Even now in 2024 email is still the primary mode of communication for personal and business, protecting against email fraud and ensuring the authenticity of messages is important. One very effective tool for achieving this is DMARC, or Domain-based Message Authentication, Reporting & Conformance. DMARC enhances the security of your email domain by working with existing authentication technologies like SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail). In this blog post, we’ll explore what DMARC is, how it works, and why it’s an important component of your email security.
What is DMARC?
DMARC is an email authentication protocol that builds on SPF and DKIM by providing a mechanism for domain owners to specify how email messages that fail authentication checks should be handled. It also allows domain owners to receive reports on email authentication activity, helping them monitor and improve their email security.
How Does DMARC Work?
1. First the domain owner publishes a DMARC policy in DNS (Domain Name System) as a TXT record. This record defines the policy for handling emails that fail SPF and/or DKIM, such as whether to quarantine or reject them completely. This record also provides an email address to send reports to.
2. When an email is received, the recipient’s mail server performs both SPF and DKIM checks to verify the authenticity of the email. DMARC then uses these results to determine how to proceed with the email based on the policy specified in the DMARC record.
3. DMARC generates aggregate and failure reports that are sent to the email address specified in the DNS entry. Aggregate reports provide a summary of authentication activity, while forensic reports provide more detailed information about individual failed authentication attempts.
Why is DMARC Important?
1. DMARC builds on SPF and DKIM to provide a more robust framework for preventing email spoofing and phishing. It ensures that unauthorized senders cannot impersonate your domain.
2. By implementing a DMARC policy, you can improve the likelihood that your legitimate emails will reach your customer’s inboxes instead of being sent to spam.
3. DMARC reports give you a valuable insight into how your domain is being used and whether there are unauthorized attempts to send emails from your domain. This visibility helps you to take proactive measures to secure your email as well as find places you may have misconfigurations.
How to Implement DMARC
1. First you need to decide on your DMARC policy, which includes how you want to handle emails that fail authentication checks (i.e., quarantine, reject) and where you want to receive reports.
2. Next use a service like MonitorDMARC to generate your DMARC record and publish the DMARC policy in your domain’s DNS as a TXT record. The record will include your policy settings and the email addresses for reporting.
3. Use the reports generated by DMARC to monitor your email traffic and adjust your policy as needed. This may involve refining SPF and DKIM settings or updating the DMARC policy based on the insights you gain. Services like MonitorDMARC can help you simplify this process.
4. Start with a “none” policy to gather data and then gradually move to stricter policies like “quarantine” or “reject” as you fine-tune your authentication settings and know you SPF and DKIM are set properly.
Conclusion
DMARC is a great tool that improves email security by giving you a way to enforce authentication policies and get visibility into email activity. By implementing DMARC, you can protect your domain from email spoofing, improve email deliverability, and gain great insights into how your domain is being used. For the best results, integrate DMARC with SPF and DKIM with a third party like MonitorDMARC to create a complete email security strategy.