Paessler PRTG

Easy TCP monitoring that helps improve network security


  • Comprehensively monitor TCP ports and packets
  • Get real-time alerts & customizable notifications
  • View your TCP monitoring data at a glance

Our users give top ratings for monitoring with Paessler PRTG




PRTG makes TCP monitoring easy

Custom alerts and data visualization make it easy to monitor, identify, and prevent network issues.



TCP monitoring: The challenge


It‘s difficult to get a clear picture of network traffic in a large IT infrastructure in real time. This is especially true for virtualized and distributed traffic.

Establishing optimal performance metrics for networks that are constantly changing and scaling is also not that easy.

Displaying all the interdependencies in the network in an analytical form is a rather complex process.

The comprehensive TCP monitoring solution Paessler PRTG easily solves all these problems and provides you with convenient tools to monitor various aspects of TCP operations.


The solution: Easily monitor TCP using PRTG

Use our preconfigured PRTG sensors to monitor various parameters of TCP connections.


 i How PRTG defines sensors

In PRTG, “sensors” are the basic monitoring elements. One sensor usually monitors one measured value in your network, e.g. the traffic of a switch port, the CPU load of a server, the free space of a disk drive. On average you need about 5-10 sensors per device or one sensor per switch port.

View video (3:26 min.)


Monitor a network service by connecting to its port using a Port sensor that tries to connect to the specified TCP/IP port number of the device and waits for the request to be accepted. It allows you to monitor the port request acceptance time and downtime.

Connect to different TCP/IP ports and monitor network performance using the Port Range sensor. It allows you to determine the number of closed ports, the downtime, and the time of accepting a port request.

With the Port v2 sensor (in beta status), you can monitor a network service by connecting to one or more of its TCP/IP ports. Determine the number of closed and open ports, the number of errors, downtime, and the maximum time until a port connection request is accepted.

You can monitor the TCP ping time to the parent device from various locations worldwide via the PRTG Cloud with the Cloud Ping v2 sensor. These places are located on four continents of the globe.

PRTG checks whether TCP/IP ports are open or closed and sends customizable notifications to administrators. This significantly simplifies the process of ensuring network security because open ports put your network at risk.

What’s more: you don’t need to manually check which ports are closed and which are open anymore, which saves you a lot of time and effort.


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“The real beauty of PRTG is the endless possibilities it offers”


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Start TCP monitoring with PRTG and see how it can make your IT infrastructure more reliable and your job easier.


PRTG is compatible with all major vendors & manufacturers


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Visualize your TCP monitoring in real time





Three stages of TCP monitoring with PRTG



PRTG collects information about network devices and IP addresses and displays it graphically. This gives you a clear picture of your network traffic.


PRTG constantly monitors network connections to detect performance issues such as high latency, slow connection speed, etc.


With the monitoring data you collect with PRTG, you can analyze the received metrics and find and eliminate the causes of malfunctions.


PRTG makes TCP monitoring easy

Custom alerts and data visualization make it easy to monitor, identify, and prevent network issues.



Your TCP monitoring at a glance – even on the go

Set up PRTG in minutes and use it on almost any mobile device.


PRTG comes with all the features you need, plus more your IT infrastructure won't want to live without.



PRTG monitors these vendors and applications in one view!


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4 reasons why PRTG is the TCP monitoring tool of your choice

Enjoy all-in-one IT infrastructure monitoring

PRTG is a comprehensive monitoring tool for your whole network. It is easy to set up and configure. The TCP monitoring software allows you to track all important metrics and display them in a central dashboard so that you can quickly and conveniently view your monitoring data at a glance.

A plus: PRTG offers a free trial that includes all its sensors and features. This allows you to explore and test the software, set up TCP monitoring, and collect raw data for free. And if you want to switch from a different monitoring software, this is no problem as well thanks to the automatic network discovery and preconfigured device templates.


Be confident in the security of your data

PRTG uses modern data protection technologies to prevent intruders from gaining access to your monitoring data – for more network security for you. The main mechanisms used to protect your data from attacks are:

  • SSL encryption (HTTPS, TLS, Elliptic Curve Cryptography, Forward Secrecy)
  • Ability to allow or deny connections only from specific IP addresses
  • Using mechanisms to protect against cross-site scripting attacks, directory traversal attacks, and SQL injection attacks
  • A logout mechanism if the user is inactive for a long period of time and a re-authentication system to continue working
  • Ability to manage access rights for each user account and for each user group
  • And more


Easily configure sensors to monitor TCP

PRTG offers preconfigured sensors with default sensor settings that are easy to use. However, if you are not satisfied with the default values, you can easily change them at any time. There are basic settings that are the same for all sensors and specific settings for different types of sensors.

Get great support if you require it

Our extensive Paessler Knowledge Base contains a number of specific application tips and allows you to find answers to many of your questions. There are also instructions for setting up and using specific sensors. If you cannot solve your problem yourself, you can contact the Paessler Support team , which will answer all your questions within 24 hours.


PRTG makes TCP monitoring easy

Custom alerts and data visualization make it easy to monitor, identify, and prevent network issues.


PRTG the multi-tool

PRTG: The multi-tool for sysadmins

Adapt PRTG individually and dynamically to your needs and rely on a strong API:

  • HTTP API: Access monitoring data and manipulate monitoring objects via HTTP requests
  • Custom sensors: Create your own PRTG sensors for customized monitoring
  • Custom notifications: Create your own notifications and send action triggers to external systems
  • REST Custom sensor: Monitor almost everything that provides data in XML or JSON format


“Easy to implement and configure with good technical support.”

R. v. S., ICT Manager at Heinen & Hopman Eng BV


Start TCP monitoring with PRTG and see how it can make your network more reliable and your job easier.



Create innovative solutions with Paessler’s partners

Partnering with innovative vendors, Paessler unleashes synergies to create
new and additional benefits for joined customers.

IP Fabric

Combining the broad monitoring feature set of PRTG with IP Fabric’s automated network assurance creates a new level of network visibility and reliability.

Read more


Paessler and Plixer provide a complete solution adding flow and metadata analysis to a powerful network monitoring tool.

Read more


With ScriptRunner, Paessler integrates a powerful event automation platform into PRTG Network Monitor.

Read more


PRTG makes your job easier

Our monitoring software frees you to focus on other tasks by promptly notifying you of potential issues.


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Save effort

PRTG gives you one central monitoring tool for your servers and entire network. Enjoy a quick overview of your whole infrastructure via our dashboard and app.

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Save time

Getting started with PRTG is a breeze. Setting up or switching from another network monitoring tool is easy thanks to the auto-discovery and pre-configured device templates.

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Save money

80% of our customers report substantial cost savings with network monitoring. Your costs of licenses will likely pay for themselves within weeks.



We asked: would you recommend PRTG?
Over 95% of our customers say yes!


Paessler AG conducted trials in over 600 IT departments worldwide to tune its network monitoring software closer to the needs of sysadmins.
The result of the survey: over 95% of the participants would recommend PRTG – or already have.


Recommend PRTG


PRTG makes TCP monitoring easy

Custom alerts and data visualization make it easy to monitor, identify, and prevent network issues.


quote case study total uptime 2

“First, PRTG gives us the insight we need, telling us what is happening across our global network at any given moment. Second, the improved insight has increased our availability.“

Jonathan Hoppe, Co-Founder of Total Uptime // Read case study


FAQ: TCP monitoring



1. What is TCP and how does it work?

TCP stands for Transmission Control Protocol. It is a communication protocol used to connect network devices to the internet. In addition, it can be used as a communication protocol for a private intranet or extranet.

TCP keeps track of the data segments into which a message is divided for efficient routing through the network. It allows you to detect lost packets and packets that are delivered out of order, request redelivery, and reorder packet data.

2. Where is TCP used?

TCP is one of the primary ways of transferring data between network devices. It is used by many internet applications such as email, FTP, SSH, streaming media, and the World Wide Web.

3. What is TCP monitoring?

TCP monitoring is the process of tracking various parameters of network connections using the Transmission Control Protocol to find out about the status of the network, improve its performance, and correct errors.

TCP is a widely-used, high-performance internet protocol that is designed to exchange data between physically separated network devices. It guarantees the correct reception of data with high accuracy by keeping track of whether packets have arrived at the recipient. If the data is not received, the TCP packet is sent again.

TCP helps determine how packets are transmitted, addressed, routed, and received at their destinations.

4. What is a TCP monitor?

A TCP monitor is software that checks the health of network connections and devices.

5. Why do you need to monitor TCP connections?

Monitoring TCP connections is important in order to…

  • Be sure that a connection to a given IP address on a given port is possible
  • Determine how long it takes to connect to a given IP address
  • Get early notifications about errors such as a broken site, misconfigured firewall, etc.
  • Analyze network traffic
  • Identify and correct problems with the performance of connecting network devices
  • Monitor and analyze network traffic usage
  • Detect whether a system is dropping packets
  • Display network statistics on a per-protocol basis
  • Monitor the packet transfer process

6. What metrics can I track with PRTG TCP monitor?

Depending on the target device, available components, and sensor settings, the list of metrics that you can monitor using PRTG sensors can slightly differ. The main metrics you can get when monitoring TCP are:

  • Availability - the time until a request to a port is accepted in milliseconds
  • Downtime - the amount of time in which the sensor was down
  • Open ports - the number of open ports
  • Closed ports - the number of closed ports
  • Errors - the number of errors
  • Maximum connect time - the maximum time until a request to connect to a port is accepted
  • Location - the response time of the target server at the location

7. Are TCP connections secure?

TCP transports streaming data that is used at the application layer. It cannot protect segment data from message eavesdropping attacks. TCP does not provide any data encryption features, so attackers can easily obtain any important information. This protocol also cannot protect the connection from unauthorized access attacks.

8. What is a sensor in PRTG?

In PRTG, “sensors” are the basic monitoring elements. One sensor usually monitors one measured value in your network, for example the traffic of a switch port, the CPU load of a server, or the free space on a disk drive.

On average, you need about 5-10 sensors per device or one sensor per switch port.


Still not convinced?




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sysadmins love PRTG

Paessler PRTG is used by companies of all sizes. Sysadmins love PRTG because it makes their job a whole lot easier.


Monitor your entire IT infrastructure

Bandwidth, servers, virtual environments, websites, VoIP services – PRTG keeps an eye on your entire network.


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Paessler PRTG

Start TCP monitoring with PRTG and see how it can make your IT infrastructure more reliable and your job easier.




Network Monitoring Software - Version (April 10th, 2024)


Download for Windows and cloud-based version PRTG Hosted Monitor available


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Supported Vendors & Applications

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