Glossary
DKIM Alignment (DMARC)
DKIM alignment verifies the d= domain in the DKIM-Signature matches the From: header’s organizational domain. Relaxed alignment allows subdomain relationships; strict requires exact match. Most ESPs achieve alignment via CNAME or TXT DKIM on your domain.
When DKIM saves DMARC
If Return-Path is on the ESP’s domain, aligned DKIM to your brand domain still satisfies DMARC when SPF alignment fails.
FAQ
What if I have multiple DKIM signatures?
DMARC can pass if any signature aligns — policy-dependent.
Does mailing list break DKIM?
Often yes — body changes break the signature unless the list re-signs.
What is adkim=?
DMARC tag for strict vs relaxed DKIM alignment.