Glossary · Email & deliverability · Last updated October 31, 2026

DMARC

DMARC is a DNS policy that tells receivers what to do with mail that fails SPF and DKIM alignment for your domain, and where to send reports.

Also called: Domain-based Message Authentication, Reporting, and Conformance.

DMARC builds on SPF and DKIM. It checks that at least one of them passes *and* aligns with the domain in the visible From address. A domain publishes a TXT record at _dmarc.yourdomain.com, such as v=DMARC1; p=none; rua=mailto:reports@yourdomain.com, where p is the policy: none (monitor), quarantine or reject.

The original specification was RFC 7489. In 2026 the IETF published RFC 9989, a standards-track version that obsoletes it, with reporting split into companion documents. Records still start v=DMARC1.

Google requires bulk senders to Gmail to publish DMARC, and says the policy can be none. Yahoo requires a valid DMARC policy of at least p=none that passes. Outlook.com requires p=none or stricter, aligned with SPF or DKIM, for domains sending more than 5,000 emails a day.

For cold email, publish at least p=none on each sending domain and read the aggregate reports for a few weeks. They show every server sending as your domain, which catches forgotten tools before you tighten the policy.

Example

An agency publishes v=DMARC1; p=none; rua=mailto:dmarc@getacmeagency.com. Reports show its sequencer is passing DKIM but not SPF alignment, which is fine for DMARC because one aligned pass is enough.

Sources

  1. 1.IETF, RFC 9989: Domain-based Message Authentication, Reporting, and Conformance (DMARC)
  2. 2.Google, Email sender guidelines
  3. 3.Yahoo, Sender best practices
  4. 4.Microsoft, Outlook.com Postmaster policies

Related terms

Further reading

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