This text discusses the implementation of DMARC (Domain-based Message Authentication, Reporting & Conformance) using SendGrid for email deliverability protection against spoofing attempts. It provides a step-by-step guide on how to add SPF and DKIM records, authenticate domains, verify senders, and configure DMARC policies from p=none to p=quarantine or p=reject. The text also emphasizes the importance of monitoring email reports for potential issues and mentions a free DMARC monitoring tool offered by SendGrid in partnership with Valimail.