DMARC (Domain-based Message Authentication, Reporting, and Conformance) is an email authentication protocol that helps prevent email fraud and phishing attacks. It allows email senders to specify which email servers are authorized to send emails on their behalf, and provides a mechanism for email receivers to verify the authenticity of incoming emails. DMARC also includes reporting capabilities, allowing senders to receive feedback on the delivery and disposition of their emails. By implementing DMARC, organizations can protect their brand reputation and ensure the security of their email communications.