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AuthenticationA free tool by NullFortis
DMARC Checker
Inspect your DMARC policy
What is it?
DMARC (Domain-based Message Authentication, Reporting & Conformance) is the policy layer built on top of SPF and DKIM — it tells receiving servers what to do (nothing, quarantine, or reject) with mail that fails authentication, and where to send reports about it.
Why it matters
SPF and DKIM alone don't stop spoofing unless something actually enforces consequences for failing them — DMARC is that enforcement, plus visibility into who's sending mail as your domain.
Impact if ignored
No DMARC record means no enforcement and no visibility, legitimate senders or not. A policy of reject without properly aligned SPF/DKIM first can also silently block your own real mail.
Common use cases
- Track your domain's progress from monitoring (p=none) toward full enforcement (p=reject)
- Confirm your aggregate-report address is correctly configured
- Audit your policy before a security review