Regarding Cisco 3700 are not getting ip from DHCP Server and Stuck in Discovery mode

[manzeel]

Hello, Need your assistance.

I have around 30 cisco 3700 Series AP. Recently i have upgraded to WLC firmware to 8.2.141.0. After upgrade my half of the aps are not able to join controller. When i console to ap, I found the ap are not getting ip from DHCP Server- although they are in discovery mode for IP. I statically configure ip from CLI but still i am not able to ping its gateway as well ping WLC Mgmt IP. I performed reset for some AP and reconfigured with static ip but still there is no luck of pinging its gateway. However, when connect laptop to same port, I can get ip from DHCP Server. I searched in forum and asked here and there but still not able to pin-point root cause. yours help will be greatly appreciated.

Thanks in Advance.

 

[Philip D'Ath]

How do they connect to the network?  Power injector?  What sort of switch are they plugging into?  Anything appear in that switch log?  What config do you have on the switch port?

What is doing DHCP for the network?

If you take one that is not working and plug it into the port of another that is working - does it start working then?

[manzeel]

Hello Philip,

Ap are using Power Injector to connect to Network. I am using either Cisco or Avaya switch. In switch there is not much log as port is up and mac is learned and I have configured as access port. DHCP is used to connect Wired Lan Networks which are in default vlan. Yes, when I changed to port than Ap is working. Initially where my AP are connected there is no ports available so I connected by bring to another floor than it is working. In my building, there are around 10-12 manageable switch and each switch there is at least 2 Ap where 1 AP connected to WLC other in discovery mode for IP.

[Philip D'Ath]

What configuration are your using for a Cisco switch port connecting to an AP (particularly one that is not working)?

[manzeel]

Yes there is address Scope left  I did not not made any changes in AP-Port in Switch.It is in access port of default vlan. 

[Philip D'Ath]

You haven't provided what  I have been asking for.  Please show the actual switch port configuration.  What model Cisco switch are you using?

[manzeel]

Dear Philip,

All my Access-point is configured in access in Respective Switch Port. I do not have access to switch at this moment but i am pretty sure that respective switch port does not have un-necessary config.   I have Cisco 2900 and Avaya 3000 Series Switch.

[Philip D'Ath]

Does the DHCP server have free space in its scope?  Are you sure you have not run out of DHCP addresses?

[William Kuczmera]

What Discovery Method are you attempting to use ? 

L2 Broadcast 

L3

OTAP

DNS

Of the 4 I prefer DNS as it is the easiest to work with. The attached post calls it out for you. 

I think if you create a DNS statement your APs you will be good to go. 

https://supportforums.cisco.com/document/95736/lightweight-ap-discovery-process-wireless-lan-controllers

The AP can discover controllers through your Domain Name System (DNS) server. The DNS server must be configured to return controller IP addresses in response to CISCO-LWAPP-CONTROLLER.local domain.

William Kuczmera 

[manzeel]

Dear William,

Due to certain security measures placed, i am Manually pointing to WLC from respective AP. My problem is that after WLC firmware update and reboot my ap are not able to get ip though DHCP Server nor able to reach its static configured gateway from ap.

[anumpand]

Hi,

Were you able to resolve the issue? If yes, then how?