- On the primary FortiGate, go to System > Settings and change the Host name to identify this as the primary FortiGate in the HA cluster.
- Go to System > HA and set the Mode.
Set the Mode to Active-Passive.
Set the Device priority to a higher value than the default (in this example, 250) to ensure this FortiGate is always the primary FortiGate.
Set a Group name and Password.
Check that the Heartbeat interfaces (in this example, port3 and port4) are selected and the Heartbeat Interface Priority for each is set to 50.
Since the backup FortiGate isn't available yet, when you save the HA configuration, the primary FortiGate operates normally as a cluster of one.
If these steps don't start HA mode, make sure that none of the FortiGate interfaces use DHCP or PPPoE addressing.
If there are other FortiOS HA clusters on your network, you might need to change the cluster group ID using this CLI command:
config system ha
set group-id 25