Question : Problem: PEAP authentication problems with Cisco Wireless

Hi,
We have just purchased a cisco WLC 4402 with Cisco 1252 LWAP's
We have an existing Cisco ACS server running version 3.3 that we use for TACACs authentication for existing network devices. This authenticates into AD and has been working fine for ages.
i am trying to set up a wireless network. We have done the basics and set up the WLC to connect to a cisco switch which connects to the ACS, this is all ok. The WLC is configured with one wireless vlan. We connected one AP ti the WLC and it all works fine. WIreless PC with no authentication connects to the AP, WLC etc. We can access the network and all works fine. The part we are struggling with is the Username password authentication  and encryption settings to run PEAP with Chap username and passwords.So far i have not managed to find any Doco's on this type of setup.

Answer : Problem: PEAP authentication problems with Cisco Wireless

If your client keeps getting the message attempting to authenticate you probably need this hotfix from Microsoft.  We had this issue as well and it was the answer our problem.

http://support.microsoft.com/kb/885453/en-us