Understanding DMARC Policy

What is a DMARC policy? A DMARC policy allows a sender’s domain to indicate that their email messages are protected by SPF and/or DKIM and tells a receiver what to do if neither of those authentication methods passes – such as to reject the message or quarantine it. The policy can also specify how an email receiver can report back to the sender’s domain about messages that pass and/or fail. These policies are published in the public Domain Name System (DNS) as text TXT records. DMARC does not directly address whether or not an email is spam or otherwise fraudulent. Instead, DMARC can require that a message not only pass DKIM or SPF validation but that it also pass alignment. Under DMARC a message can fail even if it passes SPF or DKIM but fails alignment. Setting up DMARC will improve the deliverability of messages from legitimate senders.