About Domain-based Message Authentication (DMARC)
Domain-based Message Authentication, Reporting and Conformance (DMARC) is a sender-published policy for email messages that targets messages that fail authentication. This works to prevent spoofing, where someone else impersonates your organization to send viruses, malware, or scam recipients. By default, most ESPs will set up your account with SPF and DKIM, but might require additional configuration to implement DMARC.