DMARC alignment
Also called: identifier alignment, relaxed alignment, strict alignment
The requirement that the domain in the visible From address match the domain validated by SPF or DKIM. In relaxed mode a shared organisational domain is enough, so subdomains align; in strict mode the fully qualified domain names must match exactly.
In plain terms
Passing SPF or DKIM is not enough — the domain that passed has to be the one your reader can see.
Why it matters for deliverability
Alignment is the single most misunderstood part of DMARC. A message can pass SPF cleanly and still fail DMARC, because the envelope domain belonged to the sending platform rather than to you.
What to do about it
- Check alignment against the visible From domain, not just the pass/fail of each mechanism.
- Configure a custom Return-Path or DKIM signing domain at any provider sending on your behalf.
- Keep relaxed alignment unless you have a specific reason for strict — subdomain sending is common.
Source
“When the domain in the RFC5322.From address matches a domain validated by SPF or DKIM (or both), it has Identifier Alignment.”
Checked 2026-08-29
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Definitions reviewed 2026-08-29. Spotted something wrong? Tell us.
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