<%NUMBERING1%>.<%NUMBERING2%>.<%NUMBERING3%> PRTG Manual: Architecture and User Interfaces

In this section, we give you an overview of what PRTG is and how it works. If you are new to PRTG or want to learn more, read on for an introduction to PRTG and its components.


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



System Parts

PRTG core server
This is the central part of a PRTG installation and includes data storage, web server, report engine, a 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 on premises, and there are hosted probes and remote probes in PRTG hosted by Paessler. All monitoring data is forwarded to the central PRTG core server. Probes are configured as Windows services that permanently run.

i_round_redWe assume that all computers 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 machines. For this reason, we highly recommend that you use dedicated machines for your PRTG system parts.

User Interfaces

PRTG web interface
The Asynchronous JavaScript and XML (AJAX) based PRTG web interface is used for the configuration of devices and sensors, as well as for reviewing monitoring results. Also, system administration and user management are configured here.

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 by Paessler instances to display their data and manage your monitoring centrally.

PRTG apps for mobile network monitoring
Monitor your network on the go with PRTG and apps for iOS and Android.

System Administration Program

PRTG Administration Tool on core server system i_pop
Used to configure basic PRTG core server settings in PRTG on premises, such as PRTG System Administrator user login, web server IPs and port, probe connection settings, cluster mode, system language, and more.

PRTG Administration Tool on remote probe system
Used to configure basic settings such as name of the remote probe, IP and server connection settings, and more.

PRTG Core Server

The PRTG core server is the heart of PRTG and it performs the following tasks:

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

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

The built-in, fast, and secure web server (no additional Microsoft Internet Information Services (IIS) or Apache is required) 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 (for example, for user scripts).

i_round_bluePRTG core server and probes are configured as Windows services that are permanently run by the Windows system without the requirement for a logged-in user.


On the probe, PRTG performs the actual monitoring via the sensors created on a device (for example, computer, router, server, or firewall). 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_popFor PRTG on premises, there is always the local probe that runs on the same machine as the PRTG core server.

i_podFor PRTG hosted by Paessler instances, there is always the hosted probe that runs on the PRTG core server system that we host for you.

PRTG Core Server and Local Probe Monitoring a LAN

PRTG Core Server and Local Probe Monitoring a LAN

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

i_round_bluePRTG core servers and probes are configured as Windows services that are permanently run by the Windows system without the requirement for a logged-in user.

Probe Type


Local probe in PRTG on premises

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

For PRTG on premises, the PRTG core server with the local probe inside the corporate LAN can monitor services and servers in the entire LAN. For PRTG hosted by Paessler, you need at least one remote probe installation in your network for this purpose.

Hosted probe in PRTG hosted by Paessler

When you create a PRTG hosted by Paessler 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, for example, websites. To monitor your LAN, you need at least one remote probe installation in your network.

The local probe is not available in PRTG hosted by Paessler.

Remote probes

You can create additional remote probes to monitor multiple locations, for LAN monitoring with PRTG hosted by Paessler, or for several other scenarios. They use SSL/TLS-secured connections to the PRTG core server and with them, you can securely monitor services and systems inside remote networks that are not openly available or 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 in PRTG on premises

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 in PRTG on premises

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 may distort monitoring results. To monitor the status of the probe system, PRTG automatically creates a few sensors. These include the Core Health and Probe Health, System Health, Cluster Health, 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, but you can optionally remove all of them except for the Health sensors. They measure various internal system parameters of the probe system hardware and the probe's internal processes and they compute the results. You should investigate frequent or repeated values below 100%. Check the channels of a particular sensor for details.



Getting started with PRTG

How to connect PRTG through a firewall in 4 steps



PRTG basics

Distributed monitoring with PRTG

What is a sensor?

Understanding Basic Concepts