Hi,
I recently performed troubleshooting of the same issue in two different Active Directory forests in a short period of time, and would like to investigate the root cause.
The following is true for both environments:
Wireless clients: Windows 7 Enterprise with SP1
NPS Server: Windows Server 2008 R2 Standard with SP1
Domain Controllers: Mix of Windows Server 2003 R2 Standard SP2 and Windows Server 2008 R2 Standard with SP1
Certification Authorities: Single-tier CA running Windows Server 2008 R2 Standard with SP1
Wireless authentication: "EAP: Microsoft Smard Card or other certificate"
The problem was wireless clients suddenly being unable to connect to the wireless network, without any known changes being made to the infrastructure.
In the WLAN-Autoconfig eventlog on the client computers we received the following event:
Event ID 8002 — 802.11 Wireless Connectivity
http://technet.microsoft.com/en-us/library/cc735927(v=ws.10).aspx
The reason code we received is not mentioned in the article: "Explicit EAP failure received".
In the first case I went through a few hours of troubleshooting on a client that was also connected to the network through a wired connection.
I used Network Monitor to investigate, and saw that the client sent several "EAP Request, Type=PEAP", and received "EAP:Failure" after 5 retries.
Using Network Monitor on the NPS server I also saw EAP Requests and Responses which ended with "EAP: Failure" in the end.
The issue was resolved by changing EAP Types on both the NPS Server and in the client settings (using GPO) from "Microsoft: Protected EAP (PEAP)" to "EAP: Microsoft Smard Card or other certificate".
In the second event in the other environment the problem was resolved by rebooting the NPS server.
I know it`s hard to troubleshoot a problem that has been resolved, but what I`m looking for is basically the possible reasons for the "Explicit EAP failure received", and some guidelines on how to troubleshoot the issue if it occurs again.
Jan Egil Ring
Blog: http://blog.powershell.no
Twitter: http://twitter.com/janegilring