cannot obtain ip address from external DHCP server through WLC

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Oct 3rd, 2007
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cannot obtain ip address from external DHCP server through WLC


as I wrote on the title of the request I have a problem with a new Mesh LAN.I've got 1 RAP and 2 MAP that receive the ip address from an external DHCP server (which is on the same ip subnet as WLC), when using internal WLC DHCP server to distribute ip addresses to Wireless clients all works fine.

The problem is when i try to get ip addresses from external dhcp server (that is on the same ip subnet) through WLC.As well if I statically config a static ip address on the Wireless client it cannot surf the network, it seems that the packets don't pass through the WLC.We have also tried to configure the DHCP option 82 without any success.

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leon.mflai Tue, 10/09/2007 - 09:23
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Have you setup "virtual interface =" in the WLC? ....It is essential for forwarding DHCP request to ext. DHCP server. Pls rate if helpful!

fcoppotelli Tue, 10/09/2007 - 23:39
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Yes, I configured it with the ip address without success.I think that I should use 2 different VLANS (one for the manageent and one for the WLAN clients).All my tests using just one VLAN for the APs and for the clients were a failure.

leon.mflai Wed, 10/10/2007 - 09:05
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Have you studied the log or Ethereal capture if there is any DHCP request transmitted from WLC to your external DHCP server for single VLAN case?

I am interested if there is no DHCP request generated from WLC for single VLAN case.

s.henrot Wed, 06/18/2008 - 05:11
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I have the same problem, did you find something to help me ?

jeromehenry_2 Wed, 06/18/2008 - 05:43
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Can you ping your DHCP server from the controller? Is the DHCP server defined in the interface you send your users through?

dennischolmes Thu, 06/19/2008 - 11:08
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try going to the CLI on the controller and typing this command: config dhcp proxy disable

This will disable dhcp by proxy so that the client dhcp requests are coming from the client and not the virtual interface. This method is not supported by some dhcp servers. Also make sure that the MAC address of each AP is added in the mac filtering section of the WLC. Without the AP could register briefly but not pass traffic to the network as it has not been validated as an internal AP. This is part of the zero touch configuration policy.


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