DMARC

v=DMARC1; p=none; fo=1; rua=mailto:me@example.com

Here’s what this rule does:

  • This DMARC example tells the server to send a report by email if SPF or DKIM fail the server’s checks.
  • We’re using p=none because it’s the least restrictive setting. You’ll still get email reports if there’s an issue with your DNS, but it’s unlikely to affect your own emails from being delivered. If you start to get suspicious DMARC reports, you could change this part of the rule to p=quarantine.
  • Be sure to change the mailto: address. It should ideally be set to the email address that your mailer service provides in its documentation. If it doesn’t provide one, you can use an email address at your own domain.

Here’s what our DMARC record looks like. We recommend leaving the TTL setting on Auto. If you have to choose a value, it’s best to keep the TTL short – in other words, hours rather than days.