SonicWALL 3500 User Manual

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  Configuring a State Sync Pair in NAT/Route Mode  
Adjusting High Availability Settings
On the High Availability Settings page, there are four user-
configurable timers that can be adjusted to suit your network’s 
needs:
Heartbeat Interval (seconds) – This timer is the length of 
time between status checks. By default this timer is set to 5 
seconds; using a longer interval will result in the 
SonicWALL taking more time to detect when/if failures 
have occurred.
Failover Trigger Level (missed heartbeats) – This timer 
is the number of heartbeats the SonicWALL will miss 
before failing over. By default, this time is set to 5 missed 
heartbeats.This timer is linked to the Heartbeat Interval 
timer – for example, if you set the Heartbeat Interval to 10 
seconds, and the Failover Trigger Level timer to 5, it will be 
50 seconds before the SonicWALL fails over.
Probe Interval – This timer controls the path monitoring 
speed. Path monitoring sends pings to specified IP 
addresses to monitor that the network critical path is still 
reachable. The default is 20 seconds, and the allowed 
range is from 5 to 255 seconds.
Election Delay Time – This timer can be used to specify 
an amount of time the SonicWALL will wait to consider an 
interface up and stable, and is useful when dealing with 
switch ports that have a spanning-tree delay set.
Synchronizing Firmware
Checking the Synchronize Firmware Upload and Reboot 
checkbox allows the Primary and Backup SonicWALL security 
appliances in HA mode to have firmware uploaded on both 
devices at once, in staggered sequence to ensure security is 
always maintained. During the firmware upload and reboot, you 
are notified via a message dialog box that the firmware is 
loaded on the Backup SonicWALL security appliance, and then 
the Primary SonicWALL security appliance. You initiate this 
process by clicking on the Synchronize Firmware button.