Domain-based Message Authentication, Reporting, and Conformance (DMARC) builds on SPF and DKIM to provide instructions on how to handle emails that fail authentication checks. To set up DMARC:
Create a DMARC policy record in your DNS settings as a TXT record. The record should include parameters like v=DMARC1; p=none; rua=mailto:example@example.com. Save the record and monitor the reports sent to your specified address.