To configure advanced settings
Navigate to DEVICE | High Availability > Settings.
Set the Probe Interval to the interval, in seconds, between probes sent to specified IP addresses to monitor that the network critical path is still reachable. This interval is used in logical monitoring for the local HA pair. The default is 20 seconds, and the allowed range is 5 to 255 seconds.
You can set the Probe IP Address(es) on DEVICE | High Availability > Advanced. See Monitoring High Availability.
Set the Election Delay Time to the number of seconds the Active Security Appliance waits to consider an interface up and stable. The default is 3 seconds, the minimum is 3 seconds, and the maximum is 255 seconds.
This timer is useful with switch ports that have a spanning-tree delay set.
Set the Dynamic Route Hold-Down Time to the number of seconds the newly-active Security Appliance keeps the dynamic routes it had previously learned in its route table. The default value is 45 seconds, the minimum is 0 seconds, and the maximum is 1200 seconds (20 minutes).
The Dynamic Route Hold-Down Time setting is displayed only when the Advanced Routing Mode option is selected on NETWORK | System > Dynamic Routing > Settings.
In large or complex networks, a larger value may improve network stability during a failover.
This setting is used when a failover occurs on a High Availability pair that is using either a dynamic routing protocol. During this time, the newly-active appliance relearns the dynamic routes in the network. When the Dynamic Route Hold-Down Time duration expires, SonicOS deletes the old routes and implements the new routes it has learned from routing protocols.
(Optional) To force synchronize the SonicOS preference settings between your primary and secondary HA firewalls, click Synchronize Settings.
This will cause a restart of the standby device.