Final answer:
Virtual domains must be configured first in a Fortigate fabric.
Step-by-step explanation:
In a Fortigate fabric, the Virtual domains must be configured first. Virtual domains, also known as VDOMs, allow you to divide a single Fortigate device into multiple virtual devices, each with its own set of configuration settings. Once the VDOMs are set up, you can proceed to configure other elements such as Firewall policies and Security profiles to define the behavior of traffic passing through the fabric. The Fabric connector is responsible for connecting different fabric elements together and comes into play after the initial configuration.