What is DMARC? (Email glossary definition)

DMARC (Domain-based Message Authentication, Reporting & Conformance) is an email-authentication policy framework defined in RFC 7489. It builds on SPF and DKIM by adding two things: a policy (what receivers should do with mail that fails authentication) and reporting (where receivers should send aggregate data about who is sending mail as you).

A DMARC record lives at _dmarc.yourdomain.com and looks like:

v=DMARC1; p=quarantine; rua=mailto:dmarc-reports@yourdomain.com; pct=100

The three policies:

• p=none: observation only, no enforcement. Start here.
• p=quarantine: send failing mail to spam folder.
• p=reject: refuse failing mail outright. End state.

Gmail and Yahoo now require DMARC for bulk senders (5,000+ messages/day). The progressive rollout (none → quarantine → reject over several weeks of observation) is the standard practice.

See what is DMARC for the full explanation and progressive DMARC setup for the rollout playbook. Free DMARC checker on our site.