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The Best Free sFlow Collectors and Analyzers to Monitor your Network

the best free sflow collectors and analyzers

Marc Wilson UPDATED: January 4, 2024

Utilizing an sFlow Collector and Analyzer is essential as our reliance on network connectivity and the need for faster, reliable data transfer speeds grows, network administrators are under a lot of stress to ensure their network is performing at its peak.

Even the smallest changes on a network can affect its performance and reliability.

The sFlow protocol was designed to operate at the Layer2 level of the OSI model, and it comes embedded in a software process in switches and routers.

The sFlow Agent combines interface counters and flow samples, embeds them into an sFlow Datagram, and sends them on to an sFlow Collector.

Here is our list of the best free sFlow collectors and analyzers to monitor your network:

  1. SolarWinds NetFlow Traffic Analyzer – EDITOR'S CHOICE A package of bandwidth analysis systems that can communicate with network devices through sFlow, NetFlow, J-Flow, NetStream, and IPFIX, As well as general traffic analysis capabilities, this tool is able to monitor and manage VMWare vSphere virtual switches. Runs on Windows Server. Start a 30-day free trial.
  2. Paessler PRTG – FREE TRIAL A collection of monitoring tools that includes a network traffic data collection sensor that specifically communicates with sFlow. Installs on Windows Server. Start a 30-day free trial.
  3. ManageEngine NetFlow Analyzer – FREE TRIAL This bandwidth analyzer includes traffic monitoring systems that can interpret sFlow, J-Flow, NetFlow, IPFIX, NetStream, and AppFlow messaging. Installs on Windows Server and Linux. Start a 30-day free trial.
  4. Site24x7 – FREE TRIAL Offers intuitive real-time collection and analysis of sFlow data, complete with customizable alerts, sFlow analysis, and in-depth reporting making it an essential asset for network administrators and IT professionals monitoring network traffic. Start a 30-day free trial.
  5. sFlowTrend by inMon This specialist sFlow communicator is free to use and will help you sample traffic flow data from switches. Available for Windows and Linux.
  6. Plixer Scrutinizer This is the free version of a traffic sampling tool from Plixer. A paid version with more features is also available. Installs on top of Hyper-V.
  7. nTop A respected free traffic analyzer that can communicate through sFlow and NetFlow. Installs on Windows.
  8. Wireshark A widely downloaded packet capture system that can communicate through sFlow and NetFlow. Installs on Windows and macOS.
  9. Intermapper This is a network traffic analyzer that can be extended to use traffic flow protocols sFlow, J-Flow, and NetFlow. Installs on Windows, macOS, and Linux.

This information is used by network administrators to monitor and analyze network traffic via a free network analyzer tool in order to find issues and to stop them before they become major problems.

sFlow data can help pinpoint network bottlenecks, bandwidth hogs, and network problems, and the data contributes to helping the constant effort to improve network reliability.

The same sFlow data is also used by network security engineers to search for abnormal traffic patterns, such as large file transfers to a remote server or an unusually high number of connections to a local host initiated at once.

The Best sFlow Collectors

Our methodology for sFlow Collectors and Analyzers

We reviewed various sFlow collectors and analyzers and analyzed the options based on the following criteria:

  • Support for various flow protocols (sFlow, NetFlow, etc)
  • Ease of use
  • Graphical interpretation of data, such as charts and graphs
  • A free trial period, a demo, or a money-back guarantee for no-risk assessment
  • A good price that reflects value for money when compared to the functions offered

1. SolarWinds NetFlow Traffic Analyzer – FREE TRIAL

Best Free Sflow Collector Solarwinds screenshot and download

This free sFlow Collector Tool from SolarWinds is one of the best and most popular sFlow collectors available.

This tool allows you to sort, graph, and display data in various ways that allow you to easily visualize and analyze your network traffic.

This information can be used to identify which users, applications, and protocols are using the most bandwidth over a particular amount of time, and to find traffic patterns, which can be used to optimize network conditions during high-use periods.

SolarWinds NTA lets you drill down to a particular moment when something happened, which is invaluable for troubleshooting purposes.

Its query function can be invaluable when working to pinpoint problems and its real-time reporting and summaries provide important performance metrics that can ultimately help you save money by maximizing your network’s performance.


  • Supports multiple protocols like NetFlow, great for monitoring Cisco equipment
  • Both tools work well alongside each other to help view traffic patterns and bandwidth usage
  • Easy-to-use interface automatically highlights bandwidth hogs and other network traffic outliers
  • Scales well, designed for large enterprise networks
  • Can view traffic on a per-hop basis, allowing for granular traffic analysis


  • Built for enterprise use, not designed for small home networks

Its interface is easy to use and the data is collected and graphed in easy-to-read formats. SolarWinds NetFlow Traffic Analyzer’s sFlow Collector is an essential free tool for any network administrator.

4. Site24x7 – FREE TRIAL

Site24x7 sFlow Dashboard

In the realm of network management, particularly when dealing with sFlow data for performance monitoring, Site24x7 emerges as a competent and reliable tool. sFlow is essential for understanding network usage patterns, pinpointing bottlenecks, and ensuring efficient network performance. Site24x7 offers an intuitive way to collect and analyze sFlow data, making it a valuable asset for network administrators and IT professionals who need to monitor network traffic in real time.

Key Features

  • Real-time sFlow data collection and analysis
  • Comprehensive dashboard with detailed traffic insights
  • Customizable alerts for network anomalies
  • In-depth reporting capabilities
  • Support for multiple network protocols

Why do we recommend it?

We recommend Site24x7 as it provides an integrated platform for sFlow data analysis, offering real-time insights and detailed reports. Its ability to handle large volumes of data with ease makes it stand out in the category of free sFlow collectors and analyzers.

Who is it recommended for?

Site24x7 is particularly suited for network administrators and IT professionals in medium to large enterprises who require a robust and scalable solution for network traffic monitoring. Its comprehensive features cater to those who need in-depth traffic analysis and real-time monitoring for complex network environments.


  • Efficient real-time monitoring of network traffic
  • User-friendly interface with comprehensive dashboards
  • Customizable alert system for immediate anomaly detection


  • May be overwhelming for small-scale networks or beginners due to its extensive features

Site24x7 sFlow Monitoring Start a 30-day FREE Trial

5. sFlowTrend by inMon

sFlowTrend Collector & Analyzer by inMon

This free server-monitoring tool uses the sFlow standard to generate real-time displays of network bandwidth usage and of the top users and applications that are using this bandwidth. It allows you to rapidly find and identify the causes of problems on the network so that you can fix them before they become major problems.

With sFlow Trend, network administrators can also monitor critical host performance parameters, such as CPU usage and memory usage. Its graphical reports provide crucial information on current and historical performance, allowing you to identify bottlenecks, bandwidth hogs, and other troublemakers on your network.

Its simple installation and setup let you use less time on configuration and more time helping you improve your network. sFlowTrend supports Windows 32-bit and 64-bit OS’s, as well as Mac OS X, and Linux.


  • Completely free server monitoring tool
  • Offers simple graphics visualizations
  • Supports cross-platform (Windows, Mac, Linux)


  • Could use an overhauled UI

The free version provides support of up to five switches or hosts and stores one hour of data; with the sFlowTrend Pro version, there is not limit to the number of hosts or the amount of stored data. For more information and to download, please click here.

6. Plixer Scrutinizer Free

plixer sflow Traffic Analyzer

Scrutinizer is a powerful free network traffic analysis tool that uses sFlow, along with other flow technology protocols, to collect and analyze network traffic.

It allows you to troubleshoot your congested network by identifying problem stations, switches, routers, and other devices and applications.

Scrutinizer allows you to filter in on specific traffic in a number of ways, including a time frame, host, application, protocol, and much more.


  • Offers multiple deployment options
  • Designed to support large enterprise networks
  • Offers additional security-related traffic analysis features


  • Must reach out to sales for pricing
  • Steeper learning curve than similar tools on the market

This free edition allows for the collection of flows from unlimited devices and up to 10,000 flows per second, and stores up to 5 hours of data. Paid editions support flow collection of up to 8 million flows per second and unlimited history storage. For more information and to download, please click here.

7. nTop

ntop sflow collector

This popular software comes with powerful sFlow capture and analysis capabilities via its nProbe tool. It captures sFlow flows and converts them into “standard” flows, which it uses to generate reports and analyses.

What’s more is that it can capture any combination of flows on networks that use different devices like Cisco routers and switches, which use NetFlow. It combines these flows into integrated reports so that users do not have to sort through different data collected from different devices with different flow technologies.

Other features include IPv6 support, packet capture and sampling, VoIP traffic analysis, fully user configurable, and more.


  • Extremely lightweight tool
  • Supports IPv6
  • Combines flows so you have a holistic view of your data


  • Almost no visualization features

This popular and very powerful sFlow collector and network analyzer is definitely worth trying out. For more information and to download, please click here.

8. Wireshark

wireshark for sflow collection

Wireshark is a powerful, free, open-source network flow collector and analyzer. Using the sFlow sampling technology, Wireshark can capture and display detailed packet data for a network administrator or network security engineer to analyze.

Packet data can be filtered and colorized by categories to better read the data as it comes in, and that data can be saved and searched for future reference. It supports flow data capture from any number of wired, wireless, and virtual interfaces. Wireshark also supports different flow standards, such as NetFlow, jFlow, and all other major flow standards.

It comes with a graphical UI as well as a text-only interface, TShark, which allows for scripting. It supports Windows XP and higher, as well as OS X, Linux, and others.


  • Massive open-source community keeps the software updated and new features are added periodically
  • Built by network professionals, for network professionals
  • Can save captured packet data for further analysis or archival purposes


  • Not user-friendly, designed for network administrators
  • Steep learning curve, even for those who use IT products regularly
  • Pulls all data over the network unless intentionally filtered out

Wireshark is a must-try-free tool for any network administrator. For more information and to download, please click here.

9. Intermapper

intermapper sflow software

Intermapper is an industrial-strength network monitoring, mapping, and alerting application designed to help you manage your network and keep it at its optimum performance level.

Intermapper’s integrated network analyzer tool collects historical network flow data and saves it for you to identify current and past network activity trends; its interface allows you to easily chart this data in ways that makes it easy to visualize.

Using sFlow data, Intermapper helps you address security concerns such as identifying your Top Talkers, which websites were visited most often, which local IP addresses are connecting to an unusually large number of hosts, and which devices uploaded unusually large files to an off-site host.

Real-time flow monitoring, bandwidth monitoring, and network mapping capabilities are some of the many features included in Intermapper.

You can also capture new network devices as they connect to the network.

Intermapper scans your network to show any outbound devices that have connected, giving you a more accurate picture of all Layer 3 devices on your network, so you can add new devices to the maps for continued monitoring.

New device discovery helps enhance your network security and gives you awareness of what’s connected to your network at all times.


  • Offers a free and paid version
  • Is capable of using auto-discovery to find new devices
  • Features SLA compliance reporting, good for MSPs and larger networks
  • Available on Window, Linux, and Mac, making it a flexible option across multiple operating systems


  • The interface feels outdated, making it difficult to navigate at times
  • Visual options are limited
  • Maps are generally not visually appealing, and not great if used in a presentation

More info Here – Download a free 30-day trial


That concludes our list of sFlow software that we recommend to anyone looking to monitor their network devices that are capable of it.

With sFlow technology, we are able to make our networks faster, more reliable, and more secure.

This list of the Best sFlow Collectors and Analyzers will let you easily implement this technology on your network so that you can quickly start taking advantage of its benefits.

Free sFlow Collectors and Analyzers FAQs

Why use an sFlow collector?

sFlow collectors are used to monitor network traffic and performance, and provide valuable information about network utilization, traffic patterns, and security threats. By using an sFlow collector, organizations can gain a more complete view of their network traffic and performance, allowing them to make informed decisions about network management and security.

What are the key features of an sFlow collector?

The key features of an sFlow collector include:

  • Data aggregation: The ability to collect and aggregate sFlow data from multiple network devices into a centralized repository.
  • Data analysis and reporting: The ability to analyze and report on the collected sFlow data, providing valuable insights into network performance and utilization.
  • Scalability: The ability to support the collection of sFlow data from large and complex network environments.
  • Integration with other tools: The ability to integrate with other network monitoring and management tools, such as network analyzers and security information and event management (SIEM) systems.

Check out other related articles here:

Top Open Source sFlow Collector and Analyzers

Netflow vs sFlow? Whats the Difference

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