This article applies as of PRTG 24

PRTG licensing is measured by so-called sensors. To purchase the license that fits my needs, I would like to know: What is a sensor? How many sensors do I need for my infrastructure?

What is a sensor in PRTG?

Short answer

In PRTG, sensors are the basic monitoring elements. One sensor usually monitors one measured value in your infrastructure, for example, the traffic of a switch port, the CPU load of a server, or the free space of a disk drive.

On average, you need about 5-10 sensors per server or one sensor per switch port.

All licenses of PRTG only differ by the maximum number of sensors that you can use for monitoring. For more information, see also the PRTG price list for details.

Note: When you buy one license now, you can upgrade to a larger one at any time.

More detailed answer

In PRTG, you create devices that represent the actual devices, servers, databases, and more in your network. Then you add sensors to these devices.

About devices and sensors

• For example, you can create a device that represents your firewall, a device that represents your Exchange server, and a device that represents your printer.
• To each device, you can add one or more sensors.
• Each sensor monitors one single aspect of a device. This can be, for example, the Ping time, the CPU load on a server, the traffic of a network interface, or the status of the toner cartridge.

Examples of sensors

For example, when monitoring a firewall, an Exchange server, and a printer, you can use the following sensors:

* This is meant as an example only. It depends on your device and your network configuration which sensors you can actually use.

How many sensors do I need?

The number of sensors that is necessary for your individual setup depends on how closely you want to monitor your network. It is your decision whether you set up general Ping and Port monitoring for a device, or whether you monitor it very closely, including many different performance parameters.

Note: As a rule of thumb, you can calculate with about 5 to 10 sensors per device.

What types of sensors are available?

There are more than 250 different sensor types available in PRTG. For a complete list, see the PRTG Manual: Available Sensor Types.