DMARC policy stages: none, quarantine and reject

p=none requests reports but does not ask receivers to quarantine or reject failing mail. It is useful during sender discovery, not a completed protection state.

p=quarantine asks receivers to treat failures as suspicious. Final handling remains the receiver's decision.

A pct value can apply enforcement to a portion of mail while data is reviewed. Partial coverage must not be mistaken for full enforcement.

p=reject asks receivers not to accept mail that fails DMARC. Reach this stage only after every legitimate sender has a reliable aligned authentication path.

pct controls the percentage subject to the requested policy. sp can set a separate policy for subdomains; without it, subdomains inherit the organizational-domain policy.