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Cisco 2504 WLC - external dhcp issue


I am having a problem getting a DHCP IP address when connecting to a Cisco 3502 LWAP which is connected to a Cisco 2504 WLC.

The WLC is in the same subnet as the DHCP server (Windows 2008 server) and the AP 3502 is in a different network.

I can ping from the AP to the WLC etc and I have SSH access to the WLC.

I can see the SSID fine and I can see that the AP has registered with the WLC but I just dont get an IP address.

We have been up until now just using autonomous AP (Linksys mostly) and this is the first LWAP I am deploying so I am flying a bit blind. I have read lots of different Cisco articles but I seem to be going round in circles so I would greatly appreciate any help.

The autonomous AP's are on the same network as the new AP 3502 and they dont have any problem getting an IP address from the same DHCP server but they are not connected via the WLC of course.

I primed the AP 3502 with a static IP address of the controller so I am niot sure if that is an issue. I only have 1 x AP, 1 x WLAN & 1x SSID so the config is pretty basic. I have configured the DHCP IP address against the management interface and have checked Enable DHCP Proxy...

I have had a look on the DHCP server and setup a Vendor class for Cisco AP c3500 etc although this was a bit confusing and I am not sure whether I have got this bit right.If anyone can point me to any documentation that is a bit clearer that would be appreciated.

thanks , Peter.

Community Member

Cisco 2504 WLC - external dhcp issue


Peter did you make the virtual interface that belong from the client VLAN and give this virtual interface a IP and DHCP Address.

Cisco 2504 WLC - external dhcp issue

Hi Peter,

Some assumptions --

1. You can ping your access point and its on the WLC based on your comments.

2. You can see your SSID, but what security are you using? I would leave it as OPEN for our testing

3. On your WLAN SSID which interface are you mapping it to. If you click on your WLAN you can see the mapping.

4. On the CONTOLLER TAB the interface (wired side) is where your wireless traffic meets your wired traffic. Did you enter in your DHCP server info there?

5. Assumption you cant get an IP over the wireless. ..

"Satisfaction does not come from knowing the solution, it comes from knowing why." - Rosalind Franklin
Community Member

Cisco 2504 WLC - external dhcp issue

Thanks Stefan,

I have this working now...

As the WLC was originally connected to a different network than the AP I am guessing  that to make this set up work I probably needed to configure a Dynamic  Interface with an IP address in the same network as the AP to get the  dhcp-helper to work properly?

Anyway I decided to simplify the setup and I am intending to now leave it this way.

I was using certificates to authenticate (eap-tls) to a radius server and initially I wasn't sure whether the problem was with authentication or with getting an IP address allocated. I did some testing and changed the authentication to WPA & PSK and this authenticated but I did not get allocated an IP address.

I then decided to move the WLC onto the same network as the AP (we already have ip-helper configured and working on this segment for the older Linksys AP's) and that sorted out the DHCP issues I was having and everything is now working.

regards, Peter

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