DMARC Policy and Reporting
Enforcing alignment and reading reports.
What DMARC Adds
DMARC (Domain-based Message Authentication, Reporting and Conformance) ties SPF and DKIM together and fixes their biggest blind spot.
SPF and DKIM each authenticate a domain, but not necessarily the visible From header the user sees. DMARC requires that authentication aligns with the From domain, and it tells receivers what to do when a message fails, plus it sends you reports.
The Concept of Alignment
Alignment is the heart of DMARC. A message passes DMARC only if it passes SPF or DKIM and that authenticated domain matches the visible From domain.
- SPF alignment — the envelope MAIL FROM domain matches the From domain
- DKIM alignment — the DKIM
d=domain matches the From domain
This is what stops an attacker who passes SPF for their own domain while displaying your domain in From.
All lessons in this course
- How Email Spoofing Works
- SPF Records
- DKIM Signing
- DMARC Policy and Reporting