The dashboard shows the aggregated data for all firewalls onboarded to your
tenant and are also sending telemetry data.
The Device health dashboard shows you the cumulative health status and
performance of your deployment based on the health scores of the onboarded
NGFWs. The device health is determined by the severity of the health score
(0-100) and its corresponding health grade (good, fair, poor, critical). The
health score is calculated based on the priority, quantity, type, and status of
the open alerts.