Indeed, in more detail (which I omitted for simplicity), these checks are performed in a series of headers, the last of which is the From: header. I think the “envelope-from” is either the first or the second in this 5-point list. That said, there are a lot of implementations out there that do not respect that and treat the From address as the sender whose honesty must be verified. Every time I send mail to a mailing list from my own domain, due to DMARC I get back several reports of SPF and DKIM fail, mainly because the mailing list messed up something.
On 29 Mar 2017, at 18:32, William Herrin <bill@herrin.us> wrote:
On Wed, Mar 29, 2017 at 11:25 AM, Grant Taylor via NANOG <nanog@nanog.org> wrote:
Every SPF implementation I've seen has checked the SMTP envelope FROM address /and/ the RFC 822 From: header address.
Hi Grant,
The gold standard, Spamassassin, does not. Indeed, the message to which I reply was scored by spam assassin as "SPF_PASS" even though you do not include NANOG's servers in the SPF record for tnetconsulting.net.
Regards, Bill Herrin
-- William Herrin ................ herrin@dirtside.com bill@herrin.us Dirtside Systems ......... Web: <http://www.dirtside.com/>