Domain-based Message Authentication, Reporting, and Conformance (DMARC)

DMARC is an email-authentication policy that uses SPF and DKIM results plus domain alignment to guide message handling.

Format
Email & Communication
Updated
Updated
Glossary Email & Communication
Domain-based Message Authentication, Reporting, and Conformance Also known as DMARC.Aliases: DMARC policy.

Definition

DMARC is an email-authentication policy that uses SPF and DKIM results plus domain alignment to guide message handling.

How it works

With DMARC, you publish a policy in DNS telling receivers what to do with mail that claims to be from your domain but fails aligned SPF or DKIM checks: monitor it, quarantine it, or reject it. You can also request reports showing who is sending as your domain — well worth reading before you tighten the policy. Receivers keep the final say on delivery, but most honor a clear policy.

Example: Most domains start with a monitor-only policy, study the reports, then move toward quarantine or reject.

Often confused: DMARC does not authenticate anything itself — it decides what happens based on SPF and DKIM results.

Sources

Last reviewed 2026-07-19.