Segment a Network using a FG-80E Firewall

Modifyinc · October 12, 2020

We now own a building that is setup using an ONT, Fortigate Firewall model FG-80E, and two HPE OfficeConnect 1920S series model JL385A switches. Switch 1 is 192.168.1.11 and Switch 2 is 192.168.1.12. These components are located in the first building, Building A. Building A's network provides internet to Switch 3 (192.168.1.14) in Building B via Switch 2 using the SFP fiber uplink ports.

Since we now own both buildings and pay the ISP, we want to reconfigure the Fortigate so we can segment or separate the two buildings into two different networks. We have no idea what the credentials are for the Fortigate so it'll likely require a hard reset. I've never configured a hardware firewall in this way, other than maybe an EdgeRouter X. Any suggestions for tutorials or guides that show you how to segment a network into two networks using the FG-80E firewall? I didn't find much for this model, but what about other models that likely have the same setup or use the same Fortigate OS or menu structure?

Does the network need to be already segmented into two subnets or can the firewall do this? I'm confused whether the firewall can only direct the packets for the already segmented network or can it actually segment and direct packets. I know on the EdgeRouter X, I could create an IP with a different subnet for each port, I assume the firewall can do this.