DMARC record

DMARC is a system that adds some rules for DKIM and SPF, so remote servers have a better idea of what your intention is for messages that fail those 2 systems.

DMARC requires both the SPF and DKIM to be present in order to work.

SPF - Sender Policy Framework

Anything that contains the word "framework" is typically crap. Here's more crap we're stuck with.

SPF allows administrators to specify which hosts are allowed to send email from a given domain by creating a specific DNS SPF record in the public DNS.

Mail Exchanger (MX records) then uses the DNS to check that mail from a given domain is being sent by a host sanctioned by that domain's administrators.

references

• http://techarena51.com/index.php/what-is-dmarc-and-how-you-can-add-it/

To add a DMARC record, go to your domain's DNS Management,

• https://help.directadmin.com/item.php?id=596