You can select the interface to use for HA control traffic. The HA link should connect the identical ports of the HA pair, for example, X3 of both appliances.
Before configuring the options on the High Availability > Settings page, prepare your devices for High Availability with the following steps:
Configure both SMA appliances as separate devices with independent IP addresses on your subnet.
SMA appliances in an HA pair cannot be deployed behind a proxy.
Connect the X3 interfaces of the two appliances together with a CAT 5E or better cable to ensure a gigabit connection.
SonicWall Inc. recommends that you backup and download the settings for both SMA appliances at this stage.
In a browser, log into the primary unit and navigate to the Network > Interfaces page. Confirm that the X3 port is active by checking the Status. It should show 1000 Mbps Full Duplex.