@salvi wrote:
the controller has vlan 919 with ip 192.168.102.1/23. The dhcp server has the scope of 192.168.102.1-103.254 excluding addresses 1-10.
Okay.
For that to work the controller has to have a physical connection to the same LAN as the DHCP server, and then assign users do that VLAN. No helper address is necessary. Let's suppose you connected your LAN to gigabitethernet 0/3 on the controller, you would do this:
config t
vlan 919
interface gigabitethernet 0/3
switchport access vlan 919
You would connect a cable from gigabitethernet 0/3 on the controller to that physical LAN.
You would then go into the Virtual AP of that wireless network and make sure the VLAN is 919. No helper address needed since you can make a physical connection from the controller to an already existing subnet.