APs take 3 hours for IP

[kkonuru123]

Dear Techies....

I have a problem in Wirelesss....If I reboot coreswitch or firewall or unplug or replug the WLC cable....means disturbance to WLC, entire APs will go down.

APs are having DHCP IPs...when we check on DHCP server there are no requests on APs vlan and is empty.

APs are not getting DHCP IP address.

After 3 hours APs will come up automatically.

how to check & where could be the problem ?

[Leo Laohoo]

Put a PC/Laptop into the same VLAN as the APs.  Does the issue occur with the PC/Laptop?

[kkonuru123]

Thanks, I did connect last time as there was no official laptop. 

During next outage, I will connect and check it  ;-)

[mohanak]

• The client is either unable to get an IP address or encounter delay in getting the IP address through DHCP. The debug dhcp on the controller indicates this:

  Sun Nov 9 22:09:05 2008: <mac address of the client> DHCP processing DHCP NAK
  

  DHCP NAK is usually sent by the DHCP server to indicate an attempt by the client to obtain an IP address from the subnet to which it does not belong. This usually occurs when a client roams from one WLC to another, where the same WLAN is assigned a different VLAN.

  Configure the DHCP proxy on the WLC to provide a fix for this.

[kkonuru123]

Thanks for the reply. I have disconnected one access point from the wall and connected to the switch port in the same AP vlan and noticed that the logs shows unable to reach DHCP server.

Tomorrow I will check it DHCP proxy is enabled or not. It should be enabled since I didnt do any changes and in the previous backup config it has.

Even WLC, AP reboot also didnt work. Somewhere this 3 hours was defined, unable to understand, after 3 hours it is coming up automatically.