topic Re: WLC option 43 in Wireless

WLC option 43

Nub65 — Mon, 05 Jul 2021 18:37:01 GMT

Hello,

Can anyone explain to me if you need dhcp option 43 when you have your access point in the same vlan as your controllers management interface?

Re: WLC option 43

Mark Elsen — Wed, 29 Jan 2020 15:28:02 GMT

Yes because the AP still needs the IP adress of the controller.

Re: WLC option 43

Haydn Andrews — Wed, 29 Jan 2020 21:03:56 GMT

An AP has a number of different methods to discover the WLC:

DHCP Option 43
DNS entry for cisco-capwap-controller
Management IP addresses of controllers the LAP remembers previously
A Layer 3 broadcast on the subnet
Statically configured information
Controllers present in the mobility group of the WLC the AP last joined

https://www.cisco.com/c/en/us/support/docs/wireless/5500-series-wireless-controllers/119286-lap-notjoin-wlc-tshoot.html#backinfo

So if the AP and WLC are on the same layer 3 subnet then the AP can use the broadcast method to discover the WLC.

I would only recommend this method when doing lab testing. In production environments even when the WLC is on the same subnet it is best to use the DHCP option 43 or DNS methods

Re: WLC option 43

Leo Laohoo — Wed, 29 Jan 2020 21:20:07 GMT

If the APs and the WLC are in the same VLAN, DHCP Option 43 is not necessary.