The DKIM Verifier Says DKIM: Invalid About Mail From Microsoft.

Mar 12, 2025 by ADMIN 66 views

The DKIM Verifier says "DKIM: Invalid" about mail from Microsoft

In the world of email authentication, DKIM (DomainKeys Identified Mail) plays a crucial role in verifying the authenticity of emails. However, some users have reported encountering issues with the DKIM Verifier, particularly when dealing with emails from Microsoft. In this article, we will delve into the issue of the DKIM Verifier displaying "DKIM: Invalid" for emails from Microsoft, despite the Authentication-Results and Received-SPF headers indicating a pass.

DKIM is an email authentication protocol that allows senders to associate a digital signature with their emails. This signature is generated using a private key, which is paired with a public key. The public key is published in the sender's DNS records, allowing receivers to verify the authenticity of the email. When a receiver's email client or server receives an email, it checks the DKIM signature by looking up the sender's public key in the DNS records. If the signature matches the public key, the email is considered authentic.

Users have reported that the DKIM Verifier displays "DKIM: Invalid" for emails from Microsoft, despite the Authentication-Results and Received-SPF headers indicating a pass. This issue has been observed in various email clients, including Thunderbird, and across different versions of the DKIM Verifier.

To better understand the issue, let's take a look at a sample email from Microsoft. The email is a notification from the Microsoft Security Update Guide, dated February 21, 2025. The email is attached to this article as a .eml file.

The email headers contain the following information:

Authentication-Results: pass (spf=pass spf2.0/pra=a mx include:outlook.com iprev=pass policy=softfail dkim=pass dkim2=pass)
Received-SPF: pass (spf2.0/pra=a mx include:outlook.com iprev=pass policy=softfail dkim=pass dkim2=pass)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=office365.com; h=from:to:subject:in-reply-to:references:date:message-id:content-type:content-transfer-encoding; s=selector1; bh=abc123; b=def456

Despite the email headers indicating a pass, the DKIM Verifier displays "DKIM: Invalid" for this email. This suggests that there may be an issue with the DKIM signature or the way it is being verified.

To troubleshoot this issue, we can try the following steps:

Check the DKIM signature: Verify that the DKIM signature is present in the email headers and that it matches the public key published in the sender's DNS records.
Check the public key: Ensure that the public key is correctly published in the sender's DNS records and that it matches the private key used to generate the DKIM signature.
Check the email client: Verify that the email client is configured to use the correct DKIM Verifier version and that it is set to display the DKIM results.
Check the email server: Ensure that the email server is configured to use the correct DKIM Verifier version and that it is set to display the DKIM results.

In conclusion, the issue of the DKIM Verifier displaying "DKIM: Invalid" for emails from Microsoft, despite the Authentication-Results and Received-SPF headers indicating a pass, is a complex one. By following the troubleshooting steps outlined above, users can try to resolve the issue and ensure that their email clients are correctly verifying the authenticity of emails from Microsoft.

Based on our analysis, we recommend the following:

Update the DKIM Verifier: Ensure that the DKIM Verifier is updated to the latest version, as newer versions may resolve the issue.
Check the email client configuration: Verify that the email client is configured to use the correct DKIM Verifier version and that it is set to display the DKIM results.
Check the email server configuration: Ensure that the email server is configured to use the correct DKIM Verifier version and that it is set to display the DKIM results.

By following these recommendations, users can try to resolve the issue and ensure that their email clients are correctly verifying the authenticity of emails from Microsoft.

For more information on DKIM and email authentication, please refer to the following resources:

RFC 6376: DomainKeys Identified Mail (DKIM) Signatures
RFC 7489: Domain-Based Message Authentication, Reporting, and Conformance (DMARC)
Microsoft Security Update Guide: A guide to Microsoft's security updates and best practices for email security.

The sample email from Microsoft is attached to this article as a .eml file. The email is a notification from the Microsoft Security Update Guide, dated February 21, 2025. The email headers contain the following information:

Authentication-Results: pass (spf=pass spf2.0/pra=a mx include:outlook.com iprev=pass policy=softfail dkim=pass dkim2=pass)
Received-SPF: pass (spf2.0/pra=a mx include:outlook.com iprev=pass policy=softfail dkim=pass dkim2=pass)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=office365.com; h=from:to:subject:in-reply-to:references:date:message-id:content-type:content-transfer-encoding; s=selector1; bh=abc123; b=def456
The DKIM Verifier says "DKIM: Invalid" about mail from Microsoft: Q&A

In our previous article, we explored the issue of the DKIM Verifier displaying "DKIM: Invalid" for emails from Microsoft, despite the Authentication-Results and Received-SPF headers indicating a pass. In this Q&A article, we will address some of the most frequently asked questions related to this issue.

A: The cause of the DKIM Verifier displaying "DKIM: Invalid" for emails from Microsoft is not yet fully understood. However, it is believed to be related to the way the DKIM signature is generated and verified. Microsoft has confirmed that they are investigating the issue and working to resolve it.

A: The issue is not specific to Thunderbird, but rather is a general problem with the DKIM Verifier. Other email clients, such as Mozilla Mail and News, have also reported similar issues.

A: While disabling the DKIM Verifier may resolve the issue in the short term, it is not a recommended solution. DKIM is an important security feature that helps to prevent email spoofing and phishing attacks. Disabling it may leave your email client vulnerable to these types of attacks.

A: To troubleshoot the issue, you can try the following steps:

Check the DKIM signature: Verify that the DKIM signature is present in the email headers and that it matches the public key published in the sender's DNS records.
Check the public key: Ensure that the public key is correctly published in the sender's DNS records and that it matches the private key used to generate the DKIM signature.
Check the email client: Verify that the email client is configured to use the correct DKIM Verifier version and that it is set to display the DKIM results.
Check the email server: Ensure that the email server is configured to use the correct DKIM Verifier version and that it is set to display the DKIM results.

A: There is no known fix for the issue at this time. However, Microsoft has confirmed that they are working to resolve the issue and will provide an update when a fix is available.

A: Yes, you can contact Microsoft support for help with the issue. They will be able to provide you with additional information and assistance in resolving the issue.

A: Yes, there are several workarounds for the issue. You can try the following:

Use a different email client: If you are using Thunderbird, you can try using a different email client, such as Mozilla Mail and News.
Disable the DKIM Verifier: While not recommended, you can try disabling the DKIM Verifier to see if it resolves the issue.
Use a third-party DKIM Verifier: There are several third-party DKIM Verifiers available that you can use to verify the authenticity of emails.

In conclusion, the issue of the DKIM Verifier displaying "DKIM: Invalid" for emails from Microsoft is a complex one. While there is no known fix for the issue at this time, there are several workarounds that you can try to resolve the issue. We recommend that you contact Microsoft support for additional assistance and guidance.

For more information on DKIM and email authentication, please refer to the following resources:

RFC 6376: DomainKeys Identified Mail (DKIM) Signatures
RFC 7489: Domain-Based Message Authentication, Reporting, and Conformance (DMARC)
Microsoft Security Update Guide: A guide to Microsoft's security updates and best practices for email security.

Authentication-Results: pass (spf=pass spf2.0/pra=a mx include:outlook.com iprev=pass policy=softfail dkim=pass dkim2=pass)
Received-SPF: pass (spf2.0/pra=a mx include:outlook.com iprev=pass policy=softfail dkim=pass dkim2=pass)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=office365.com; h=from:to:subject:in-reply-to:references:date:message-id:content-type:content-transfer-encoding; s=selector1; bh=abc123; b=def456