What is a DMARC record?
DMARC, which stands for Domain-based Message Authentication, Reporting, and Conformance, is a policy framework that works alongside SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail) to provide enhanced email authentication and protection against email spoofing and phishing attacks. DMARC helps domain owners specify how email servers should handle messages that fail SPF or DKIM checks.
How does DMARC work?
- Alignment: DMARC requires both SPF and DKIM to be in place. It checks for alignment between the “From” domain in the email’s header, the domain used in the SPF record, and the domain used in the DKIM signature. All three domains must match or align properly for DMARC to consider the email authenticated.
- DMARC Policy: The domain owner publishes a DMARC policy in their DNS settings. This policy indicates how receiving email servers should treat emails that don’t pass SPF or DKIM authentication. The policy can instruct the recipient server to either quarantine the message, mark it as spam, or reject it entirely.
- Reporting: DMARC also provides a reporting mechanism that allows domain owners to receive feedback from email receivers about the authentication results of their emails. These reports provide information about which emails passed or failed DMARC checks and how they were handled by recipient servers.
What are the benefits of DMARC?
By implementing a DMARC policy, domain owners can achieve several benefits:
- Improved Authentication: DMARC ensures that only legitimate emails from authorized senders are delivered, reducing the risk of phishing and spoofing attacks.
- Visibility: The reporting feature of DMARC provides insights into how email traffic is being handled across different receiving servers, helping domain owners identify unauthorized senders and authentication issues.
- Enhanced Reputation: Properly configured DMARC policies can contribute to a domain’s reputation, as it demonstrates a commitment to email security.
It’s important to note that implementing DMARC can be complex, especially for larger organizations. It requires careful configuration of SPF and DKIM records, as well as understanding the potential impact of policy settings on email deliverability. It’s recommended to gradually roll out DMARC policies, starting with a monitoring-only mode to gather data and ensure that legitimate email sources are properly aligned before moving to a stricter enforcement policy.
