Lifehacks infrastructure monitoring using PRTG Network Monitor from Paessler AG

Toner Level Control

Many administrators would find it very practical to control the toner level in the cartridges of all printers using the PRTG Network Monitor. But not all devices support object identifiers (OIDs) using the SNMP sensor. However, there is an option to monitor the level of toner using PRTG.

Some printers do not support the object identifiers (OIDs) built into the PRTG printer sensor, therefore, when trying to request data, an SNMP error message No. 222 appears. In such cases, the SNMP sensor (custom table) built into the PRTG will help solve the problem. In English installations, it is designated as SNMP Custom Table Sensor. To do this, you need the OIDs of the SNMP table. To display the filling level, the OID “″ is used. Enter it in the first step of the setup.

Using the SNMP table, PRTG displays the current toner levels as a list.

Then change the column for identification to OID “”. It reflects the color of the cartridge. Now set the channel name. It is displayed next to the sensor result, for example, “filling level”. Then you need to match the column of the sensory channel. For this, the OID “″ is introduced, which reflects the current level of filling in percent. To configure the units of this channel, select the “percentage” item in the drop-down list.

Next, the PRTG reads all the sensors on your printer and shows you a table with the available values. Check all the channels you want to add and complete the setup by clicking Save. Now the PRTG adjusts the sensor for each highlighted record and sets the name of the sensor based on the read information. From this moment, the toner level of the cartridge is displayed, and changes are recorded continuously. For detailed step-by-step instructions with illustrations, see PRTG Knowledge Base.

PRTG inventory overview

With PRTG Network Monitor, the structure of the device tree has become more complex over the years. Therefore, it makes sense from time to time to check all interval dependencies and active inheritance between hosts. In addition, you need to list all the sensors and channels in which restrictions have been introduced. Knowing how to do this, you can quickly create relevant reviews.

Overgrown monitoring systems from time to time require an inventory.

The required information can be read without problems from the PRTG. To do this, we recommend using the PrtgAPI tool – the C # / PowerShell interface, individually adapted to the PRTG Network Monitor. The application program interface (API) allows you to read almost any information about the sensor from PRTG, and then process it in a spreadsheet. To get all the characteristics of the channel, including the sensor identifier, the following command is executed in the API:
Get-Sensor * cpu * | Get-Channel |
Export-Csv C: channelLimits.csv -NoType

If you want to include the sensor name in the table, you can add it using the Select object. The command line might look like this:
$ sensors = get-sensor * cpu *
$ sensors | foreach {
$ s = $ _ $ s | Get-Channel | select @ {l = “SensorName”; e = {$ s.Name}},
SensorId, Name, Id, * limit *
} | Export-Csv C: channelLimits.csv -NoType

If you want to create a report of sensor dependencies, the Get-ObjectProperty object will help you. It allows you to analyze the DependencyType and DependentObjectId properties of the SensorSettings object. For detailed instructions, including additional information about PrtgAPI, see Paessler Knowledge Base

Checking the connection to the MQTT sensor

Many medium-sized manufacturing enterprises are gradually including their machines in the network. They are connected in a specially defined area and send information to the central MQTT broker, where subsequent data processing takes place. It is important for the company to monitor whether the MQTT broker is fully accessible. There are separate recommendations on this score.

The MQTT Relay Sensor checks if it is possible to connect to a broker.

PRTG Network Monitor offers a special repeater sensor MQTT. It checks whether it is possible to connect to the broker, and whether the broker accepts messages through Publish. In addition, the sensor controls whether the broker transmits the message to the relevant participant, and, on the one hand, measures the time of an individual connection, and on the other hand, the total time required for the signal to go back and forth from the moment the message was issued until it is received again.

Setting up the MQTT is very simple and involves just a few steps. The MQTT Round Trip BETA sensor is added to the PRTG. In the sensor settings, a name is assigned for the sensor and the MQTT (MQTT Topic) section is saved. The default value is PRTG / roundtrip /% sensorid, where PRTG takes the place of% sensorid with the corresponding sensor identifier. To allow the sensor to access the MQTT section, save your MQTT credentials in the settings of the parent device. After starting the sensor, it displays the time the message went back and forth, the state of the passage, the connection time of the publisher and the connection time of the subscriber in different channels of the sensor.

Remote access to the main PRTG server

PRTG Network Monitor is used by many companies to monitor IT infrastructure. Often the question arises of how to access the main PRTG server outside the corporate network. What the administrator must take into account in this case, and what precautions are important to prevent unauthorized access by third parties, is presented in the following recommendation.

You have configured PRTG on your internal network with your personal IP address, for example, Everything works fine, but now you also want to access the main PRTG server over the Internet from another computer. To do this, you can use the PRTG mobile applications. However, before this becomes possible, you need to be sure that you can access the main PRTG server from the outside, including through the firewall.

Since security is alpha and omega, you first need to take care of the impossibility of another person entering your PRTG account. To do this, change the default password for the administrator account if you have not already done so. To check if you are using the default password, simply go to “Settings / Account Settings / My Account, User Account section” in the PRTG web interface.

In addition, you should not access the PRTG instance from outside through insecure HTTP. Therefore, make sure that the PRTG program is configured to use HTTPS for all connections to the PRTG web interface. To do this, select “Secure HTTPS Server as the Transmission Control Protocol (TCP) port for incoming web server requests” in the “Settings / System Management / Web Interface, Web Server” section. To access the installation of the main server from the outside, you must open the necessary ports in the firewall or redirect them. To do this, create NAT rules for these ports. Setting NAT rules in the firewall can vary greatly depending on the manufacturer. Therefore, read the documentation for your device or model.

In our example, if the PRTG program is running on a server with an IP address of, the NAT rules may look as shown in the illustration. The rule for HTTP is optional, but greatly simplifies the process. If you type “prtgserver.”, An attempt will first be made to access the website via HTTP. If you do not want to create a NAT rule for HTTP, instead you need to enter it every time prtgserver..

This may look like NAT rules on the firewall to provide remote access to PRTG.

You should also make sure that Windows Firewall is disabled on the PRTG server, or that you have created the appropriate rules. Now you can remotely monitor the installation of PRTG via PRTG mobile applications or access the PRTG web interface via the Internet from other clients. For more information about setting up access to the PRTG Network Monitor through the firewall, including useful advanced settings, see How-to

You can learn about the capabilities of Paessler PRTG, download the trial version, ask a question to a Softline specialist (Paessler’s key partner in Russia and the CIS) on the website

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