Object Hierarchy: Probes, Groups, Devices, Sensors, Channels

All objects in PRTG are arranged in a tree-like hierarchy to create an easy to navigate list and to give the user the possibility to arrange them in groups that monitor similar devices, locations or services.

Devices, Sensors, Channels

In PRTG Network Monitor, you can add "Devices" that you want to monitor. These devices can be for example:

  • A web or file server.
  • A router or a network switch.
  • A so called "Probe Device", which is a PRTG-internal system device. This device has access to the computer on which the probe is running on.
  • Almost every device in your network that has its own IP address.

Each device has a number of "Sensors", where the actual monitoring is performed. Each of these sensors monitors one single aspect of a network device. For example:

  • One network service like SMTP, FTP, HTTP, etc.
  • The traffic of one port of a network switch.
  • The CPU or memory load of a device.
  • One network card's traffic.
  • One NetFlow device, etc.

Each sensor has a number of "Channels" through which it receives the different data streams. Channels can contain, for example:

  • Downtime and Total (for a WMI CPU Load sensor).
  • Downtime, Percent Available Memory and Available Memory (for a WMI Memory sensor).
  • Downtime, Average (for a PING sensor).
  • Downtime, Loading time, Bytes received, Download Bandwidth and Time of first Byte (for a HTTP advanced sensor), etc.

Groups and Probes


Each device is part of a "Group". You can arrange your devices in different nested groups to reflect the structure of your network.

Each group is part of a "Probe". This is the platform on which the monitoring takes place. All objects configured below a probe will be monitored via that probe. Every PRTG Core installation automatically installs a local probe service. You can add additional probes and remote probes to your configuration to include remote devices from outside your network into the monitoring (see section Multiple Probes and Remote Probes).

Finally, the "Root" group is the topmost instance in PRTG, which contains all other objects.

The hierarchical order described is also used to define common settings for larger groups of objects, e.g. settings of the root group usually apply to all other objects below it (see section Inheritance of Settings).

Here is a sample configuration with one probe, several groups, devices and their sensors:



You can specify a priority for each object in the sensor tree, shown with 1 star ("*") for the lowest priority to 5 stars ("*****") for the highest priority. By default, PRTG sensors are sorted first by priority and then alphabetically by name in lists like "Alarms" or "Sensors". The default priority is three stars ("***") so you can prioritize objects in your configuration quickly. Simply left click an object and select the desired setting from the context menu:


You can also click on the stars directly in an object's detail view. The basic idea of the priority concept is ensure that the most important sensors are always shown first in the sensors and alarms lists. This guarantees you never miss an important outage.

Favorite Sensors

Another method to highlight important sensors is to mark them as "Favorite Sensors", also accessible through a sensor's context menu. A list of the favorite sensors can be found on the Dashboard 1 page ("Home | Dashboard 1") and in the Sensors menu ("Sensors | Favorite Sensors").


Keywords: Probe,group,device,Sensors,Channels