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

In this section, we give you an overview of what PRTG Network Monitor 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 Network Monitor into three main categories: system parts, control interfaces, and a basic administration interface.


Part of PRTG

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.

icon-i-round-redWe assume that all computers on which the PRTG core server with its local probe or any remote probes run are secure. It is every 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 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
A cross-platform application as an alternative to the web interface to manage your monitoring. With PRTG Desktop, you can connect to different independent PRTG core server installations or PRTG hosted by Paessler instances and review their data at a glance.

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 icon-prtg-on-premises
Used to configure basic PRTG core server settings in PRTG on premises, such as administrator 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 probe settings such as name of the probe, IP and server connection settings, and more.

PRTG Core Server

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

  • Configuration management for monitoring objects (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 PRTG on premises cluster, the current 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 secure HTTPS (via Secure Sockets Layer (SSL)). It serves the web interface when you access it via a browser and also answers PRTG API calls (for example, for user scripts or PRTG Desktop).

icon-i-roundPRTG 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.

icon-prtg-on-premisesOn every system running a PRTG on premises core server, there is always a local probe that runs on the same machine.

icon-prtg-on-demandIn PRTG hosted by Paessler instances, there is always a hosted probe that runs on the PRTG core server system that we host for you.

PRTG Core Server and Local Probe Monitoring a Local Area Network

PRTG Core Server and Local Probe Monitoring a Local Area Network

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

icon-i-roundPRTG 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—that is the default setup—the local probe performs all monitoring.

The PRTG on premises core server with the local probe inside the corporate LAN can monitor services and servers in the entire LAN. In 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 creating a PRTG hosted by Paessler instance, the system automatically creates the hosted probe. The hosted probe shows monitoring values of the hosted PRTG 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 achieve monitoring of multiple locations, for LAN monitoring with PRTG hosted by Paessler, or for several other scenarios. They use Transport Layer Security (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.

icon-book-arrowsFor more information, see section Remote Probes and Multiple Probes.

icon-playFor more information, see the video tutorial: Distributed Monitoring with PRTG

Cluster Probes in PRTG on premises

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

Mini Probes in PRTG on premises

PRTG Mini Probes let you create small probes on any device (not just on Windows systems). You can implement mini probes to gather monitoring data exactly like you need it and you can create them on any platform.

icon-book-arrowsFor more information, see section Mini Probe API.

System Health Monitoring

PRTG automatically monitors the system health of its own PRTG core server and of each probe to discover overloading situations that may distort monitoring results. To monitor the system status of the probe computer, 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 compute resulting values. Frequent or repeated values below 100% should be investigated. Check the channels of a particular sensor for details.


Paessler Website: PRTG e-learning in 9 modules

Paessler Website: How to connect PRTG through a firewall in 4 steps

Video Tutorials: PRTG Basics

Video Tutorial: Distributed Monitoring with PRTG

Video Tutorial: What Is a Sensor?


Understanding Basic Concepts—Topics

Keywords: Architecture,Architecture Basic Concept