Definition
DMARC alignment
DMARC alignment is the rule requiring that the domain which passed SPF or DKIM be the same domain your recipient is shown in the From field; without it, a fraudster would pass both checks on their own domain while displaying yours.
A message carries two sender addresses. The Envelope-From is used for transport and is what SPF checks; the Header-From is what the mail client displays. They are allowed to differ, and that gap is precisely where impersonation lives.
Two tags set the severity: aspf for SPF and adkim for DKIM. In relaxed mode (r, the default) a subdomain is enough to align: invoices.example.com aligns with example.com. In strict mode (s) the two domains must be identical, which closes the door on forgotten subdomains.
- Also known as
- alignment, adkim, aspf, identifier alignment, relaxed alignment, strict alignment
- Standard
- RFC 7489, §3.1