Fighting Email Spoofing: A Step-by-Step Guide to Setting Up DMARC for Your Domain

In this blog post, let's dive into the world of email spoofing frauds and learn how to protect your domain. I learned about the topic from podcast.

Email spoofing is a common problem in the digital world, where attackers can send fraudulent emails that appear to be from a legitimate source. DMARC, or Domain-based Message Authentication, Reporting and Conformance, is a protocol designed to combat email spoofing by verifying the authenticity of emails. In this blog post, we'll go over how to set up DMARC and provide some examples of DMARC configuration.

  1. Start by creating a DMARC record DMARC uses a DNS TXT record to specify email authentication policies for your domain. The record will include the following elements:
  • v=DMARC1: This indicates the version of DMARC being used.
  • p=none: This specifies the policy to apply to emails that fail authentication checks. In this case, emails that fail will not be rejected, but a report will be generated.
  • pct=100: This determines the percentage of messages that will be checked. 100% means all messages will be checked.
  • rua: This specifies the email address where aggregate reports should be sent. In this example, reports will be sent to [email protected].
  • sp=none: This specifies the policy for subdomains. In this example, no policy is applied to subdomains.
  • aspf=r: This specifies the alignment mode for SPF checks. In this example, it is set to relaxed.

Here's an example of a basic DMARC record:

v=DMARC1; p=none; pct=100; rua=mailto:[email protected]; sp=none; aspf=r;
  1. Add Forensic Reporting Forensic Reporting is an optional feature of DMARC that provides detailed information about emails that fail authentication checks. It is recommended to enable this feature to help identify the source of the problem and fix it. To add Forensic Reporting to your DMARC record, modify the record as follows:
  • ruf: This specifies the email address where forensic reports should be sent. In this example, reports will be sent to [email protected].
  • fo=1: This specifies the format of the forensic reports. In this case, it is set to "full."

Here's an example of a DMARC record with Forensic Reporting enabled:

v=DMARC1; p=none; pct=100; rua=mailto:[email protected]; ruf=mailto:[email protected]; sp=none; aspf=r; fo=1;
  1. Monitor and Test Your DMARC Configuration To ensure that DMARC is working correctly, it is recommended to monitor and test your configuration. Postmark offers a free weekly email service to help monitor and implement DMARC.

You can also use to test your DMARC configuration. The DMARC analyzer will send a test email to your email address and provide you with a report on the DMARC compliance status of your domain.

In conclusion, DMARC is a protocol that helps prevent email spoofing and increases the security of email communication. By following the steps outlined in this blog post, you can set up DMARC with recommended settings and tools for testing. Remember to tighten your DMARC policy as you become more confident in your configuration.