What is "ip dhcp request-option-all" configuration

ip dhcp request-option-all configuration decides the interface on which cnPilot AP shall learn 

1. IP default gateway 

2. DHCP client options like Option 43 (Controller discovery like controller host name / IP address)

3. DNS Servers

4. Domain name and etc    

By default configuration is enabled on VLAN 1.  In cnPilot AP, DHCP client can be configured on multiple interfaces like enabling DHCP client on VALN 10, 20 and 30. AP can get IP address on VLAN 10, 20 and 30 along with default router, DNS server addresses and etc from all the interfaces. Since "ip dhcp request-option-all" is enabled on VLAN 1, the information learned  from VLAN 1 will be installed or used by the AP.

If the deployment invloves learning IP Default Gateway, DNS servers, Domain name on other than VLAN 1 say VLAN 10 through DHCP server, we need to configure "ip dhcp request-option-all" on this interface in this case VLAN 10

The cli for the same is 

E410-9CBBF5(config-vlan-10)# ip dhcp request-option-all