What is DMARC?

What do the DMARC policies mean?

The p tag in the record sets the policy. RFC 9989, the current DMARC standard (May 2026), defines three values:

Policy	What it tells receivers
p=none	"The Domain Owner offers no expression of preference."
p=quarantine	"The Domain Owner considers such mail to be suspicious."
p=reject	Every failure is "a clear indication that the use of the domain name is not valid."

A record with no p tag is treated as p=none. Receivers still decide: the RFC says they "SHOULD NOT reject messages solely because of a published policy of 'reject'."

Where should you start?

At p=none, with reports switched on. In the RFC's words, "Domain Owners usually start with 'p=none'," so the reports can show any server or outside sender missed in the SPF and DKIM setup. Fix what they show before you move to a stricter policy.

What is alignment?

DMARC passes when SPF or DKIM passes for a domain that matches the one in the From address. The RFC allows two modes, "relaxed" and "strict": relaxed accepts a domain from the same organization, such as a subdomain, and strict needs the exact domain.

Do you need DMARC for cold email?

Google requires DMARC from senders of more than 5,000 messages a day to Gmail accounts, and says the policy "can be set to none." For B2B, set it up anyway, aligned with your From domain: gateways check it too.

Check your domain

The free deliverability check looks up a domain's MX, SPF, DKIM and DMARC records in public DNS and explains each one. Dylan's deliverability is powered by Folderly.