- Go to System > High Availability > Configuration.
- Under HA Configuration, set Mode of operation to config master if the FortiMail unit is the primary unit in the active-passive group. Select config slave if the FortiMail unit is the secondary unit.
- Enter a Shared password. This password must be the same for both the primary and secondary units.
- Under Advanced options, set an HA base port value (20000 by default). This will be used for the heartbeat signal, and synchronization control, including data and configuration synchronization.
- Click Create and double-click the entry created. For the master unit, enter the slave unit's IP address. If you are configuring the slave unit, enter the master unit's IP address.
- Click Apply.