The DMARC policy is the p= tag in a DMARC record. It tells receivers what to do with email that claims to be from your domain but fails DMARC.
The three policies
p=none: deliver as usual, just send reports. The starting point.p=quarantine: treat failing email as suspicious, usually sending it to spam.p=reject: refuse failing email outright.
Which one for cold email
Since 2024, Gmail and Yahoo require a DMARC record from anyone sending in volume; p=none meets that rule. For a cold email sending domain, start with p=none and a report address, check the reports for a few weeks to make sure every service sending as your domain passes, then move to quarantine. A stricter policy protects your domain from spoofing; it doesn't by itself improve inbox placement.
Related tags
sp= sets a separate policy for subdomains, and pct= applies the policy to only part of the failing mail while you move up. Build a record with the free DMARC generator.