SonicWALL 5.8.1 Manuale Utente

SonicWALL High Availability cannot be configured using the built-in wireless interface, nor 
can it be configured using Dynamic WAN interfaces.

The selected interface must be the same one that you physically connected as described in 

.

To configure the High Availability Pair so that the Primary unit takes back the Primary role once 
it restarts after a failure, select Enable Preempt Mode. Preempt mode is recommended to be 
disabled when enabling Stateful High Availability, because preempt mode can be over-
aggressive about failing over to the Backup appliance.

To back up the settings when you upgrade the firmware version, select Generate/Overwrite 
Backup Firmware and Settings When Upgrading Firmware.

Select the Enable Virtual MAC checkbox. Virtual MAC allows the Primary and Backup 
appliances to share a single MAC address. This greatly simplifies the process of updating 
network ARP tables and caches when a failover occurs. Only the switch to which the two 
appliances are connected needs to be notified. All outside devices will continue to route to the 
single shared MAC address.

Optionally adjust the Heartbeat Interval to control how often the two units communicate. The 
default is 5000 milliseconds; the minimum supported value is 1000 milliseconds. You can use 
higher values if your SonicWALL handles a lot of network traffic. 

Set the Failover Trigger Level to the number of heartbeats that can be missed before failing 
over. The default is 5.

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 is used in logical 
monitoring. SonicWALL recommends that you set the interval for at least 5 seconds. The 
default is 20 seconds, and the allowed range is 5 to 255 seconds. You can set the Probe IP 
Address(es) on the High Availability > Monitoring screen. See 

.

Set the Probe Count to the number of consecutive probes before SonicOS Enhanced 
concludes that the network critical path is unavailable or the probe target is unreachable. This 
is used in logical monitoring. The default is 3, and the allowed range is 3 to 10.

Set the Election Delay Time to the number of seconds allowed for internal processing between 
the two units in the High Availability Pair before one of them takes the Primary role. The default 
is 3 seconds. 

Set the Dynamic Route Hold-Down Time to the number of seconds the newly-Active 
appliance keeps the dynamic routes it had previously learned in its route table. This setting is 
used when a failover occurs on a High Availability pair that is using either RIP or OSPF dynamic 
routing. When a failover occurs, Dynamic Route Hold-Down Time is the number of seconds