How to Troubleshoot DMARC Authentication Failures 1

How to Troubleshoot DMARC Authentication Failures

Understanding DMARC

Domain-based Message Authentication, Reporting, and Conformance (DMARC) is an email validation system used to protect your domain from email spoofing. DMARC works by verifying that the sender of an email message is authorized to use your domain name. It is a collaborative effort between email providers and domain owners to protect recipients from phishing scams and spam emails. DMARC looks for two different authentication protocols – Sender Policy Framework (SPF) and DomainKeys Identified Mail (DKIM) when validating email messages.

Why DMARC Authentication Fails?

DMARC authentication failures occur when an email message fails both SPF and DKIM authentication policies set by the domain owner. Some reasons why DMARC authentication might fail include:

  • Sending disallowed IP addresses that do not match SPF records.
  • Signing emails with expired or invalid DKIM signatures.
  • Changing the envelope domain, that is, from: domain name, without updating corresponding records.
  • Sending emails from a subdomain that is not authorized.
  • How to Troubleshoot DMARC Authentication Failures

    DMARC authentication failures can be challenging to solve since several factors could be responsible for that. Below are the six steps to troubleshoot DMARC authentication failures:

    Step 1: Check DMARC Aggregate Report

    The DMARC aggregate reports provide a statistical view of the email traffic and the messages passing DMARC authentication checks. These reports show what parts of the messages failed, if any, in case of DMARC failures. You need to check these reports and identify where the problem occurs.

    Step 2: Investigate SPF and DKIM

    The next step is to check the SPF and DKIM settings for your domain. You need to verify that your DKIM and SPF algorithms are working correctly. Here’s how to investigate SPF and DKIM:

  • SPF: Open a terminal and input this command: dig txt (your domain name) +short. Ensure that your SPF record lists every IP address or server that can send emails that are identified as your domain.
  • DKIM: You can use DKIM Analyzer to check that your emails are signed correctly.
  • Step 3: Check DNS settings

    Ensure that your DNS settings have the correct information for both SPF and DKIM records. Your DNS record should indicate that you are the owner of a specific domain.

    Step 4: Check Email Headers

    Check the email header to determine the sender of the email if it comes from a legitimate sender. Email senders have to identify the sender address on the mail header.

    Step 5: Monitor DMARC Reports

    Monitoring your DMARC reports is essential to identify DMARC authentication failures promptly. You need to check to see authorized sends, detect the number of failed messages, and identify which sector and mailbox provider the failed messages relate to.

    Step 6: Check email infrastructure

    You should check your email infrastructure, including your email SSL certificate, mail server, and routing configurations, to ensure that there is no mismatch between the IP address and the authorized sender. Double-checking your email infrastructure is essential because it can solve DMARC authentication failures.


    Identifying and resolving DMARC authentication failures is critical to ensuring email deliverability, enhancing email security, and maintaining your brand’s email reputation. By checking DMARC aggregate reports, investigating SPF and DKIM, monitoring DMARC reports, checking email headers, checking DNS settings, and examining email infrastructure, you should be able to troubleshoot DMARC authentication failures quickly and efficiently. Access this recommended external website to discover extra and complementary information about the topic covered. We’re committed to providing an enriching educational experience. dmarc checker.

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