Clients unable to get DHCP address through WLC from DHCP Server

Unanswered Question
Aug 15th, 2008
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OK we are running old code 4.0.179 and I have read a lot of articles in this forum about the problems with 4.0.179 but I don't wish to jump and upgrade all our 17 WLCs at 8 sites if I don't have to immediatly, because the word UPPGRADE has to be signed by God's God at this site.

This customer has been running fine for several months without any trouble, but once in Feb 2008 and once in Aug 2008 they had the following problem in atleast 5 or 6 of the 8 sites.

The only way to recover from this problem is to reboot the WLC 4404 units. Nothing else gets us out of this problem.

Tracing packets have shown the DHCP response reaches the WLC from the DHCP Server but the WLC does not send the response to the client.

Hand held Teklogix clients and even Laptops using WPA2/PKC when rebooted failed to acquire DHCPP address from an external DHCP Server but all clients which already have DHCP addresses (meaning not rebooted) will work fine.

In the case in Aug 2008 the problem was triggered at one site by the port-channel ports on a Catalyst 3750 connecting to the WLC, flapping.

In the case in Feb 2008 the problem was triggered by a very trivial config change in all the 8 x WLC 4404. This config change was just the password change on all the 8 WLC 4404.

A second problem is when Teklogix Hand Held clients roam the re-authentication goes all the way to the ACS Server rather than be done by the WLC.

If there is no other solution other than upgrade, of course I will request customer to do that. But is there someting that we overlooked. Why the problem got triggered by a simple configured change on the WLC such as password change.

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Overall Rating: 5 (1 ratings)

Upgrading may not be the solution to your problem.

I am running 4.2.130 on my local controllers, and am forced to run 4.2.99 on my anchor DMZ for the same reason as you.

WHen I upgrade my anchor to 4.2.130 the DHCP server sees the requests, issues an address but the local WLC does not pass it on (this is seen with DHCP drop messages in the debug output)

Wed Jul 9 10:10:26 2008: 00:1a:73:9d:96:cb DHCP dropping REPLY from Export-Fore ign STA

agroarke Sun, 10/05/2008 - 06:00
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I do not know the answer to this but I have a similar problem using 4404 Clients initially get an ip address from the remote dhcp server but when I try and renew the lease from the client (ipconfig /renew) the client hangs. Thus when the client switches off their machine when it reboots it does not get a response to the dhcp request seems as though the controller is eithe not forwarding the requests or replying when DHCP server responds (Not got yhe equipment to test This) Any ideas?


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