PRTG Manual: Architecture and User Interfaces

In this section, you can find an overview of the components of PRTG and how it works.


You can classify the components of PRTG into three main categories: system parts, user interfaces, and basic system administration tools.



System Parts

PRTG core server
This is the central part of a PRTG installation. The PRTG core server includes the data storage, the web server, the report engine, the notification system, and more. The PRTG core server is configured as a Windows service that permanently runs.

This is the part of PRTG that performs the actual monitoring. There are local probes, remote probes, and cluster probes in PRTG Network Monitor, and there are hosted probes and remote probes in PRTG Hosted Monitor. Probes forward all monitoring data to the central PRTG core server. Probes are configured as Windows services that permanently run.

i_round_redWe assume that all systems on which the PRTG core server with the local probe or any remote probes run are secure. It is every system administrator's responsibility to make sure that only authorized persons can access these systems. For this reason, we highly recommend that you use dedicated machines for your PRTG system parts.

User Interfaces

PRTG web interface
With the Asynchronous JavaScript and XML (AJAX) based PRTG web interface, you can configure devices and sensors, review monitoring results, and configure the system administration and user management.

PRTG Desktop
PRTG Desktop is a cross-platform application that you can use as an alternative interface for fast access to data and monitoring management. With PRTG Desktop, you can connect to several independent PRTG core servers or PRTG Hosted Monitor instances to display their data and centrally manage your monitoring.

PRTG apps for mobile network monitoring
With the PRTG apps for iOS and Android, you can monitor your network on the go and receive push notifications in case of alerts.

System Administration Tools

PRTG Administration Tool on PRTG Core Server Systems i_prtg
With the PRTG Administration Tool on the PRTG core server system, you can configure basic PRTG core server settings in PRTG Network Monitor such as the PRTG System Administrator user login, web server IP addresses and the web server port, probe connection settings, the cluster mode, the system language, and more.

PRTG Administration Tool on Remote Probe Systems
With the PRTG Administration Tool on the remote probe system, you can configure basic remote probe settings such as the name of the remote probe, IP address and server connection settings, and more.

PRTG Core Server

The PRTG core server is the heart of PRTG. It performs the following tasks:

  • Configuration management for target devices (for example, servers, workstations, printers, switches, routers, or virtual machines (VM))
  • Management and configuration of connected probes
  • Cluster management
  • Database for monitoring results
  • Notification management including a mail server for email delivery
  • Report generation and scheduling
  • User account management
  • Data purging (for example, deleting data that is older than 365 days)
  • Web server and application programming interface (API) server

i_round_blueIn a cluster, the master node is responsible for all of these tasks.

The built-in and secure web server, for which you require no additional Microsoft Internet Information Services (IIS) or Apache, supports HTTP as well as HTTPS (secured with Secure Sockets Layer (SSL)/Transport Layer Security (TLS)). It serves the PRTG web interface when you access it via a browser and also answers PRTG API calls.

i_round_blueThe PRTG core server is configured as a Windows service that permanently runs. A logged-in user is not required.


On the probe, PRTG performs the actual monitoring via the sensors that you created on a device (for example, a computer, a router, a server, a firewall, and more). The probe receives its configuration from the PRTG core server, runs the monitoring processes, and delivers monitoring results back to the PRTG core server.

i_prtgFor PRTG Network Monitor, there is always a local probe that runs on the PRTG core server system.

i_podFor PRTG Hosted Monitor instances, there is always a hosted probe that runs on the PRTG core server system that Paessler hosts for you.

PRTG Core Server and Local Probe That Monitors a LAN

PRTG Core Server and Local Probe That Monitors a LAN

The actual monitoring is performed by probe processes that run on one or more systems.

i_round_blueThe probes are configured as a Windows service that permanently runs. A logged-in user is not required.

Probe Type


Local probe i_prtg

During the installation, PRTG automatically creates the local probe. In a single-probe installation, which is the default setup, the local probe performs all monitoring.

For PRTG Network Monitor, the PRTG core server with the local probe inside the corporate LAN can monitor services and servers in the entire LAN.

Hosted probe i_pod

When you create a PRTG Hosted Monitor instance, the system automatically creates the hosted probe. The hosted probe shows monitoring values of the hosted instance and can monitor devices, servers, and services that are publicly available in the internet like websites.

Remote probes

You can create additional remote probes to monitor multiple locations, to monitor a LAN with PRTG Hosted Monitor, or for several other scenarios. Remote probes use SSL/TLS-secured connections to the PRTG core server. With remote probes, you can securely monitor services and systems inside remote networks that are not publicly available or that are secured by firewalls.

i_square_cyanFor more information, see section Add Remote Probe.

i_playFor more information, see the video tutorial: Distributed monitoring with PRTG.

Cluster probes i_prtg

In a cluster, a cluster probe runs on all cluster nodes. All devices that you create on the cluster probe are monitored by all cluster nodes, so data from different perspectives is available and monitoring continues even if one of the cluster nodes fails.

Mini probes i_prtg

Mini probes let you create small probes on any device, not only on Windows systems.

i_square_cyanFor more information, see section Mini Probe API.

System Health Monitoring

PRTG automatically monitors the system health of the PRTG core server and of each probe to discover overload situations that can distort monitoring results. To monitor the status of the probe system, PRTG automatically creates the Core Health and Probe Health sensor, the System Health sensor, the Cluster Health sensor, some disk free and bandwidth sensors for all installed network cards, as well as a Common SaaS sensor that checks the availability of widely used software as a service (SaaS) providers.

We recommend that you keep these sensors. However, you can remove all of them except for the health sensors.

The health sensors measure various internal system parameters of the probe system hardware and the probe's internal processes and compute the results. Investigate frequent values below 100%.



Getting started with PRTG

How to connect PRTG through a firewall in 4 steps



Distributed monitoring with PRTG

What is a sensor?