Hi, I'm not sure if this is an issue with Cisco or Microsoft or the Vendor of the hardware. This is my issue:

We're using Cisco 2500 Series Wireless Controller and our AP's are all Cisco AIR-CAP2602I-A-K9. Instead of using the WLAN controller's DHCP, we decided to use MS DHCP(a Windows Server 2003 SP2 x86) server. Our scope for this has a subnet of 255.255.252.0 (746 usable IP's - pls correct me if this is wrong). 3-days lease for wifi IP

Form of Auth: via a RADIUS server WPA2-Ent, AES

So the wifi has been working fine, I can see wireless devices working fine i.e laptops, iphones, and ipads. All of them are working fine on the internet, they can even perform file sharing and any network related activity. I noticed that there's an issue in some laptops, they've been using the wifi before and was successful but suddenly they just experienced limited connection (unauthenticated) but the weird thing is this computer did acquire a dhcp address together with all network settings like gateway, dns.

I did some research regarding this issue like doing t/s on windows like reinstalling wlan driver, performing tcp/ip reset, etc but unfortunately unsuccessful. So I doubted that since we have a lot of users, the dhcp might be full but apparently, we still have 200+ available IP's

Is there something I need to check with the controller and AP's? since I've checked on the Windows side?

FYI, we also doubted that the OS might have something to do with this issue since it has been used for quite some time, so we reformatted the unit to ensure that the user has a fresh installed OS but still same results.

Regards,

Jeff