What is DMARC?
A policy that tells receivers what to do with mail that fails SPF and DKIM alignment, and where to send reports.
How it works in practice
DMARC passes when SPF or DKIM passes and aligns with the domain in the visible From address. The domain owner publishes a policy at _dmarc.domain: none (monitor), quarantine (spam folder) or reject (refuse). Gmail, Yahoo and Outlook.com require a DMARC record from bulk senders, and p=none satisfies that requirement.
The common mistake
Moving straight to p=reject without reading the aggregate reports, which blocks legitimate mail from a tool nobody remembered.
Check it yourself
Related terms
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