What is DMARC?
Domain-based Message Authentication, Reporting and Conformance (DMARC) is an email authentication protocol that helps protect organisations from email spoofing. It builds upon existing protocols like SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail) by providing a mechanism for domain owners to define how receiving mail servers should handle emails that fail authentication checks.
Use Cases of DMARC_
- Prevent email spoofing: DMARC helps prevent attackers from using a company’s domain name to send fraudulent emails (phishing attempts, spam).
- Improve email deliverability: By implementing DMARC, organisations can ensure legitimate emails from their domain are properly delivered and not mistaken for spam.
- Gain visibility into email traffic: DMARC reports provide valuable insights into email activity associated with a domain, helping identify suspicious or unauthorised sending attempts.
Key Components_
- DMARC record: A TXT record published in the Domain Name System (DNS) that specifies the DMARC policy for the domain.
- SPF and DKIM: Existing email authentication protocols that DMARC leverages. SPF verifies the authorised senders for a domain, while DKIM adds digital signatures to emails for verification.
- DMARC reports: Reports sent by receiving mail servers to the domain owner, detailing information about emails that passed or failed DMARC authentication.
Microsoft cloud services like Microsoft 365 fully support DMARC. By implementing DMARC with Microsoft 365, organisations can:
- Configure DMARC policies: Define how Microsoft 365 should handle emails failing DMARC checks (e.g., quarantine, reject).
- Receive DMARC reports: Gain insights into email activity and identify potential spoofing attempts directly within Microsoft 365 security tools.
- Enhance overall email security: DMARC, combined with Microsoft 365’s security features, strengthens email protection against phishing and other email-borne threats.
By leveraging DMARC with Microsoft 365, organisations can significantly improve their email security posture and protect against email spoofing attempts.
