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Why You Can’t Have More Than One DMARC Record

Posted on by William Zheng

Are you struggling with email deliverability issues and wondering if you can enhance your DMARC (Domain-based Message Authentication, Reporting & Conformance) setup? You’re not alone! Many businesses face challenges when trying to protect their email domains from spoofing and phishing attacks.

Understanding how to manage DMARC records effectively is crucial for safeguarding your brand and ensuring your emails land in inboxes instead of spam folders. In this article, we’ll delve into the question of using multiple DMARC records, providing you with clear steps, practical tips, and essential insights to optimize your email security strategy. Let’s unlock the potential of DMARC together!

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Can You Have More Than One DMARC Record on Your Domain?

If you’re managing email security for your domain, you’ve probably come across DMARC, which stands for Domain-based Message Authentication, Reporting & Conformance. This email authentication protocol helps prevent phishing and spoofing attacks by allowing domain owners to specify how email from their domain should be handled. A common question among domain administrators is whether they can have multiple DMARC records. The short answer is: No, you cannot have more than one DMARC record for a single domain.

Understanding DMARC Records


Multiple DMARC Records Issue - Support - more than one dmarc record

Before diving deeper, let’s clarify what a DMARC record is. It is a DNS (Domain Name System) entry that tells receiving mail servers how to handle emails that don’t pass SPF (Sender Policy Framework) or DKIM (DomainKeys Identified Mail) checks. A DMARC record can include:

  • Policy: Defines how to handle emails that fail authentication (none, quarantine, reject).
  • Reporting: Specifies where to send reports on email authentication results.
  • Subdomain Policy: Indicates whether the policy applies to subdomains.

Why Can’t You Have Multiple DMARC Records?

Having multiple DMARC records can lead to confusion and inconsistencies in how your emails are handled. Here’s why it’s crucial to maintain a single DMARC record:

  1. DNS Lookup Limitations: When a receiving mail server checks for DMARC records, it expects to find only one. If multiple records exist, the server may not know which one to follow, potentially causing your emails to be flagged or rejected.

  2. Policy Conflicts: Multiple records can have conflicting policies, leading to unpredictable behavior. This could mean legitimate emails are either accepted or rejected inconsistently.

  3. Reporting Issues: With more than one DMARC record, receiving servers may not know where to send the reports, making it difficult for you to monitor your email authentication performance effectively.

How to Properly Set Up a DMARC Record

Setting up a DMARC record is essential for securing your email. Here’s how to do it correctly:

  1. Access Your DNS Management Console: Log in to your domain registrar or hosting provider where your DNS records are managed.

  2. Create a New TXT Record:

  3. Name: Use _dmarc.yourdomain.com.
  4. Type: Select TXT.

  5. Value: Input your DMARC policy. For example:
    v=DMARC1; p=none; rua=mailto:[email protected]; ruf=mailto:[email protected]; pct=100

  6. Save the Record: Ensure that you save the changes and allow some time for DNS propagation.

Best Practices for DMARC Configuration

To maximize the effectiveness of your DMARC record, consider the following best practices:

  • Start with a Monitoring Policy: Begin with p=none to monitor your email traffic without affecting delivery. This allows you to collect reports and adjust your setup without risking legitimate emails.


Can I Have Multiple DMARC Records on My Domain? - more than one dmarc record

  • Use Aggregate and Forensic Reports: Set up reporting addresses (rua for aggregate and ruf for forensic reports) to gather data on how your emails are performing.

  • Gradually Enforce Policies: Once you have enough data, gradually move to stricter policies like p=quarantine or p=reject to enhance security.

  • Regularly Review Reports: Analyze the reports you receive to identify any issues with email authentication and adjust your SPF and DKIM records as necessary.

Challenges of DMARC Implementation

While DMARC is a powerful tool, implementing it can come with challenges:

  • Complexity of Configuration: Setting up DMARC alongside SPF and DKIM can be complex, especially for large organizations with multiple email sending sources.

  • Impact on Email Delivery: If not configured correctly, legitimate emails may be marked as spam or rejected.

  • Ongoing Maintenance: DMARC requires ongoing monitoring and adjustments based on the reports you receive.

Cost Considerations

Implementing DMARC itself is cost-free since it relies on DNS records. However, consider the following costs associated with its implementation:

  • Email Security Solutions: Some organizations opt for third-party services to manage DMARC, which can incur costs.

  • Time and Resources: Allocating time for monitoring and managing email authentication may impact your operational costs.

Conclusion

In summary, you cannot have multiple DMARC records for a single domain. A single, well-configured DMARC record is crucial for effective email authentication and security. By following best practices and regularly reviewing your configuration, you can significantly improve your email security posture.

Frequently Asked Questions (FAQs)

1. What happens if I have multiple DMARC records?**
Having multiple DMARC records can cause mail servers to become confused about which policy to apply, leading to potential email delivery issues.

2. Can I change my DMARC policy later?**
Yes, you can update your DMARC record at any time to change your policy or reporting addresses. Just ensure to save and propagate the changes.

3. What is the difference between aggregate and forensic reports?**
Aggregate reports provide a summary of authentication results over time, while forensic reports give detailed information about individual failures.

4. How long does it take for DMARC changes to take effect?**
Changes to your DMARC record may take anywhere from a few minutes to 48 hours to propagate, depending on your DNS provider.

5. Is DMARC required for all domains?**
While DMARC is not a legal requirement, it is highly recommended for all domains to protect against email spoofing and phishing attacks.

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