Clients try to connect to hidden SSID

Unanswered Question
Mar 23rd, 2010


I have encountered a strange behavior lately were in a building with 14 floors, when in each floor there are at least 2 AP's (1131AG), which are connected to a WiSM module at different location (working mode is H-REAP).

clients running WinXP can connect to the SSID (Which is hidden and using 802.1x EAP-TLS) at each floor except floors 2 and 3.

I have sniffed the air and done some debug but i can't see any reason for this behavior, anyone has an idea?

Best Regards,

Tal Madari

I have this problem too.
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talmadari Wed, 03/24/2010 - 01:15

Tha AP's are configured in groups.

One more thing - this issue occurs only with Windows XP clients, when trying with windows 7 it work's fine!

Scott Fella Fri, 03/26/2010 - 05:01

Okay... so these Windows XP devices that cannot connect to thoses two floors, are they devices you know of and you have tested them to work fine in the other floors?  Also verified the wireless profile set on the client?  The only reason I ask, is that if the same devices work on other floors and the AP on the same building connect back to a WLC via h-reap, then I don't know why that would happen especially if the Windows 7 devices are connecting fine to the same SSID.  Can you tell use more what you have tried to pinpoint the issue.

talmadari Tue, 04/06/2010 - 06:45

Well here are my test resualts:

- SSID is hidden on all floors

- Windows XP can't connect on floor 2 and 3 but CAN connect on floors 4 to 13

- Windows 7 can connect on any floor

- When broadcasting the SSID, Win XP can connect also on floors 2 and 3

- There are some wireless networks around the building which can be noticed when i'm in floors 2 and 3

I'm suspect that due to enviroment interference and/or neighboor WLAN's the Win XP clients can't "see" clearly the hidden SSID and "hear" much loader the neighboor WLAN's.

Scott Fella Tue, 04/06/2010 - 07:38

Have you taken an XP machine that works on the other floors to the 2nd or 3rd floor?  The reason I asked is that if WIndows 7 or other non XP devices work fine, then it looks like an issue with the configuration on the XP machines.  But might not be.  Review the configurations on the device on the 2nd and 3rd floor, make sure you have the check box checked that allows to connect with hidden ssid.  If you had interference with other wifi in the area or general interference, you would have issue with other devices not just Windows XP.  You using both 2.4ghz and 5ghz on all the floors?

amr.momtaz Thu, 05/06/2010 - 02:12


Are all the APs registered with the same controller ? (this is very important to continue the troubleshooting)

What are the security settings for the SSID?

What is the difference between the laptops that are running windows 7 and windows xp ?

Could be a problem with the L2 encryption, I had a similar problem, the clients were connecting to the APs in the floor above them, after some troubleshooting, it turns our that the APs in the above floor were broadcasting the same SSID but with higher encryption WPA2 (and windows by default will try and connect to the more secure SSID).

Could be that client cards support only WPA and not WPA2.

Let me know the answers to the above questions and I will try and troubleshoot with you.


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