All-in-One Port
Monitoring Software

✔ PRTG monitors open and closed ports

✔ PRTG monitors bandwidth

✔ PRTG monitors traffic

✔ PRTG monitors connections using UDP and TCP protocols

✔ PRTG includes SNMP, NetFlow, and packet sniffing


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100 sensors, perfect for smaller networks

Port Protocols: Definition, Traffic, Security


A port is a part of the network address and ensures the proper distribution of connections and data packets. Valid port numbers range from 0 to 65535. Many applications use typical or standardized ports (“well-known ports”), which are usually registered with the IANA. These include FTP (port 20), SMTP (port 25), and SNMP (port 161). These ports are used primarily by protocols such as the Transmission Control Protocol (TCP) and User Datagram Protocol (UDP).

Traffic Monitoring

Many administrators search for port monitoring software to monitor the traffic that runs through their routers and switches, and the amount of bandwidth that is consumed. What they really need is network monitoring software. PRTG comes with a number of advantages: all-in-one monitoring software, it uses port sniffing with SNMP as a means of monitoring bandwidth.


Open ports put your network at risk. They are used, for example, to introduce Trojans. While it is true that many administrators are highly security-oriented, it takes a superhuman effort to constantly check which ports are open and which are closed. Often ports are opened temporarily for individual applications and then forgotten. In such cases, PRTG uses the TCP protocol and keeps administrators up-to-date by way of a built-in, customizable alarm system.

A quick introduction to PRTG: Port monitor

Decision time: Individual port monitoring software or an all-in-one solution? 

Isolated applications: While searching for port monitoring software, you are bound to stumble across a number of isolated software applications such as CurrPorts or Port Scan. In the short term, such solutions are perhaps not all that bad. However, they tend to make monitoring complex and confusing. Those opting for several isolated applications have to live with higher maintenance costs and often limited features. It is extremely difficult, therefore, to keep a constant eye on your network.

Advantages of PRTG: With PRTG, you get one central monitoring tool for your entire network. The first 100 PRTG sensors are free and never expire. Enjoy the full version of our network monitoring tool for 30 days for free, including all its sensors and functions. You will thus gain a complimentary and risk-free glimpse into our software, and can even set up port monitoring and collect some initial data. Upgrade whenever you like.

Port Monitoring: 
5 reasons why PRTG is the right tool for you

All in one

Whether SNMP, packet sniffing, or NetFlow: All standard monitoring protocols are included. The notification system is also part of the overall package. Get started with a central monitoring tool that works on your entire network – and finally enjoy some peace of mind as you concentrate on your other tasks. Many administrators use PRTG because they wish to do away with their “hodgepodge” of monitoring tools.


For nearly 20 years, Paessler AG has been fully dedicated to the development of its PRTG monitoring software in order to offer the perfect network monitoring tool. Today, more than 150,000 administrators worldwide put their trust in our monitoring software for the monitoring of their networks and traffic.


PRTG comes with extensive support. We aim to resolve every support inquiry within 24 hours (on business days). Our knowledge base contains a number of concrete application tips. You will find answers to many of your questions there. Our manual also contains instructions for every sensor.


PRTG lets you create your own customized reports. Thanks to these reports, you can study the evolution of bandwidth, system load, and many other parameters over the course of months or years. This will help you with the long-term planning of your network infrastructure. You can also detect load peaks and react to them quickly.


PRTG comes with a built-in notification system. This alarm is entirely customizable. You will only receive a notification if an error occurs. At the same time, the alarm can be configured in such a way as to provide prompt alerts – before larger problems or system failures arise.

The right sensors for monitoring your ports and traffic


  • SNMP Traffic Sensor: The SNMP Traffic Sensor monitors data traffic on your routers and switches. Find out more about the SNMP Traffic Sensor
  • Packet Sniffer Sensor: The Packet Sniffer Sensor monitors data packets according to types of traffic (mail, FTP, Citrix, chat, etc.). Find out more about the Packet Sniffer Sensor.
  • NetFlow v9 Sensor: With the NetFlow V9 Sensor, you can monitor your Cisco hardware using NetFlow technology. Also available in V5 or IPFIX. Find out more about the NetFlow V9 Sensor


  • Port Sensor: The Port Sensor monitors a network application by connecting to the respective port via TCP. It can also perform Telnet commands. Find out more about the Port Sensor.
  • Port Range Sensor: The Port Range Sensor monitors a range of ports and indicates whether these ports are open or closed. Find out more about the Port Range Sensor.
  • Discover 195 more sensors in our sensor list. Our free trial version comes with the full selection of PRTG sensors. You can use this version to try all PRTG features for 30 days for free

Which ports does PRTG use?


PRTG needs certain ports to function properly. As an administrator, you will have to free up these ports. You will find an initial overview below. You can also find out more in our Knowledge base article: „Which ports do I need for PRTG?"

  • Web server: The web server requires TCP ports 80 (HTTP) and 443 (HTTPS), and uses fallback ports 8443, 32000+ (HTTPS), and 8080 (HTTP).
  • Reports: Have reports sent as PDF files. For this, port 8085 is required.
  • Auto-Update and Activation: Port 443 is required for Auto-Update and Activation
  • Update Check und Download: Port 80 is required for Update Check and Download.
  • Active Directory Integration: Here, ports 389 (TCP and UDP) and TCP 636 (SSL-secured) are used.
  • Remote Probes: Port 23560 is required for the connection between remote probes and the core server.
  • Cluster: Communication amongst cluster nodes takes place via port 23570.
  • PRTG Cloud: TCP port 443 is used to access the PRTG Cloud (e.g. for push notifications and the Cloud Ping and Cloud HTTP sensors).
  • SNMP: For SNMP, UDP port 161 is used.
Customer Quote Network Monitoring

"Our network engineers really love PRTG, because of its customization."

John Krull, CTO, Oakland Unified School District, USA

Download Network Monitoring Software for Windows - Version (March 28th, 2017)
Languages English, German, Spanish, French, Portuguese, Dutch, Czech, Russian, Japanese, and Simplified Chinese
Pricing Free for up to 100 sensors (Price List)
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Quote Daniel Elsner


 “With routers, switches, hubs, and bridges, your network has a great deal of ports which potentially need to be monitored. I would therefore recommend creating at least one active sensor per port on each of your central network components. By doing so, you should be able to monitor all of a network device’s active ports, as well as its CPU and RAM. On the other hand, for those network components which are not so vital, it is often sufficient to use paused sensors instead of actively monitoring every port.”

Daniel Elsner, PRTG Product Development

Award winning solution

We work hard on making our software as powerful and easy-to-use
as possible for our customers each and every day.
Of course it makes us proud when we get awards for that.



PRTG simplifies your day!

You have enough things to worry about.
Let the PRTG Network Monitor Tool monitor your entire network for you.

PRTG saves time

With PRTG, you get one central monitoring tool for measuring bandwidth and monitoring your ports. Enjoy a quick overview of your entire network via our dashboard and app.

PRTG saves worry

Installing PRTG is quick and easy. Getting started or switching from another network/bandwidth monitoring tool is easy thanks to its more than 200 predefined sensors.

PRTG saves money

PRTG is worth it. 80% of our customers report substantial savings in the area of network management. And license costs pay for themselves in an average of only 3 1/2 months.

The Swiss Army knife for admins

Adapt PRTG individually and dynamically, to your specific needs, using the API:

  • HTTP API: Access monitoring data and manipulate monitoring objects using HTTP requests
  • Custom Sensors: Create your own sensors for customized monitoring
  • Custom Notifications: Create your own notifications to send alarms to external systems



With PRTG, PAESSLER AG offers a powerful, affordable and easy-to-use unified monitoring tool. Over 150,000 administrators worldwide use our software, whether it be to monitor their server performance, virtual environments, or even the accessibility of their websites. PRTG is a network analysis solution for Windows.

Our network monitoring software was created in 1997 by Dirk Paessler. We are an established software company with headquarters in Nuremberg, Germany. We place great value on our high standards and never stop developing our software. And if ever there is an issue, our support team usually responds within 24 hours (except weekends). 

Get started with PRTG port monitoring today. You'll save time, money, and effort. It takes only a few minutes to install PRTG. You get 100 free sensors, which is plenty for small networks. And you can upgrade whenever you'd like.


Also interesting:


Bandwidth: How can I measure my bandwidth? How can PRTG help in difficult situations? How can I use PRTG to test my bandwidth? Find the answers to these and many more questions on our Bandwidth Monitoring page

Sensors: The concept of sensors is a central part of PRTG. In this four-minute video, you will get a basic idea of how sensors work and how best to use them.

LAN Monitoring: Whether LAN, WAN, or distributed networks: With PRTG, you get a constant overview of your entire network. The LAN Monitoring page provides information on the five pillars upon which this monitoring rests.

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