Intel DHCP Issue

Unanswered Question
May 21st, 2010
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We're running into a very weird, intermittent DHCP issue with Intel wireless cards.  The two cases I distinctly remember have been with the 3945ABG and 5100 cards able to authenticate/associate, but could not pull an IP address (just 169's).

We are running 2 SSIDs - one secure, one open.  The secure uses WPA-TKIP & WPA2-AES with PEAP.  The APs are lightweight 1231's.

The client we ran into today had a 169 while connected to the secure SSID using an Intel 5100.  I connected to the open SSID with no problems, but going back to the secure resulted in the same issue - successful association/authentication, but no IP.  Checking the DHCP logs from the DHCP server showed no reqeusts or acknowledgements after multiple successful connections to the open SSID and multiple unsuccessful connections to the secure SSID.  I also noticed an abnormal amount of "Decrypt Failed" entries in the client details.

I also should note that the laptop we were using (not the troublesome client laptop) had an Intel 3945abg that connected to the secure and open SSID just fine upon arrival.

I was able to connect to the secure SSID on the client laptop by using a USB wireless adapter, but not with the built in Intel 5100.

Finally, we decided to reboot the AP and the troublesome client was able to pull a valid IP and all was well.  Has anyone else ran into a simlar issue?

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Peter Nugent Fri, 05/21/2010 - 16:57
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Its apparently common to uese two encryption protocols on the same WLAN however it is not best practice.

Try with either just WPA or WPA2 and see if it is any better. Client cards can get confused when they have to decide which to take


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