An email-validation system designed to detect and prevent email spoofing. DMARC helps to counter certain phishing and spam email exploits, such as using false sender addresses in email messages that appear to originate from legitimate organizations. It counters the illicit usage of the exact domain name in the From: field of email message headers. DMARC is built on top of SPF and DKIM. You must have both an SPF and a DKIM record published for the domain to set DMARC policies.