DMARC (Domain-based Message Authentication, Reporting and Conformance) is a method that helps prevent spoofing. Spoofing is the abuse of your domain in such a way that emails appear to originate from it. DMARC validates whether an email is legitimate.

For more information, refer to these articles:

• Use DMARC to validate email from Microsoft
• DMARC: What is it and why do you need it?

Procedure

1. Open the MX Toolbox tool.
2. Paste the full email, including the headers and the body.
3. Click Analyze Header.
4. Review the results.