedroppers mail list (the draft specifies new dns type MT dns RR but does not say what format it would have). For more information see [2]

Note: Of interest is also that this is first public mention of the "Authorized-By" email header field which later appeared in othe IETF drafts.

June 2, 2002 – "Repudiated MAIL FROM" draft by Paul Vixie

In response to David Green's post, Paul Vixie sends to namedroppers mail list draft called "Repudiating MAIL FROM". This draft is later mentioned many times on other mail lists, sometimes with different author-entered dates varying from May to June. The last version of the draft has date of June 6 on top and May 26 in the middle of the draft and can be found on Paul's home page at [3]

Note: The email post with the draft is seen as of June 2nd for most mail list subscribers although actual Date header is June 1st as set by poster. Paul Vixie said that he wrote this draft a few weeks before and that he based it on the idea first mentioned to him by Jim Miller.

Dec 3, 2002 – First RMX draft by Hadmudt Danish

Hadmut Danisch publishes as Internet Draft the first version of RMX (A DNS RR for simple SMTP sender authentication"). The draft specifies using new DNS RR type RMX to publish either one ip4 network block or redirection to APL record. For more information on future versions and development or RMX please see Hadmudt's web page at [4]

Note: Hadmudt claims he was not aware of the either Paul Vixie's or David Green's drafts when he came up with the idea of RMX

Mar 28, 2003 – First DMP draft by Gordon Fecyk

Gordon Fecyk publishes as Internet draft the first version (version 00) of "Designated Senders Protocol". The draft proposed "DNSBL-like" format for authorizing use of RFC2821 MAIL FROM name:

As you can find in the history page describing start of SPF project in 2003, the first SPF draft looked very much like above DMP draft.