How to fix dmarc policy none on Ghost

Steps for Ghost

1. Ghost (Ghost Pro or self-hosted) sends newsletter and transactional mail through Mailgun by default. In Ghost Admin → Settings → Email, complete the Mailgun custom domain setup (Ghost walks you through adding the required DNS records).
2. Those DNS records include DKIM — once published, Mailgun-sent mail will be DKIM-signed and aligned.
3. At your DNS provider, update the _dmarc TXT record from p=none to p=quarantine, monitor reports, then advance to p=reject.

What is dmarc policy none?

DMARC (Domain-based Message Authentication, Reporting & Conformance) is a DNS record that tells the world's email providers what to do when they receive an email claiming to be from your domain. The policy tag (`p=`) controls the action: `none` means "do nothing — just watch," `quarantine` means "send suspicious mail to the spam folder," and `reject` means "refuse to deliver it at all." Right now your record is set to `p=none`, which is a read-only monitoring mode — it collects reports but never protects anyone. Moving to `p=quarantine` and eventually `p=reject` turns DMARC into an actual shield against email fraud.

With `p=none`, anyone in the world can send email that appears to come from your domain — your customers' inboxes, your suppliers, even your staff — and mail servers will deliver it without question. This is the primary technique used in phishing and business email compromise (BEC) attacks, where criminals impersonate your brand to steal money or credentials from your customers. Beyond security, Google and Yahoo now require a DMARC policy (at minimum `p=none` with reporting, but ideally stricter) for bulk senders, and staying in monitor-only mode signals poor email hygiene that can hurt your domain's sender reputation and deliverability. Moving to `p=reject` demonstrably reduces phishing abuse of your brand, protects customer trust, and is increasingly expected by enterprise buyers and payment processors performing vendor security assessments.

See the complete Dmarc policy none guide for every platform and the full background.