Before FortiGate can steer traffic according to SD-WAN rules, certain configuration elements must be present. The guide states:

"SD-WAN is not a standalone feature and interacts with several fundamental FortiGate configurations. Specifically, you must: (1) Define the interfaces (physical, VLAN, or IPsec) that will act as SD-WAN members, (2) Create firewall policies to allow traffic to be steered by SD-WAN, and (3) Set up routing so that traffic has valid routes via SD-WAN members. Without these, SD-WAN rules will not be able to match or steer any traffic."

Security profiles and traffic shaping are not mandatory for basic SD-WAN steering but can be layered on for enhanced security and QoS once foundational elements are present.