DMARC (Domain-based Message Authentication, Reporting & Conformance) is an email authentication protocol designed to protect your domain from being used in email spoofing, phishing attacks, and other forms of email fraud. It builds upon two existing technologies: SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail).

Think of DMARC as a policy enforcement layer. It tells receiving email servers (like Gmail, Outlook, Yahoo) what to do with emails that fail SPF and DKIM checks for your domain. You can set your DMARC policy to:

• none: Monitor only. Deliver emails even if they fail. This is for initial setup.
• quarantine: Send failing emails to the recipient's spam or junk folder.
• reject: Block failing emails entirely. This is the most secure setting.

A critical feature of DMARC is reporting. When you publish a DMARC record, receiving servers send you detailed reports (via email) showing who is sending email using your domain and whether those emails are passing authentication. This visibility is invaluable for identifying legitimate services and spotting malicious activity.

Implementing DMARC is a crucial step for improving email deliverability, protecting your brand's reputation, and ensuring your customers' safety. Without it, cybercriminals can easily impersonate your domain, damaging trust and potentially leading to data breaches.