Infrastructure monitoring life hacks with PRTG Network Monitor from Paessler AG

Infrastructure monitoring life hacks with PRTG Network Monitor from Paessler AG

Toner level control

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

Some printers do not support the object identifiers (OIDs) built into the PRTG printer’s sensor, so you receive SNMP error #222 when you try to request data. In such cases, the BUILT-in SNMP sensor (customizable table) in PRTG will help to solve the problem. In English-language installations, it is designated as SNMP Custom Table Sensor. To do this, you will need the SNMP table OID. To display the level of filling, the OID “” is used. Enter it in the first step of configuration.

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

Using the SNMP table, the PRTG program in the Then view change the column for identification to the OID “”. It reflects the color of the cartridge. Now specify a channel name. It is displayed next to the sensor result, for example, “filling level”. Next, you need to match the touch channel column. To do this, enter the OID “”, which reflects the current level of filling in percentage. To configure the units of this channel, select the “percentage” item in the drop-down list.

Next, PRTG reads all the sensors of your printer and shows you a table with the available values. Check all the channels you want to add and finish the setup by clicking “Save”. PRTG now configures the sensor for each selected record and sets the name of the sensor based on the information being read. From this point on, the level of filling of the cartridge with toner is displayed, and changes are recorded continuously. For detailed step-by-step instructions with illustrations, see PRTG Database.

Overview of inventory in PRTG

When using PRTG Network Monitor, the structure of the device tree has become increasingly complex over the years. Therefore, it makes sense to check all interval dependencies and active inheritances between hosts from time to time. In addition, you need to list all the sensors and channels in which restrictions have been introduced. By knowing how to do this, you will be able to quickly create relevant reviews.

Sprawling monitoring systems require inventory from time to time.

The required information can be easily read from the PRTG. To do this, we recommend using the PrtgAPI tool, a C#/PowerShell interface individually adapted to PRTG Network Monitor. The Application Programming Interface (API) allows you to read almost any sensor information from the PRTG and then process it in a spreadsheet. To get all the characteristics of the channel, including the sensor ID, 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 sensor dependency report, 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 more information about PrtgAPI, see Paessler Database.

Checking the connection to the MQTT sensor

Many medium-sized manufacturing enterprises are gradually incorporating their machines into the network. They connect in a specially designated area and send the information to the central broker MQTT, where the subsequent processing of the data takes place. It is important for the enterprise to monitor whether the MQTT broker is fully available. There are separate recommendations in this regard.

The MQTT relay sensor checks whether it is possible to connect to the broker.

PRTG Network Monitor offers a special repeater sensor MQTT. It checks if it is possible to connect to the broker and whether the broker accepts messages through Publish. In addition, the sensor monitors whether the broker transmits a message to the relevant participant and, on the one hand, measures the time of the individual connection, and on the other hand, the total time it takes for the signal to pass back and forth from the moment the message is issued to the re-reception.

Setting up the MQTT sensor is very simple and involves only a few steps. The MQTT Round Trip BETA sensor is added to the PRTG. In the sensor settings, a name is assigned to the sensor and the MQTT Topic is stored. The default value is PRTG/roundtrip/%sensorid, where PRTG takes the place of %sensorid with the corresponding sensor ID. To enable the sensor to access the MQTT partition, save your MQTT credentials in the parent device settings. After the sensor is started, it displays the time of the message back and forth, the status of the passage, the connection time of the publisher and the time of connection of the subscriber in different channels of the sensor.

Remote access to the primary PRTG server

PRTG Network Monitor is used in many companies to monitor IT infrastructure. The question often arises as to how to access the primary PRTG server outside the corporate network. What the administrator should consider 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 well, 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 apps. However, before this becomes possible, you need to be sure that you will be able to 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 inability of another person to log into your PRTG account. To do this, you must change the password for the default 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 externally through insecure HTTP. Therefore, you should ensure that PRTG 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” under “Settings / System Management / Web Interface, Web Server section”. To access the primary server installation from the outside, you must open or redirect the required ports in the firewall. To do this, create NAT rules for these ports. Setting NAT rules in a firewall can vary greatly depending on the manufacturer you are using. Therefore, check 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 might look like the illustration. The rule for HTTP is optional, but greatly simplifies the process. If you type “prtgserver. <mydomain.tld>”, you will first attempt to access the website via HTTP. If you do not want to create a NAT rule for HTTP, you will need to enter prtgserver each time. <mydomain.tld>.

This is what NAT rules might look like on the firewall to grant remote access to the PRTG.

You should also make sure that Windows Firewall is disabled on the PRTG server, or that you have created the appropriate rules. You can now remotely monitor PRTG installations via PRTG mobile apps or access PRTG’s web interface over the internet from other clients. For more information about configuring access to PRTG Network Monitor through a firewall, including useful advanced settings, see How-to.