What is Domain Based Message Authentication Reporting and Conformance?
What is Domain-Based Message Authentication, Reporting & Conformance (DMARC)? A Comprehensive Guide
It is an email authentication protocol designed to detect and prevent email spoofing, a technique commonly used in phishing attacks. DMARC helps ensure that only authorised senders can send emails from a specific domain, allowing email recipients to verify the legitimacy of incoming emails.
The main goal of DMARC is to improve email security by making it harder for malicious actors to impersonate a legitimate organisation and send fraudulent emails to recipients. DMARC achieves this by combining two existing authentication methods, SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail), with a reporting mechanism.
How Does DMARC Work?
DMARC functions by using a combination of email authentication techniques: SPF and DKIM.
- SPF (Sender Policy Framework)
SPF allows the domain owner to specify which IP addresses are authorised to send emails on behalf of their domain. When a receiving email server gets an incoming email, it checks the SPF record to verify if the sending server’s IP is allowed to send emails from that domain. - DKIM (DomainKeys Identified Mail)
DKIM uses cryptographic signatures to authenticate the sender’s identity. The email’s header is signed with a private key, and the receiving server uses a public key published in the DNS records of the sender’s domain to verify that the email was indeed sent by the domain it claims to represent and hasn’t been altered in transit. - DMARC Policy
DMARC builds on SPF and DKIM by adding a policy layer. Domain owners create a DMARC record in their DNS settings, specifying how receiving email servers should handle emails that fail SPF and/or DKIM checks. DMARC allows the domain owner to define one of three actions:- None: No action is taken if the email fails authentication (used for monitoring purposes).
- Quarantine: Emails that fail authentication are marked as spam or moved to the junk folder.
- Reject: Emails that fail authentication are rejected outright, and not delivered to the recipient.
- DMARC Reporting
One of the key features of DMARC is the reporting mechanism. DMARC provides domain owners with feedback about their email authentication status. These reports help identify legitimate and unauthorised senders, making it easier for organizations to monitor email activity and adjust their policies accordingly.
Benefits of DMARC
- Improved Email Security
The primary benefit of DMARC is enhanced security. By implementing DMARC, organisations can significantly reduce the risk of email spoofing and phishing attacks. DMARC makes it more difficult for cybercriminals to send fraudulent emails from a domain they don’t own. - Brand Protection
DMARC helps protect an organisation’s brand by preventing attackers from impersonating the company through email. This protects customer trust, as recipients will be less likely to fall for phishing emails or fraud attempts. - Enhanced Email Deliverability
DMARC improves email deliverability by ensuring that only legitimate emails from authorised senders are delivered to inboxes. This reduces the likelihood of emails being flagged as spam, making sure that genuine communications reach the intended recipients. - Actionable Reporting
DMARC’s reporting feature provides detailed insights into the emails being sent from your domain, including failed authentication attempts. This gives domain owners the opportunity to take corrective action and fine-tune their email security practices. - Compliance with Security Standards
As email security becomes a higher priority for businesses, DMARC can help organisations meet industry regulations and cybersecurity best practices. For example, DMARC is part of the email security frameworks required by certain industries, such as financial services and healthcare, to comply with data protection standards.
Implementing DMARC
Implementing DMARC may seem complex, but the process is relatively straightforward when following these steps:
- Set Up SPF and DKIM
Before configuring DMARC, ensure that SPF and DKIM records are set up for your domain. These two protocols work alongside DMARC to verify the authenticity of emails. - Create a DMARC Record
Create a DMARC record in your domain’s DNS settings. This record will define your DMARC policy and specify the actions to take when emails fail authentication. - Monitor Reports
Once DMARC is implemented, monitor the reports sent by email receivers. This helps you understand how your email is being authenticated and identifies any sources of fraudulent activity. - Adjust Policies as Needed
Initially, you may want to set the DMARC policy to “none” to collect data and monitor authentication results. Once you have analysed the reports and ensured that legitimate emails are being delivered correctly, you can implement stricter policies, such as “quarantine” or “reject.”
DMARC Best Practices
- Start with Monitoring
Start by setting your DMARC policy to “none” so you can monitor email traffic and identify any issues before implementing stricter policies. - Regularly Review Reports
Analyse DMARC reports regularly to ensure there are no unauthorised senders using your domain. Review SPF and DKIM alignment and make adjustments as necessary. - Gradually Increase Policy Strictness
Once you are confident that legitimate emails are being authenticated correctly, gradually increase your DMARC policy to “quarantine” and then “reject” to fully protect your domain. - Educate Your Team
Ensure that your team is aware of DMARC policies and understands the importance of email security to prevent misuse of your domain.
Conclusion
Domain-Based Message Authentication, Reporting & Conformance (DMARC) is a powerful tool for improving email security and preventing email fraud. By implementing DMARC, organisations can protect their brand, reduce phishing risks, and ensure the integrity of email communications. As email-based attacks become more sophisticated, adopting DMARC and other security protocols is essential for organisations that want to stay ahead of cyber threats and safeguard their digital assets.
Talk to us about our Shield package for your cybersecurity needs. For more information about how we can help you with your business IT needs, call us on 0333 444 3455 or email us at sales@cnltd.co.uk.
