In today's world of cyber threats, email remains as one of the most common attack vectors. With an increase in the number of business transactions and sensitive information being shared over emails, it is vital to have proper email security measures in place. One of the widely used security measures is DMARC, which helps in preventing email spoofing and phishing attacks. However, many organizations that use Mimecast for email security often face a common issue – a DMARC failure. In this blog post, we'll explore the causes behind this issue and provide you with solutions to address it.
DMARC Fail Mimecast Table of Contents
Understanding DMARC and Mimecast
DMARC (Domain-based Message Authentication, Reporting, and Conformance) is an email authentication protocol that helps in combating email spoofing by allowing domain owners to specify policies for handling unauthenticated emails. DMARC builds upon two other email authentication mechanisms: SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail).
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Mimecast, on the other hand, is a popular email security service that provides various features, including spam filtering, archiving, and email continuity. Mimecast often performs the role of an email gateway, processing inbound and outbound emails for organizations.
Why DMARC Failures Occur in Mimecast
There can be multiple reasons for a DMARC failure in Mimecast. Some common causes include:
1. Modification of DKIM Signature
Mimecast may modify the email content (e.g., adding a disclaimer or converting URLs to point to their URL protection service) which can invalidate the original DKIM signature. This can result in a failed DMARC check.
2. Alignment Issues
For a DMARC check to pass, either SPF or DKIM must validate, and the sender's domain must be aligned with the domain in the email header's 'From' field. If the domain alignment is missing, DMARC will fail.
3. Incorrect or Missing SPF Record
If the SPF record is not set up correctly or is missing for the sending domain, it can cause DMARC authentication to fail.
Troubleshooting DMARC Failures in Mimecast
For organizations facing DMARC failures with Mimecast, here are some steps you can take to resolve the issue:
1. Set up a DMARC Record
If you haven't already set up a DMARC record, start by creating a DMARC policy for your domain. Ensure that it contains the correct information, including SPF and DKIM authentication.
2. Review and Correct SPF Configuration
Check your domain's SPF configuration and make sure it includes all legitimate sending IP addresses and 3rd party providers (such as Mimecast) authorized to send emails on your behalf. Also, ensure that the SPF record adheres to the 10 DNS lookup limit.
3. Allow Mimecast to Sign Outbound Emails with DKIM
To prevent the DMARC failures caused by DKIM modification, you can configure Mimecast to sign outbound emails with its own DKIM signature. This will ensure that the emails remain authenticated even when the content is modified.
4. Monitor DMARC Reports
Regularly review and analyze DMARC reports to identify any patterns of failed authentication and potential malicious activity. Detecting and addressing such issues quickly will improve your overall email security.
DMARC Fail Mimecast Example:
Imagine your organization uses Mimecast for email security and DMARC authentication is failing consistently, leading to delivery issues, a high spam score, and increased phishing risks. After reading this guide, you realize that Mimecast is adding a disclaimer to the emails, causing the original DKIM signature to get invalidated. As a solution, you could configure Mimecast to sign outbound emails with its own DKIM signature, thereby resolving the DMARC authentication issue and securing your organization's email infrastructure.
Understanding the causes behind a DMARC failure in Mimecast and taking appropriate corrective measures can significantly enhance your organization's email security. By staying vigilant and proactively addressing authentication failures, you can protect sensitive information and maintain a secure and trusted email environment.
If you found this article helpful, please feel free to share it with your peers and explore other guides on Voice Phishing to be better prepared in your fight against cyber threats.
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NordPass
Enhance your digital safety with NordPass, a powerful tool in our affiliate network. NordPass is a reliable password manager designed to simplify security. It not only stores but also organizes and safeguards your passwords, offering seamless access across devices. It's the hassle-free solution to maintaining strong, unique passwords – a crucial step in combating phishing and cyber threats. Trust NordPass to fortify your online defenses, and experience cybersecurity made easy.
