DMARC (Domain-based Message Authentication, Reporting & Conformance) is a protocol used to protect email domains from unauthorized use and email abuse, including spam, phishing, and other forms of email-based attacks.
DMARC is an email authentication protocol that works in conjunction with SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail) to provide email domain owners with greater control over email sent on behalf of their domain.
In this article, we will explore what DMARC records are, how to create and implement them, best practices to follow, and common issues to avoid.
What is a DMARC record?
DMARC is a protocol that enables domain owners to define policies and publish them in their DNS records, indicating how receivers should handle email messages that fail DMARC checks.
DMARC policy enforcement provides email domain owners with the ability to detect and prevent fraudulent email messages from being sent to their customers or other third parties.
DMARC is critical to maintaining email security and preventing email fraud and phishing attacks.
What are DMARC record components?
DMARC records consist of several components that work together to provide authentication and reporting mechanisms. The main components of DMARC records are:
DMARC policy: A DMARC policy is a set of instructions that tell email receivers what to do when an email message fails DMARC checks. The policy includes a reporting address where email receivers can send reports about DMARC failures.
DKIM alignment: DKIM is an email authentication method that verifies the authenticity of an email message by checking its digital signature. DMARC requires that the DKIM signature domain matches the sender domain in order to pass DKIM alignment.
SPF alignment: SPF is an email authentication method that verifies the sender’s IP address. DMARC requires that the sender IP address matches the authorized SPF record in order to pass SPF alignment.
Reporting mechanisms: DMARC includes reporting mechanisms that enable domain owners to receive feedback about DMARC failures, such as SPF and DKIM failures. These reports can be used to identify and prevent fraudulent email messages from being sent from your domain.
How to create an DMARC record?
Creating a DMARC record involves several steps, including:
Step 1: Determine your DMARC policy
The first step in creating a DMARC record is to determine your policy. DMARC policies can be set to three different levels of strictness: none, quarantine, and reject.
- None: The none policy is used to collect DMARC data, but it doesn’t instruct email receivers to take any action on messages that fail DMARC checks.
- Quarantine: The quarantine policy instructs email receivers to send email messages that fail DMARC checks to the recipient's spam or junk folder.
- Reject: The reject policy instructs email receivers to reject email messages that fail DMARC checks.
Step 2: Determine your reporting address
The next step in creating a DMARC record is to determine your reporting address. This is the email address where DMARC reports will be sent to you.
Step 3: Create your DMARC record
The next step is to create your DMARC record. The DMARC record is a TXT record that is added to your domain’s DNS zone file. The record contains the DMARC policy, the reporting address, and information about DKIM and SPF alignment.
How to implement a DMARC record?
Implementing a DMARC record involves several steps, including:
Step 1: Publish your DMARC record
After creating your DMARC record, the next step is to publish it in your domain’s DNS zone file.
Step 2: Monitor DMARC reports
The next step is to monitor DMARC reports. DMARC reports provide domain owners with valuable information about email messages that fail DMARC checks. By monitoring DMARC reports, domain owners can quickly detect and respond to email fraud and phishing attacks.
Step 3: Analyze DMARC reports and adjust your policy
The final step is to analyze DMARC reports and adjust your policy accordingly. DMARC reports provide valuable insights into email traffic patterns, including which email messages are passing DMARC checks and which ones are failing.
By analyzing DMARC reports, domain owners can adjust their DMARC policy to better protect their email domain from abuse.
Best Practices for DMARC Record
To ensure the effectiveness of your DMARC policy, it is important to follow best practices, such as:
Start with a “none” policy: Before implementing a DMARC policy, start with a “none” policy to collect data about your email traffic patterns and to identify any potential issues.
Monitor DMARC reports regularly: Regularly monitor DMARC reports to identify email fraud and phishing attacks.
Implement DKIM and SPF: Implement DKIM and SPF authentication mechanisms to ensure alignment with DMARC policy.
Test your DMARC policy: Test your DMARC policy by sending test messages to various email receivers to ensure that your policy is functioning correctly.
Educate your employees: Educate your employees about email security best practices, including how to identify phishing and fraudulent emails.
Common DMARC Record Issues
When implementing a DMARC policy, it is important to avoid common issues, such as:
Incorrectly configured DKIM and SPF records: If your DKIM or SPF records are incorrectly configured, your DMARC policy will not work correctly.
Overly strict DMARC policies: Overly strict DMARC policies can cause legitimate email messages to be rejected, resulting in customer complaints and lost business.
Lack of monitoring: Failure to monitor DMARC reports can result in missed opportunities to prevent email fraud and phishing attacks.
Conclusion
DMARC is a critical email authentication protocol that helps prevent email fraud and phishing attacks. By creating and implementing a DMARC policy, domain owners can protect their email domain and their customers from email-based attacks.
To ensure the effectiveness of your DMARC policy, it is important to follow best practices, test your policy regularly, and monitor DMARC reports.
By doing so, you can help ensure the security of your email domain and protect your customers from email-based threats.