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What is DMARC?
Reviewed by the Free Domain Mail editorial team · Updated
DMARC helps receivers recognise authentic mail using your visible domain and gives you a staged path to reduce impersonation.
Start with visibility
DMARC aligns SPF and DKIM with the visible From address and tells receivers what to do when the checks fail.
Start in monitoring mode, review reports, then move to quarantine or reject only when every legitimate sender is covered.
Alignment matters
A message can pass SPF for a different return-path domain and still fail DMARC alignment. The same applies to DKIM.
Use a reporting mailbox you control. Reports help identify systems that send on your behalf before enforcement is increased.
Common mistakes to avoid
- Moving directly to p=reject without monitoring.
- Using an unmonitored rua address.
- Forgetting transactional tools, support platforms or web forms that send mail.
Frequently asked questions
Which policy should I start with?
Use p=none while you discover legitimate senders.
Does DMARC guarantee inbox placement?
No. It is authentication, not a guarantee of reputation or recipient engagement.
Technical references
Primary specifications and provider documentation relevant to this guide: