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Email authentication
What is DMARC?
How a domain tells receiving mail systems what to do when authentication fails.
The short version
DMARC helps a domain owner control mail that claims to use their domain. It checks whether SPF or DKIM aligns with the visible From domain, then applies the published policy.
Why businesses use it
Without an enforced DMARC policy, an unauthorized sender may have more room to impersonate the real domain. Reporting also creates a view of systems sending on the domain’s behalf.
A careful rollout starts with visibility, fixes legitimate senders and advances policy only when the domain is ready.