Security & SD-WAN is a menu you only get if you deploy an MX appliance in the Network in question.   With just MR, there are generally two alternative approaches, though you can mix-and-match between different SSIDs.  You could use NAT mode, where each AP is it's own DHCP server and (as the name implies) performs NAT.   This is generally used for static Guest users.   Most corporate SSIDs will run in Bridged mode, where you will need to provide a DHCP server elsewhere, either directly in the VLAN in which clients are placed or as a DHCP helper on the gateway for said VLAN.   In an environment where an MX is deployed, it's the MX that generally provides the default gateway function and is setup to locally act as a DHCP server or relay - maybe to a DC with a fully centralised DHCP setup, over meraki secure SD-WAN.  Have a good read of this:   https://documentation.meraki.com/MR/Client_Addressing_and_Bridging/SSID_Modes_for_Client_IP_Assignment   ... View more