How can SPF/DKIM pass, and yet DMARC fail?

DMARC introduces the concept of "Identifier Alignment" to the world of email.  The concept is needed as SPF and DKIM are stand-alone technologies capable of associating a domain with a piece of email. When a receiver uses SPF, the receiver looks at the domain found in the RFC5321.MailFrom to figure out where to look for an SPF record.  The RFC5321.MailFrom address is the entity that is passed along as part of the "MAIL FROM" command during the SMTP conversation.  To…
dmarcian
12 October 2015