PRTG Manual: Dependencies
You can use dependencies to pause sensors based on the status of a different (master) sensor to avoid false alarms and incorrect downtime recording. A dependency stops the monitoring of one sensor or a set of sensors as soon as the parent sensor shows the Down status or if the parent sensor shows the Paused status because of another dependency. This means, for example, that you can stop monitoring remote network services when the corresponding firewall is down because of connection problems.
When you use the auto-discovery feature, PRTG sets the Ping sensor of a device as the master object for the device by default. This means that monitoring for the entire device is paused if the Ping sensor shows the Down status or if it shows the Paused status because of a dependency. Usually, it makes little sense to monitor any other parameters while the Ping sensor indicates that the device is unavailable.
You do not trigger a status change by dependency if you manually pause a master object or if you pause it by schedule. For more details, see the Knowledge Base: Why will dependent objects not automatically pause when I pause the master object?
If a sensor shows the Paused status because of a dependency, the objects that use the sensor as parent also show the Paused status.
To view the list of dependencies, select Devices | Dependencies and the corresponding dependencies path from the main menu bar. From there you can also access the dependencies graph that visualizes all dependencies in your network.
For more information about the dependency settings, see the settings of the object for which you want to set a dependency, section Schedules, Dependencies, and Maintenance Window.
Why will dependent objects not automatically pause when I pause the master object?