p=quarantine — send failing mail to spam

p=quarantine asks receiving mail servers to deliver DMARC-failing mail to the recipient's spam folder rather than the inbox, instead of rejecting it outright. It is the usual middle step between p=none and p=reject, giving you a chance to catch legitimate senders you missed before enforcement gets stricter.

pct= can apply this to only a percentage of failing mail during rollout — see the pct article.