A domain administrator can use DMARC to determine how email messages using an address from the sender’s domain will be perceived by a receiving system. DMARC informs the receiver which validations (SPF, or DKIM, or both) will pass. This validation ensures that the email message was sent by the sender identified by the From: address.
Consider setting up a DMARC policy record with your domain provider. A DMARC policy record is a DNS resource record of the type TXT. The shortest valid DMARC policy record is v=DMARC1; p=none. To assist with email deliverability analysis, include an email address (or addresses) to which reports of aggregated feedback can be sent. Use the rua tag to list the address (or addresses) for aggregate feedback reports in your policy. For example, rua=mailto:aggrep@example.com.
Important
Setting up a DMARC policy affects the entire email infrastructure of your company. The administrator or local IT Department is responsible for your company’s email infrastructure should be involved in setting up a DMARC policy record with your domain provider. Consider carefully how strong a policy to implement as it may have consequences. For example, if you use the optional rua tag, it might consume some of your company’s email resources, depending on the volume of received reports.
For more information about DMARC, go to https://dmarc.org/overview. You might find the Anatomy of a DMARC resource record and How Senders Deploy DMARC in 5-Easy Steps sections of that page particularly helpful. See also the DMARC specification, RFC 7489.