Domain-based Message Authentication, Reporting & Conformance (DMARC), is an email authentication, policy, and reporting protocol. It builds on the SPF and DKIM protocols to improve and monitor protection of the domain from fraudulent email
"To select a suitable DMARC solution for your business, you need to think about a variety of factors. We've talked to several cybersecurity professionals to get their insight on the topic.
DMARC solutions add security to business email systems by ensuring DKIM and SPF standards are in place to mitigate risks from fraudulent use. They evaluate every inbound and outbound email for these security standards and can integrate with Secure Email Gateway solutions to block malicious activity..."