Fixing EAP-TLS Authentication Issues on Windows Devices Using ISE

Key Notes

  • Clear registry entries that may block authentication.
  • Modify validation settings to ensure compatibility.
  • Contact support if issues persist despite troubleshooting.

Resolving EAP-TLS Authentication Failures on Windows 11 with Cisco ISE

EAP-TLS authentication failures can disrupt network access security mechanisms, especially when paired with Cisco ISE and Windows 11. This guide details actionable steps for resolving these issues effectively.

Effective Troubleshooting Steps

When encountering Event 5400 – an authentication failure during EAP-TLS processes, try the following solutions:

  1. Clear unnecessary registry entries.
  2. Modify the settings for certificate validation.
  3. Reach out to Microsoft Support for additional guidance.

Let’s discuss each method in detail.

Step 1: Clear Unnecessary Registry Entries

This issue often arises from incorrect selections of Root and Intermediate certificates by Group Policy. To resolve this problem, you’ll need to remove specific registry keys. Before you proceed, back up your registry settings. Then, follow these steps:

Launch Command Prompt as an administrator and enter the following commands: 

 reg delete "HKCU\Software\Microsoft\Windows\CurrentVersion\Policies" /f reg delete "HKCU\Software\Microsoft\WindowsSelfHost" /f reg delete "HKCU\Software\Policies" /f reg delete "HKLM\Software\Microsoft\Policies" /f reg delete "HKLM\Software\Microsoft\Windows\CurrentVersion\Policies" /f reg delete "HKLM\Software\Microsoft\Windows\CurrentVersion\WindowsStore\WindowsUpdate" /f reg delete "HKLM\Software\Microsoft\WindowsSelfHost" /f reg delete "HKLM\Software\Policies" /f reg delete "HKLM\Software\WOW6432Node\Microsoft\Policies" /f reg delete "HKLM\Software\WOW6432Node\Microsoft\Windows\CurrentVersion\Policies" /f reg delete "HKLM\Software\WOW6432Node\Microsoft\Windows\CurrentVersion\WindowsStore\WindowsUpdate" /f

Please ignore any messages stating “ ERROR: The system was unable to find the specified registry key or value. ” after executing these commands. After clearing the entries, restart your computer and reselect the necessary certificates.

Step 2: Alter Certificate Validation Settings

In earlier versions of Windows, such as Windows 10, validation for server certificates operated under different methodologies depending on the EAP type used. However, Windows 11 has streamlined these validations to align with the WPA3-Enterprise standards. If your EAP-TLS setup is encountering issues with TLS 1.3, ensure your RADIUS server is fully updated. Alternatively, consider disabling TLS 1.3 on the server end. Additionally, verify that the root and intermediate certificates used by the ISE server are properly trusted by the Windows 11 machine.

Step 3: Contact Microsoft Support

If the above methods do not resolve the issue, consider reaching out to Microsoft Support for further assistance. Visit support.microsoft.com, log into your account, and submit a request stating the details of your authentication dilemma.

Summary

This guide provides crucial troubleshooting measures for addressing EAP-TLS authentication failures on Windows 11 systems when using Cisco ISE. Through registry clearance, certificate validation adjustments, and the option to engage Microsoft Support, these methods aim to restore seamless network access.

Conclusion

By implementing the troubleshooting steps discussed, you can effectively tackle EAP-TLS authentication failures on Windows 11. Addressing these issues is crucial for ensuring secure network access through Cisco ISE, promoting a reliable network environment.

FAQ (Frequently Asked Questions)

What is EAP-TLS?

EAP-TLS is an authentication protocol that uses a client and server-side certificate combined with Transport Layer Security (TLS) for secure connectivity in network access scenarios.

Why does Event 5400 indicate an authentication failure?

Event 5400 suggests that the authentication attempt using EAP-TLS did not complete successfully, which can result from issues such as invalid certificates or misconfigured settings.