Troubleshoot 802.1X Client Connection Issues

by Eric Geier [Published on 17 Nov. 2011 / Last Updated on 17 Nov. 2011]

Checklist for fixing 802.1X connectivity problems.

Here are items to check when having problems with 802.1X clients, wired or wireless with WPA/WPA2-Enterprise encryption:

  • Client Settings: First double-check all client settings in Windows. Verify the EAP-PEAP or EAP-TLS (Smart Card or Certificate) settings. Plus make sure the RADIUS server’s CA certificate is installed and selected. In Windows 7, click the Advanced settings button on the Security tab of the wireless network properties and verify the settings.
  • RADIUS Server: Check the authentication server for any issues, including connections to the user and any other database. Check the server logs or debugging details for any clues.
  • Access Point or Switch: If there are issues with all clients connecting through a particular AP, verify its settings. Verify the IP address is set to a static address and it corresponds with the correct Shared Secret setup on the RADIUS server.
  • General Network Issues: The underlying problem can be a general networking issue, such as an 802.11b or g client that’s not compatible with an 802.11n AP even though the standards are supposed to be interoperable. Some wireless adapters might also not support WPA or WPA2. Try updating the driver for the wireless adapter and install Windows updates.
  • User Settings and Attributes on RADIUS Server: Verify any settings or custom attributes for the user on the RADIUS isn’t causing problems.
    Perform Tracing and Review Client Logs: You can use the netsh ras commands in Windows XP or netsh wlan commands in Windows Vista and later to help troubleshoot the issue.

See Also

The Author — Eric Geier

Eric Geier (Dayton, Ohio) is a Freelance  Tech Writer and Author specializing in computer networking. He's also the Founder and Owner of NoWiresSecurity, which provides a hosted cloud-based RADIUS service to help businesses easily secure their Wi-Fi networks with the Enterprise (802.1X) mode of WPA/WPA2 security. He’s also the Founder and Owner of On Spot Techs, which provides on-site computer and technology services.

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