How does relaxed domain alignment work in DMARC and SPF?
Summary
What email marketers say8Marketer opinions
Email marketer from SendLayer explains that when using relaxed alignment, the domain only needs to have the same organizational domain, not the exact same one. For example, yourdomain.com and mail.yourdomain.com would align.
Email marketer from Email Geeks explains that SPF doesn't have the concept of alignment or inheritance like DMARC. If there’s no SPF record published at subdomain3.domain.com, then it won’t check domain.com or even look at subdomain1.domain.com.
Email marketer from Mailjet explains that relaxed DMARC alignment is the default mode. With relaxed alignment, a match occurs if the organizational domains match. For example, mail.example.com and example.com would align.
Email marketer from Postmark explains that relaxed DMARC alignment means the organizational domain of the From address must match the organizational domain of the SPF or DKIM authenticated domain. For example, 'example.com' and 'subdomain.example.com' would align.
Email marketer from URIports shares that relaxed alignment offers flexibility by allowing subdomains of the same organizational domain to align. This is in contrast to strict alignment, which requires an exact domain match.
Email marketer from SparkPost shares that relaxed alignment in DMARC permits a match at the organizational domain level. This means subdomains can differ as long as they fall under the same organizational domain.
Email marketer from Reddit shares that in DMARC, if you are using relaxed alignment, then subdomains are accepted, the root domain must match in order for it to work.
Email marketer from EasyDMARC explains that organizational domains are key to relaxed alignment. If the From domain is sub.example.com, then a return-path of another.example.com would be considered aligned.
What the experts say4Expert opinions
Expert from Email Geeks explains that any two hostnames that share an organizational domain are aligned under DMARC.
Expert from Email Geeks clarifies that there’s SPF alignment for DMARC.
Expert from Email Geeks confirms that any domain 'under' domain.com is aligned with anything else 'under' it for relaxed DMARC alignment.
Expert from Word to the Wise, Laura Atkins, explains that relaxed DMARC alignment lets you match an SPF or DKIM authenticated domain and a From: domain at the organizational level domain. For example, sub.example.com can align with example.com.
What the documentation says4Technical articles
Documentation from RFC 7489 defines relaxed alignment as allowing the organizational domain to match. The 'From' domain and the authentication domain (SPF's MAIL FROM or DKIM's d=tag) do not need to be an exact match; they only need to share the same organizational domain.
Documentation from Microsoft responds that SPF checks the domain used during the SMTP handshake (MAIL FROM). Relaxed alignment in the context of SPF for DMARC means the MAIL FROM domain only needs to share the same organizational domain as the From header.
Documentation from DMARC.org explains that relaxed alignment allows a match if the organizational domains are the same, regardless of subdomains. For SPF, the domain in the Return-Path/Mail-From must pass SPF validation. For DKIM, the d= domain in the DKIM signature must align with the domain in the From: header.
Documentation from AuthSMTP responds that relaxed DMARC alignment permits matches if the organizational domains are the same, enabling greater flexibility than strict alignment. For example, 'example.com' and 'anything.example.com' would align.