Domain-based Message Authentication, Reporting & Conformance (DMARC) is a technical specification created by a group of organizations that want to help reduce the potential for email-based abuse by solving a couple of long-standing operational, deployment, and reporting issues related to email authentication protocols.
DMARC standardizes how email receivers perform email authentication using the well-known SPF and DKIM mechanisms. This means that senders will experience consistent authentication results for their messages at AOL, Gmail, Hotmail, Yahoo! and any other email receiver implementing DMARC.
Domain-based Message Authentication, Reporting, and Conformance (DMARC)