Paessler PRTG

All-in-one NetFlow Analyzer PRTG


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    NetFlow Analyzer PRTG analyzes your bandwidth & traffic

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    PRTG supports all different NetFlow versions
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    PRTG analyzes all important Flow protocols

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    The PRTG NetFlow Analyzer saves and processes flows







Get a holistic view of your network with NetFlow Analyzer

 i NetFlow is a protocol for collecting, aggregating and recording traffic flow data in a network. NetFlow data provide a more granular view of how bandwidth and network traffic are being used than other monitoring solutions, such as SNMP. NetFlow was developed by Cisco and is embedded in Cisco’s IOS software on the company’s routers and switches and has been supported on almost all Cisco devices since the 11.1 train of Cisco IOS Software.
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NetFlow Analyzer PRTG lets you check and monitor your bandwidth and determine, for example, the amount of network traffic caused by IP addresses, protocols, or programs. In order to carry out such an analysis, you'll configure your routers such that flow packets are sent to a computer with a PRTG probe. NetFlow technology puts little strain on your CPU and is especially adapted for networks with heavy data traffic and bandwidth.

NetFlow protocol is mainly supported by Cisco routers and switches.

What is NetFlow monitoring?

NetFlow monitoring lets you analyze your network traffic and get a picture of network traffic flow. This can help you understand which process, user, or application may cause speed problems or network outages.

With the PRTG NetFlow Analyzer you can get a holistic view of your network, keep an eye on your network traffic and what your bandwidth is being used for.


This is how the free NetFlow Analyzer PRTG works


PRTG: A NetFlow analysing software, without any additional costs

 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.)

 No upgrade necessary

No upgrade necessary

PRTG is an all-in-one tool! The network monitoring tool requires no additional upgrade or tool to analyze your bandwidth using Cisco NetFlow. All it takes is a standard PRTG configuration and you’ll be on your way to monitoring the entire traffic which passes via your routers and switches.

 One tool for everything

One tool for everything

With PRTG, you get one central software solution for all of your monitoring topics – and a complete overview. The need for a combination of many different tools is a thing of the past. PRTG lets you monitor your bandwidth use, server, CPU, traffic analysis, website, cloud services, and much more. And can be used as a professional NetFlow Analyzer software, as well.

 Quick configuration

Quick configuration

PRTG uses an intelligent Auto Discovery to automatically set up comprehensive monitoring, and creates all the sensors you need. Switching from other NetFlow Analyzer software to PRTG therefore takes no time at all.



By default, Toplists in PRTG always split up the traffic analysis within the sensor among Top Talkers (bandwidth use according to IP address), Top Connections (according to connection), and Top Protocols (according to protocol). With Toplists, you’ll enjoy a categorized overview which makes NetFlow traffic analysis easy.


quote markus puke

“We can all work with greater peace of mind knowing
that our systems are constantly being monitored.”

Markus Puke, Network Administrator, Schüchtermann Klinik, Germany


PRTG sensors for NetFlow analysis

Netflow V5 sensors

NetFlow version 5 is in widespread use. With PRTG, you get a compatible NetFlow v5 sensor, as well as a NetFlow v5 (Custom) sensor.

Netflow V9 sensors

NetFlow version 9 is an advanced form of NetFlow technology. PRTG provides you with appropriate sensors for its use: the NetFlow v9 sensor and NetFlow v9 (Custom) sensor.

IPFIX sensors

Internet Protocol Flow Information Export (IPFIX) is an advanced form of Cisco's NetFlow system. PRTG offers two sensors for its use: The IPFIX sensor and IPFIX (Custom) sensor, which you can customize to meet your own specific needs.


This is what NetFlow analysing looks like in PRTG



NetFlow Analyzer PRTG – 3 useful applications

PRTG lets you recognize if your switches are not equipped to handle the quantity of data of your backup solution, before they become completely overloaded.
Should these switches overload during a backup anyway, PRTG NetFlow Analyzer will enable you to quickly find the perpetrator.


Identify bandwidth hogs

Identify bandwidth hogs

Individual sources often use disproportionately high amounts of network bandwidth. These sources may be individual users, but also applications or specific data. With our NetFlow traffic analyzer software, you’ll evaluate IP addresses and get complete traffic analytics.

Spot load peaks early

Spot load peaks early

Many companies experience fluctuations in access to various websites or internally-used applications. Define your own thresholds with PRTG NetFlow Analyzer so you can be informed early: ideally, before the performance of your system takes a hit.

Avoid backup overloads

Avoid backup overloads

Thorough backups can lead to problems for the entire network. Such problems are frequently the result of individual routers or switches which overload during the backup and thwart the entire network. Use NetFlow Analyzer PRTG to monitor the complete traffic and bandwidth and find the causes, and thereby optimize your network.


gerald schoch

Practical tip: “Hey Gerald, what would you tell administrators looking to use PRTG as a NetFlow Analyzer?”

“Cisco has continuously developed the NetFlow technology. Administrators must therefore find out beforehand which NetFlow version is supported by their routers and switches. With the right PRTG sensors, setting up NetFlow monitoring is quick and easy.”

Gerald Schoch, technical editor at Paessler AG


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.



Trusted by 500,000 users and recognized
by industry analysts as a leader


“Fantastic network and infrastructure monitoring solution that is easy to deploy and easier still to use. Simply the best available.”

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“Software is absolutely perfect, Support is superior. Meets all needs and requirements, this is a must have solution if you are needing any form of monitoring.”

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“The tool excels at its primary focus of being a unified infrastructure management and network monitoring service.”

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NetFlow Analyzer PRTG: Setup in 3 simple steps!

Configure the router's NetFlow protocol so it sends NetFlow packets to the computer running the PRTG Network Monitor:



Alternative: If you do not require long-term traffic analyses for every single PC and would only like to monitor the network traffic occurring presently and recently on the basis of IP or protocol, then creating a NetFlow sensor and correspondingly analyzing the data traffic in the Toplists based on IP or protocol is sufficient. More information on setup: search answers to user questions in our Knowledge Base. In this article, you'll find additional tips on the configuration of Cisco routers.

Configure PRTG

Configure PRTG

Configure PRTG. All Flow sensors are even available in the free trial version of PRTG. Choose a suitable license to enjoy comprehensive NetFlow traffic monitoring with over 200 types of sensors. You can do this at a later time.


Configure your router or switch

Configure your router or switch

Configure your Cisco router or switch so that it exports and sends NetFlow data to a computer running a PRTG probe. In the next step, you'll create the NetFlow sensor on this computer. Pay special attention to the Flow version which is exported. A compatible sensor must be used for traffic analysis and bandwidth monitoring via NetFlow in PRTG.


Create sensors

Create sensors

Create NetFlow sensors which are appropriate for the exported Flow version and target address and configure the UDP port and an IP address in the sensor settings where you would like the flows to be received. Another option is to indicate the IP address of a specific Cisco device if you would like the flows to be received by such a device, and turn on sampling mode if you have set this mode on the target device. Enter a value for the Active Flow Timeout which is at least one minute longer than that of the device. Finally, choose which of the sensor's data traffic categories should be displayed in PRTG NetFlow Analyzer, and define an optional filter for the desired data.


Netflow Analyzer for VMware

VMware and NetFlow

VMware uses NetFlow technology in the "vSphere Distributed Switches (vDS)" product line. In principle, these virtual switches connect the virtual network cards of virtual machines (VMs) to the network by way of the physical network cards of hosts. VMware has incorporated NetFlow for these virtual switches.

Monitoring with PRTG

Both monitoring and the NetFlow traffic analysis of physical (Cisco) devices are operational here. Set up NetFlow in the VMware vCenter and configure it such that these flows are sent to PRTG NetFlow Analyzer, where a corresponding flow sensor displays and monitors the data. As long as the correct NetFlow version is used, it will make no difference to PRTG where the flows come from.

Further information

All you need to know about VMware Monitoring with PRTG.


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


Other Flow sensors

PRTG provides other Flow sensors which allow you to monitor your chat protocols, Citrix, FTP, Email, and other traffic.

sFlow: With an sFlow sensor, only every nth packet will be passed on: this results in even less load on the system. Find our more about the PRTG sFlow sensor here.

jFlow: jFlow lets you monitor Juniper Networks hardware, among others. Here too you can configure devices especially for PRTG. It features a high degree of similarity to NetFlow5. Find out more about our jFlow sensor.

 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.)



Netflow, SNMP, Packet Sniffing


SNMP (Simple Network Management Protocol) is extremely popular and an easy way to read device data. It gives you an important first look, e.g. on bandwidth use, CPU, or the temperature of your hardware. More on SNMP monitoring with PRTG.

Packet sniffing

For more detailed information on your bandwidth usage, use Packet Sniffing or NetFlow. You will thus be able to take a closer look at the packets passing through individual routers or switches. More on Packet Sniffing with PRTG.

NetFlow analysis

NetFlow is a protocol supported in particular by Cisco hardware. You therefore need a monitoring solution which is compatible with NetFlow. Such a solution (Packet Sniffing, e.g.) will enable you to analyze packets in detail. PRTG comes with a set of NetFlow sensors - at no extra charge.


NetFlow collector vs. NetFlow analyzer

1. What are the best netflow tools?

Many tools can collect and analyze flow data. When choosing a NetFlow analyzer tool, you should consider your needs, and the extent to which you would like to analyze your data. It might also make sense to use several different tools concurrently. We have found, for example, that many administrators use Wireshark in addition to PRTG. Thanks to its flow monitoring, PRTG can give you an overall picture while allowing you to rule out possible causes of network problems. Wireshark, on the other hand, offers a detailed look at individual data packets.

2. What is a NetFlow collector?

A NetFlow collector captures, saves, and processes NetFlow data. Some of these tools are more effective than others at providing in-depth data analysis. Many administrators, however, use one single tool to perform the functions of both NetFlow collectors and NetFlow analyzers.

3. What is a NetFlow analyzer?

PRTG is a NetFlow collector AND a NetFlow analyzer. It captures and processes all NetFlow data, and presents this data on a dashboard. PRTG takes advantage of the toplists described above to display top talkers, top connections, top protocols, and customizable toplists. You are free to set your own threshold values. If these values are exceeded, PRTG will alert you at once.

4. What NetFlow analyzers and connectors are available for Windows?

PRTG is a NetFlow Analyzer & collector that runs on Windows. As our focus has always been on Windows systems, we have acquired quite a bit of expertise in the area of NetFlow traffic analysis with Windows. PRTG is your all-in-one Windows monitoring solution. It comes with numerous WMI sensors, as well as Windows Event Log monitoring and security monitoring. It also uses technologies which will enable you to monitor non-Windows operating systems.

5. NetFlow analyzer download: Free or professional?

Many administrators wonder if there is an effective free NetFlow Analyzer tool, or if they should consider using a professional one. PRTG comes with 100 free sensors which never expire. And if you decide to expand your monitoring in the future, a professional license can be purchased at any time. PRTG licenses let you enjoy all the software’s features: alarm, reports, support, and the full range of sensors.


Create innovative solutions with Paessler’s IT partners

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


By integrating PRTG with Martello iQ, you can add a fast analytics layer to improve uptime, visualize your IT environment, and integrate all of your IT systems into a single pane of glass.

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

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UVexplorer integrates tightly with PRTG to bring fast and accurate network discovery, detailed device inventory, and automatic network mapping to the PRTG platform.

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dirk paessler

“Our top priority is to continue to develop PRTG is a constant, practical, and proactive manner. Our hope is that administrators will always be ready for any new standards which arise.”

Dirk Paessler, founder of Paessler AG in Nuremberg


Still not convinced?



More than 500,000 sysadmins love PRTG

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

Still not convinced?


Monitor your entire IT infrastructure

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



Try Paessler PRTG for free

Everyone has different monitoring needs. That’s why we let you try PRTG for free. Start now with your trial.




Network Monitoring Software - Version (November 29th, 2022)


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


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Up to 100 sensors for free (Price List)

Unified Monitoring

Network devices, bandwidth, servers, applications, virtual environments, remote systems, IoT, and more

Supported Vendors & Applications

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