Without DMARC, hackers and other malicious users can impersonate messages, making them appear to come from your organization or domain. Turning off DMARC puts your users and your contacts at risk for spam, spoofing, and phishing.

DMARC ensures the destination email systems trust messages sent from your domain. Using DMARC with SPF and DKIM gives organizations more protection against spoofing and phishing email. DMARC helps receiving mail systems decide what to do with messages from your domain that fail SPF or DKIM checks.