How DMARC works
DMARC builds on two other standards:
- SPF: lists the servers allowed to send email for your domain.
- DKIM: adds a digital signature that proves an email wasn’t changed on the way.
An email passes DMARC when SPF or DKIM passes and matches the domain in the From address. Your DMARC policy, published as a TXT record in your DNS, says what should happen to emails that fail:
p=none: deliver as usual, but report (a good starting point).p=quarantine: send to the spam folder.p=reject: block the email.
Why DMARC matters
It stops criminals from sending phishing emails in your name, and it improves the delivery of your own emails. Since 2024, Gmail and Yahoo require a DMARC record from bulk senders, and a DMARC policy of quarantine or reject is needed before your logo can appear in inboxes through BIMI.
Example record: v=DMARC1; p=quarantine; rua=mailto:[email protected]