Although its intended use is DKIM, VBR
http://en.wikipedia.org/wiki/Vouch_by_Reference allows SPF as a means
to identify that a mail message originates from a given domain. In the
draft's words:
When SPF is the validation mechanism, VBR's md= MUST be the same
value as the domain name in the <reverse-path> address that is the
first parameter to the SMTP MAIL command.
A domain is valid for use with VBR only when the SPF process
produces a "pass" result.
Briefly, VBR provides for a list (mv=) of certifiers, i.e. third
parties offering vouch-for services. If example.net is one such
operator, a DNS record like
example.com._vouch.example.net. IN TXT "all"
would certify all mail from example.com. In that case headers like
Return-Path: <someone(_at_)example(_dot_)com>
Received-SPF: pass SPF=MAILFROM;
...
VBR-Info: md=example.com; mc=transaction;
mv=example.net:another.example;
will validate the message, if the recipient trusts example.net.
-------------------------------------------
Sender Policy Framework: http://www.openspf.org
Modify Your Subscription: http://www.listbox.com/member/
Archives: https://www.listbox.com/member/archive/735/=now
RSS Feed: https://www.listbox.com/member/archive/rss/735/
Powered by Listbox: http://www.listbox.com