Paessler PRTG is monitoring software that keeps watch over networks, servers and applications from a Windows machine, with no Linux skills required. It comes from Paessler GmbH, a Nuremberg company founded by Dirk Paessler that traded as Paessler AG until September 2024. According to Wikipedia, the acronym originally stood for Paessler Router Traffic Grapher, and the first release came out in 2003.
In May 2024 Paessler announced a strategic investment from Turn/River Capital, the US firm that went on to buy SolarWinds a year later. The product line now has three main branches: PRTG Network Monitor, installed on the customer’s own servers, PRTG Hosted Monitor, run in the cloud by Paessler, and PRTG Enterprise Monitor for very large estates.
What Paessler PRTG is for
Everything revolves around sensors. A sensor is one specific measurement on one device, such as traffic on a switch port, CPU load on a server, the response time of a web page or the state of a Windows service. Paessler reckons on about ten sensors per device on average, and that total is what the license is based on. PRTG queries devices over SNMP, WMI, SSH, HTTP or plain ping, stores the readings and raises an alarm when a threshold is crossed.
The architecture separates the core server, which stores data and serves the web interface, from probes that do the actual polling. Remote probes can be placed in branch offices or segmented networks. Since PRTG 21.4.73 a multi-platform probe has also been able to collect from Linux machines, Raspberry Pi boards or NAS units, via a NATS server bundled with PRTG since version 26.1.118. The documentation concedes that this probe remains less capable than the Windows one.
Users work in a browser, in the PRTG Desktop application or on a phone. Stable releases arrive a few weeks apart. Version 26.3.122, released in July 2026, added seven sensors, and 26.3.124 in September carried on rebuilding the web interface, parts of which remain in early access.
The comparison with LibreNMS, also in our library, clarifies the positioning. Both read SNMP counters from devices and turn them into graphs, but LibreNMS is GPL-licensed free software that runs on a Linux server with PHP and MariaDB. PRTG installs in a few clicks on Windows, handles Microsoft servers and virtual machines natively and sells that convenience as a subscription. For analysing what flows actually carry, ntopng suits better than either.
Who is it for?
PRTG suits IT departments in small and mid-sized businesses, schools, local authorities or hospitals that look after a mix of Windows servers, switches and printers, with no dedicated Linux team. The free edition, capped at 100 sensors or roughly ten devices by Paessler’s estimate, is enough for a small office, a home lab or a proof of concept.
The main drawbacks stem from the licensing model. Because every measurement consumes a sensor, costs rise quickly once you track each port and each service in detail. The core server needs Windows with its full graphical interface, since Server Core is not supported. Beyond 10,000 sensors the documentation advises adding more core servers. PRTG does not back up network device configurations either, which is the territory of tools such as SolarWinds NCM or Oxidized.
Download Paessler PRTG safely
The Windows installer is available from the trial page on paessler.com, with no credit card needed. After 30 days without a sensor limit, the installation automatically switches to the free 100-sensor edition, which the manual allows for personal and commercial use alike, provided a trial key was obtained. Beyond that, PRTG Network Monitor is sold only as an annual subscription. The public price list starts at 200 dollars a month for 500 sensors and reaches 1,642 dollars a month for 10,000 sensors.
PRTG Hosted Monitor runs on Paessler’s AWS infrastructure, with a choice of 26 regions, and can be trialled for ten days, with no free tier afterwards. It starts at 2,399 dollars a year excluding VAT for 500 sensors. PRTG Enterprise Monitor, designed for more than 10,000 sensors, is listed from 1,671 dollars a month. Paessler’s Android and iPhone apps are free on Google Play and the App Store. A cracked build or a license key sold outside the Paessler portal would hand the credentials for your whole estate to a possibly altered program, when the free edition already covers small needs.
Frequently asked questions
Is PRTG free?
Partly. The freeware edition of PRTG Network Monitor handles up to 100 sensors with no time limit and supports every sensor type. Anything larger needs a paid subscription, and the hosted version has no free equivalent.
Does PRTG run on Linux?
The core server installs only on Windows 10, Windows 11 or Windows Server 2016 to 2025. A multi-platform probe can run on Linux to collect data, and PRTG Hosted Monitor removes the need to run a server at all.
Should I pick PRTG or LibreNMS?
LibreNMS is free without restriction but means administering a Linux server. PRTG is quicker to deploy on Windows and covers Microsoft environments well, but becomes paid beyond 100 sensors. The choice mostly depends on your team’s skills and how many measurements you need to track.
