For some time, NetFlow analysis has been one of the core strategies relied on by IT administrators to conduct real-time network monitoring. So much of an enterprise-grade service’s reliability rests on its bandwidth performance. It is in this area that NetFlow analyzers are worth their weight in gold. With a NetFlow analysis tool, an administrator can see how efficiently data is transferred across a network without relying on the large volumes of stored data that regular packet capture procedures create.
Here is our list of the best free NetFlow analyzers:
- ManageEngine NetFlow Analyzer (FREE EDITION) This paid traffic analysis system uses NetFlow as well as other traffic protocols and is available in a Free edition. Runs on Windows Server and Linux. Start a 30-day free trial.
- Site24x7 Network Monitoring (FREE TRIAL) This cloud service implements network device monitoring and traffic analysis and is packaged with other system monitoring services. Start a free 30-day trial.
- Paessler PRTG Network Monitor (FREE TRIAL) This full stack monitoring package includes NetFlow analysis and free for up to 100 sensors. Runs on Windows Server. Start a 30-day free trial.
- SolarWinds NetFlow Traffic Analyzer This on-premises package is available as an addition to the Network Performance Monitor and it provides traffic analysis with NetFlow and other flow statistics protocols. It runs on Windows Server.
- ntopng A paid packet sniffer that includes a traffic analysis feature and has a free Community edition. Available for Windows, Unix, Linux, and macOS.
- Plixer Scrutinizer A paid traffic collector and NetFlow analyzer that has a free version. Runs on Hyper-V or VMware.
- The Dude A free network discovery and mapping tool that is based on SNMP. Runs on Windows, macOS, and Linux.
- WireShark This free packet sniffer has its own searching and filtering language and enables extensive traffic analysis. Runs on Windows, macOS, and Linux.
- FlowScan This free network analyzer can show time series graphs of traffic throughput and store traffic attributes in a database. Runs on Linux or Unix.
- sFlow Toolkit A free analyzer for packet data that works on a tcpdump input and generates sFlow-format records. Runs on Linux and Windows.
- Colasoft Capsa A protocol analyzer with paid and free editions that displays graphs of traffic data. Runs on Windows.
From a glimpse, you can identify whether your network is performing as it should be or whether an underlying issue is decreasing the standard of service. In a nutshell, deploying a NetFlow analyzer helps determine whether a network is experiencing poor performance, and it conducts troubleshooting if a problem is found. In this article, we look at the best free NetFlow analyzers on the market.
What is a NetFlow Analyzer?
NetFlow is the term given to a network protocol designed by Cisco to collect IP traffic and conduct network monitoring. NetFlow analyzers collect data generated by devices throughout the network and allow the user to view historic and real-time perspectives of the network.
When viewed with a NetFlow analyzer, the data obtained from network devices reveals key details like port numbers and IP addresses. More importantly, it allows you to view the source and destination of all NetFlow traffic. Each device must enable NetFlow in order to see NetFlow data.
Why Do I Need a Netflow Analyzer?
A NetFlow analyzer offers you one of the best tools to take stock of what is happening on your network. It allows you to interpret real-time and stored traffic data from your network and look for causes of poor connectivity. This helps to make sure that you don’t experience downtime on account of unresolved issues. The main reasons why administrators use Netflow Analyzers are listed below:
- Develop a network inventory – Auto discover devices on your network and map out network infrastructure.
- Analyze a network in real-time – Viewing live traffic on your network and looking out for signs of poor performance.
- View historical traffic data – View old usage statistics to develop further insights into your connection.
- Notifications – Receive notifications when network problems are detected, e.g latency or compromised devices.
The Best Free NetFlow Analyzers
1. ManageEngine NetFlow Analyzer (FREE TRIAL)
ManageEngine NetFlow Analyzer is a network analyzer that has become a staple in the toolkit of many administrators. NetFlow analyzer can tell you almost everything about your network down to devices, conversations, and interfaces along with their volume, utilization, and speed. All this information is translated into visual formats like graphs so you can find out exactly what’s going on.
Key Features:
- Real-Time Traffic Monitoring: Delivers live visibility into network bandwidth and traffic patterns.
- Application & Protocol Insights: Breaks down traffic by application, port, and protocol for detailed analysis.
- Customizable Dashboards: Users can configure views to highlight key performance indicators and trends.
- Threshold-Based Alerts: Sends real-time alerts when traffic or bandwidth usage exceeds defined limits.
- Detailed Reporting Engine: Offers scheduled and on-demand reports to track usage trends and spot anomalies.
Why do we recommend it?
ManageEngine NetFlow Analyzer stands out as an essential network analyzer, offering a comprehensive view of your network’s intricacies, including devices, conversations, interfaces, and their associated metrics. The platform translates this wealth of information into visually-intuitive graphs, enabling users to gain precise insights into network activities. Its real-time updating feature ensures dynamic monitoring of top interfaces, protocols, and conversations. Particularly beneficial for enterprise environments, NetFlow Analyzer provides automation features, allowing users to set customizable alerts based on defined traffic thresholds. The platform’s capacity for customized reporting and historical data analysis makes it a robust solution for in-depth diagnostics, fault correction, and network optimization.
Graphs and displays update in real-time, showing top interfaces, protocols, and conversations. This platform is great in an enterprise environment because it offers the user a number of automation features. For example, you can set the parameters of the alerts you see. If traffic goes above or below a defined level, you’ll be notified immediately. You don’t have to stay glued to the desk in order to stay up to date.
On the main screen, a breakdown of current alerts shows every warning that has been raised. Like PRTG, NetFlow Analyzer allows the user to develop custom reports. This allows you to run in-depth diagnostics and troubleshooting on your network based on the historical data you have available. This is useful for correcting faults and optimizing your network.
Who is it recommended for?
ManageEngine NetFlow Analyzer is recommended for administrators and IT professionals seeking a versatile network analysis tool suitable for both small and large-scale deployments. Its real-time monitoring capabilities and automation features make it particularly valuable for enterprises where staying informed about network performance is crucial. The ability to set custom alerts and generate detailed reports enhances its utility for proactive network management. Whether operating within an SME or a larger organization, ManageEngine NetFlow Analyzer proves effective in maintaining network visibility, optimizing performance, and facilitating prompt issue resolution.
Pros:
- Intuitive Interface: Easy to navigate, making it accessible even for teams new to NetFlow analysis.
- Deep Traffic Visibility: Provides granular insights into network behavior to support faster troubleshooting.
- Multi-Flow Compatibility: Supports NetFlow, sFlow, IPFIX, J-Flow, and more, making it broadly usable across devices.
- Responsive Support: Offers reliable assistance during setup or issue resolution.
Cons:
- Premium Pricing: Cost may be a barrier for small teams or budget-conscious organizations.
Overall this is a solid platform whether you’re operating within an SME or a larger organization. With the free trial version, you can monitor an unlimited number of interfaces. Unfortunately, you’ll be limited to two once the trial period ends. You can download a 30-day free trial.
2. Site24x7 Network Monitoring (FREE TRIAL)
The Site24x7 Network Monitoring module is part of full stack observability systems. This service provides network discovery and inventory creation. This service is provided by SNMP procedures, which constantly cycles to check on the availability and health of network devices, simultaneously checking on the current status of the inventory. The tool also draws up a network topology map.
Key Features:
- Automatic Device Discovery: Scans network ranges to detect devices automatically, reducing manual setup time.
- Multi-Vendor Compatibility: Supports a wide range of hardware vendors for seamless monitoring across heterogeneous networks.
- Predefined Device Templates: Includes thousands of templates to simplify configuration and performance tracking.
- Network Topology Mapping: Generates real-time Layer 2 and visual maps to understand how devices are interconnected.
- Environmental Sensor Support: Monitors hardware and environmental metrics via SNMP-enabled sensors for full visibility.
- Custom MIB Support: Allows uploading and monitoring of custom MIBs for specialized equipment or data points.
- VoIP Quality Monitoring: Tracks jitter, latency, and packet loss to evaluate voice service quality.
Why do we recommend it?
Site24x7 Network Monitoring earns our recommendation as an integral part of full-stack observability systems, offering robust network discovery and inventory creation. The service utilizes SNMP procedures for continuous checks on the availability and health of network devices, concurrently updating the inventory status and generating a comprehensive network topology map. Its traffic analysis service sets it apart, supporting a wide range of protocols such as NetFlow, sFlow, J-Flow, CFlow, IPFIX, AppFlow, and NetStream, ensuring compatibility with devices from various providers. Notably, the automated Quality of Service assessors for VoIP, incorporating IP SLA and MOS statistics, enhance the implementation of effective traffic shaping measures.
The traffic analysis service in the Network Monitoring package is able to communicate with network devices through the NetFlow, sFlow, J-Flow, CFlow, IPFIX, AppFlow, and NetStream protocols. This gives the system the ability to communicate with devices from any provider.
The traffic analysis system includes automated Quality of Service assessors for VoIP. These compile IP SLA and MOS statistics and protocol analysis that will help you implement traffic shaping measures.
Who is it recommended for?
Site24x7 Network Monitoring is recommended for organizations and IT professionals seeking a comprehensive solution for network discovery, inventory management, and traffic analysis. Its SNMP-based procedures make it versatile for monitoring the health and availability of network devices in real-time. The support for diverse protocols ensures compatibility with devices from different providers, making it suitable for environments with varied network infrastructure. The automated Quality of Service assessors specifically cater to VoIP requirements, making it an ideal choice for organizations prioritizing efficient traffic management and service quality optimization.
Pros:
- End-to-End Infrastructure Coverage: Covers everything from network devices to servers, cloud, and applications.
- Highly Customizable Dashboards: Adapts to unique operational needs through configurable metrics and visualizations.
- Strong Cloud & Virtualization Support: Monitors cloud environments and virtual systems with the same depth as physical devices.
- Intelligent Alerting: Uses AI to suppress alert noise and highlight the most important issues.
- Workflow Automation: Automates responses and daily checks, improving efficiency and reducing human error.
Cons:
- Steep Learning Curve: New users may need time to become comfortable with the breadth of tools and settings.
Site24x7 creates packages of its monitoring services and all of the include the Network Monitoring module. This is not a free system but you can use it for nothing by accessing the 30-day free trial.
3. Paessler PRTG Network Monitor (FREE TRIAL)
PRTG Network Monitor is as close to comprehensive as it gets in terms of network monitoring and NetFlow analysis. PRTG supports NetFlow, J-Flow and sFlow protocols making it versatile enough to function as a NetFlow tool in most organizations. Network Monitor has become a popular platform on account of its user interface. The navigation tree is very simple so that you can cut straight down to the minutiae of your network traffic.
Key Features:
- Flow-Based Traffic Monitoring: Captures and analyzes NetFlow, sFlow, jFlow, and IPFIX data to identify top talkers and bandwidth consumers.
- Customizable Flow Sensors: Offers specialized sensors like NetFlow V5/V9, sFlow, and IPFIX to suit different device types and traffic formats.
- Application-Level Traffic Insights: Distinguishes traffic by application, protocol, and IP, helping isolate performance issues and prioritize bandwidth usage.
- Toplists and Filters: Provides visual breakdowns of bandwidth usage per IP, conversation, protocol, or port, with filtering options for deep-dive analysis.
- Real-Time Traffic Graphs: Displays live network usage data with customizable dashboards for immediate visibility into flow data.
Why do we recommend it?
Paessler PRTG Network Monitor stands out as a comprehensive solution for network monitoring and NetFlow analysis, supporting NetFlow, J-Flow, and sFlow protocols. Its popularity is attributed to the user-friendly interface, providing a straightforward navigation tree that allows users to delve into the details of network traffic effortlessly. The setup process is equally hassle-free, featuring auto-discovery to identify active devices on the network. Notably, PRTG Network Monitor excels in automation, offering configurable alerts via email or SMS for prompt notification of NetFlow or network activity, enabling quick response. The product’s ability to translate data into various report formats adds to its versatility.
Likewise, the setup process is very easy. Auto-discovery finds active devices on your network. This automation is something that carries over into Paessler’s use of alerts as well. You can configure alerts to be sent to you via email or SMS. If PRTG Network Monitor clocks any Netflow or network activity on your network, alerts will be sent straight to you to take action. You can also translate your data into historic data reports in PDF, HTML, CSV and XML.
Who is it recommended for?
PRTG Network Monitor is recommended for organizations and individuals seeking a user-friendly yet comprehensive solution for network monitoring and NetFlow analysis. Its versatility in supporting various protocols, including NetFlow, J-Flow, and sFlow, makes it suitable for deployment in diverse network environments. The straightforward navigation and automation features make it particularly appealing to users who prioritize ease of use and quick setup. The availability of different paid products, in addition to the basic free version, caters to the varying needs and scales of organizations.
Pros:
- Broad Flow Protocol Support: Supports multiple flow technologies, making it suitable for diverse network environments.
- High Granularity: Offers detailed insight into traffic behavior, helping pinpoint bandwidth drains and potential bottlenecks.
- Integrated Monitoring: Combines NetFlow analysis with overall network, server, and application monitoring in one platform.
- Easy Visualization: Visual graphs and toplists make traffic analysis more digestible for all technical levels.
Cons:
- Sensor Limits in Licensing: Flow analysis may require multiple sensors, which can increase costs under the sensor-based licensing model.
Overall PRTG Network Monitor is a great product because of its usability. It’s incredibly easy to get started up and conduct NetFlow analysis. While the basic PRTG Network monitor is free, there are a number of different paid products as well. Paessler PRTG can be downloaded as a free trial.
4. SolarWinds NetFlow Traffic Analyzer
SolarWinds is a big name in the world of network monitoring, and NetFlow Traffic Analyzer is perhaps the most competitive packet monitoring solution available. This product allows the user to monitor their real-time network and bandwidth usage. You can view your network usage and also packet capture data through a web-based application.
Key Features:
- Bandwidth Utilization Monitoring: Tracks real-time bandwidth consumption across the network, identifying top users and applications.
- Application Traffic Analysis: Identifies and categorizes traffic by application, helping to pinpoint which applications consume the most bandwidth.
- Quality of Service (QoS) Monitoring: Evaluates the effectiveness of QoS policies, ensuring critical applications receive appropriate bandwidth.
- Customizable Alerts: Sends notifications when traffic patterns deviate from predefined thresholds, aiding in proactive issue resolution.
Why do we recommend it?
SolarWinds NetFlow Traffic Analyzer earns our recommendation as a top-tier packet monitoring solution, owing to its seamless real-time network and bandwidth usage monitoring capabilities. Recognized for its user-friendly interface, this product stands out for its ease of use and stripped-back design, allowing users to effortlessly comprehend their network status. The tool’s ability to generate real-time graphs displaying usage data provides immediate insights into bandwidth consumption by devices and applications. With automatic real-time updates, users can quickly assess network performance, making it an invaluable solution for efficient network monitoring.
One of the main selling points of NetFlow Traffic Analyzer is that it is easy to use. The stripped-back design of the user interface makes it easy to see what’s going on with your network. The tool generates graphs that display usage data in real-time. These graphs allow you to quickly determine which devices and applications consume the most bandwidth.
NetFlow Traffic Analyzer’s graphs update automatically in real-time, so you can immediately identify how well your network is performing. You can tell in a matter of seconds if your network experiences poor quality of service. This is one of the features that makes SolarWinds NetFlow Traffic Analyzer out top pick on this list.
Who is it recommended for?
This tool is recommended for network administrators and IT professionals seeking a comprehensive yet user-friendly solution for real-time network and bandwidth usage monitoring. SolarWinds NetFlow Traffic Analyzer’s intuitive interface makes it accessible to users with varying levels of technical expertise. Its suitability extends to enterprises of all sizes, offering valuable insights into network performance and aiding in identifying bandwidth-hungry devices and applications. Whether managing a small business network or a large enterprise infrastructure, SolarWinds NetFlow Traffic Analyzer proves to be an indispensable tool for optimizing network efficiency and addressing potential issues promptly.
Pros:
- In-Depth Traffic Analysis: Provides granular visibility into network traffic, aiding in identifying and resolving bandwidth issues.
- User-Friendly Interface: Features an intuitive dashboard that simplifies navigation and data interpretation.
- Scalability: Capable of handling large networks, accommodating growth without compromising performance.
- Multi-Vendor Support: Compatible with various flow protocols and devices from multiple vendors, enhancing versatility.
Cons:
- Learning Curve: New users may require time to fully grasp and utilize all features effectively.
This tool pack includes a simple interface to turn the NetFlow capabilities of your Cisco routers on and off. It also has a tool that replays stored traffic data so you can watch the performance of your network. A third utility will generate extra traffic so you can test your infrastructure in preparation for a planned increase in load on the network. Start a 30-day free trial here.
5. ntopng
ntopng has developed a reputation as one of the most formidable free network traffic monitors. This versatile tool runs on Windows, Unix, and Mac OS. ntopng runs through an encrypted web-based user interface that shows a real-time breakdown of active network traffic. The web-based console is great for organizations looking for fast and flexible deployment.
Key Features:
- Flow-Based Traffic Visibility: Monitors traffic using NetFlow, sFlow, and IPFIX without relying on full packet capture.
- Deep Packet Inspection (nDPI): Identifies and classifies traffic by application for granular analysis.
- Real-Time Traffic Monitoring: Displays live data on bandwidth usage, top talkers, and protocol breakdowns.
- Historical Traffic Storage: Keeps records of traffic data to enable long-term trend analysis and forensic investigation.
- Geolocation Mapping: Visually maps source and destination IP addresses to global locations for context-rich analysis.
Why do we recommend it?
ntopng is a highly regarded free network traffic monitor compatible with Windows, Unix, and Mac OS, praised for its versatility and real-time analysis. Its encrypted web-based interface ensures fast and flexible deployment, making it ideal for organizations prioritizing quick implementation. The tool offers detailed insights into active network traffic, including application-specific data and real-time latency analysis, enhancing its appeal for network administrators and users. The user-friendly interface provides various visual displays for comprehensive monitoring, and its low-maintenance nature makes it an excellent choice for those seeking a hassle-free NetFlow analyzer.
You can view NetFlow data in a variety of ways right down to active flows by application. You can also see how much latency you have on your network at one time. The platform does this by breaking down the networks 3-day handshake packets and calculating the time it takes for them to transfer. The latency is determined by how long it takes for the packets to move across the network.
The user interface either doesn’t fall short, either. You can choose a variety of visual displays to look at and comb through your historical data by time and date. This ensures you don’t miss anything and can make the necessary adjustments if you spot poor performance.
Who is it recommended for?
ntopng is recommended for organizations and individuals seeking a powerful, free network traffic monitor compatible with various operating systems, prioritizing quick and flexible deployment. Network administrators and users interested in gaining detailed insights into active flows, application-specific data, and real-time latency analysis will find ntopng particularly beneficial. The user-friendly interface and minimal configuration requirements make it accessible to a wide range of users, ensuring its suitability for both experienced professionals and those new to NetFlow analysis.
Pros:
- High Protocol Coverage: Works with multiple flow formats like NetFlow, sFlow, and IPFIX, increasing compatibility.
- Strong Application Awareness: nDPI engine provides detailed insights into app-layer traffic for better visibility.
- Open-Source Flexibility: Allows customization and is ideal for users who prefer open systems and scripting support.
- User-Friendly Web GUI: Provides a clean, browser-based dashboard with clear traffic summaries and drill-down options.
Cons:
- Requires External Flow Exporters: Needs tools like nProbe to collect flows from devices that don’t natively export them.
- Performance Demands: Processing high-speed traffic can be CPU-intensive, especially on less capable hardware.
- Advanced Configuration Complexity: Setting up custom views, filters, or integrations may require technical expertise.
The free version of ntopng is called the Community version and can be downloaded from here. Ntopng is highly recommended if you want to deploy a low-maintenance NetFlow analyzer that doesn’t need much configuration.
6. Plixer Scrutinizer
In terms of scalability, few products offer as much potential as Scrutinizer. Scrutinizer can function in a variety of SME and larger enterprise environments with the capacity to handle millions of flows per second. In addition, Scrutinizer offers a great user interface lets you delve down deep into the time frame, host application, and protocol of all your network elements. It’s also versatile in the sense that it supports NetFlow, sFlow and IPFIX.
Key Features:
- Multi-Protocol Flow Support: Captures and analyzes network traffic using NetFlow, sFlow, IPFIX, JFlow, and other flow technologies.
- Live Traffic Monitoring: Provides real-time visibility into bandwidth usage, enabling rapid response to congestion or performance issues.
- Centralized Flow Data Correlation: Aggregates flow records from across the network into a unified view, adding rich context to traffic analysis.
- Integrated Threat Detection: Detects abnormal patterns and potential threats using behavioral baselines and traffic flow analysis.
Why do we recommend it?
Plixer Scrutinizer stands out for its exceptional scalability, making it suitable for a wide range of environments, from SMEs to large enterprises, with the capability to handle millions of flows per second. The user interface is praised for its depth, allowing users to explore details such as time frames, host applications, and protocols for comprehensive network analysis. Supporting NetFlow, sFlow, and IPFIX, Scrutinizer showcases versatility in flow protocols. The reporting feature enhances data breakdown, providing valuable insights for further analysis. The unrestricted monitoring of interfaces in the free version makes Scrutinizer an excellent choice for seamless deployment within larger organizations.
Who is it recommended for?
Plixer Scrutinizer is recommended for organizations seeking a highly scalable network monitoring solution, suitable for both SMEs and large enterprises. The platform’s depth and versatility, supporting various flow protocols, make it ideal for network administrators and users who require comprehensive insights into time frames, host applications, and protocols. The free version’s unlimited interface monitoring capability adds to its appeal, making it well-suited for seamless integration into larger organizational setups.
Pros:
- Deep Traffic Visibility: Offers granular insights into who is using bandwidth, when, and for what purposes.
- Flexible Flow Compatibility: Works with a broad array of vendors and flow protocols, making it suitable for complex environments.
- Customizable Reports: Tailored reporting tools help align insights with business or technical goals.
- Enhanced Network Security Insight: Flow analytics support threat detection and forensic analysis across distributed networks.
- QoS & Capacity Planning: Helps fine-tune quality of service and assess infrastructure needs before upgrades.
Cons:
- Complex Report Configuration: Creating advanced custom reports may require deeper technical knowledge of flow data structures.
- Security Visibility Limited to IPs: Primarily tracks security issues based on IP addresses, without deeper URL or app-layer context.
- Manual Map Creation: Building visual network maps is a slow process and could benefit from more automation.
- Limited Long-Term Data Retention: May not retain historical data long enough for extensive forensic investigations.
A reporting feature breaks down NetFlow data for further analysis. Overall this is a great platform and the free version doesn’t restrict the number of interfaces you can monitor. As a result, it can be deployed seamlessly within a larger organization. Scrutinizer can be downloaded for free from here.
7. The Dude
MikroTiks’ The Dude is quite a famous name within the network monitoring community. This tool is considered to be one of the best value products available online. With support for SNMP, ICMP, DNS, and TCP, The Dude can function within even the most demanding network environment.
Key Features:
- Automatic Device Discovery: Scans your network to locate and map all connected devices without manual input.
- Custom Network Mapping: Enables creation of personalized visual layouts with custom icons and backgrounds for easier network navigation.
- Service and Uptime Monitoring: Monitors device services like HTTP, DNS, and SNMP, and alerts users when issues arise.
- Multi-Protocol Support: Uses SNMP, ICMP, DNS, and TCP protocols for broad compatibility with network hardware.
- Remote Management Integration: Offers built-in tools to access and control devices directly from the interface.
Why do we recommend it?
MikroTik’s The Dude earns recognition as a cost-effective and popular choice in the network monitoring community. With support for SNMP, ICMP, DNS, and TCP, it effectively operates in diverse and demanding network environments. The tool’s simplicity stands out, featuring an auto-discovery function that swiftly recognizes network devices, streamlining the deployment process. Additionally, The Dude facilitates map creation and offers a topological perspective based on the discovered information. While not as polished as SolarWinds NetFlow Traffic Analyzer, The Dude provides a competitive solution, making it a solid option for users seeking an easy-to-use and install network monitoring tool.
One of the draws of The Dude is that it is simple to deploy. An auto-discovery feature automatically recognizes devices on the network so you don’t have to spend time messing around with configurations. You can also use this information to draw up maps and create a topological perspective.
Who is it recommended for?
The Dude is recommended for users in search of a cost-effective and straightforward network monitoring solution. Its support for various protocols, including SNMP, ICMP, DNS, and TCP, makes it suitable for diverse network environments. The tool’s simplicity and auto-discovery feature make it particularly appealing for users who prioritize easy deployment and quick setup. While it may not have the sophistication of some premium tools, The Dude is a viable choice for those who value a competitive offering with broad compatibility, operating seamlessly on Windows, MacOS, and Linux.
Pros:
- Intuitive User Interface: Easy to navigate with drag-and-drop map creation, ideal for users with varied technical backgrounds.
- Device-Agnostic Monitoring: Can discover and manage devices from any vendor, not limited to a single brand.
- Flexible Alert System: Customizable alert options include pop-ups, sounds, and email notifications for quick response.
Cons:
- Performance Issues on Large Networks: Monitoring large-scale environments may strain system resources.
- Outdated Documentation: Limited and sometimes outdated support materials can hinder full use of advanced features.
Overall, The Dude is very easy to use and install. If you want a tool to hit the ground running, then this is a solid option. Though it is not as slick as SolarWinds NetFlow Traffic Analyzer, it still provides a competitive offering. The Dude operates on Windows, MacOS, and Linux. The Dude can be downloaded from here.
8. WireShark
WireShark is one of the most well-known NetFlow analyzer tools in the world. At one point or another almost every network administrator has dabbled with WireShark or considered it. WireShark’s core platform can conduct real-time NetFlow analysis on an enterprise scale. Most administrators use WireShark to identify when a bottleneck occurs.
Key Features:
- Protocol-Level Packet Analysis: Provides detailed inspection of hundreds of network protocols with deep visibility into packet-level data.
- Live Capture and Offline Review: Captures traffic in real time and allows for saving and analyzing it later.
- Cross-Platform Compatibility: Available for Windows, macOS, Linux, and other operating systems.
- Advanced Filtering Engine: Offers powerful display filters to zero in on specific packets or types of traffic.
- VoIP Traffic Analysis: Includes tools to analyze voice traffic quality and protocol-level details.
Why do we recommend it?
WireShark stands out as one of the most renowned NetFlow analyzer tools globally, widely used by network administrators. Its core platform excels in real-time NetFlow analysis, making it suitable for enterprise-scale applications. Network administrators leverage WireShark to pinpoint bottlenecks and capture diverse traffic types, including Wifi, Bluetooth, Ethernet, VLAN, and USB traffic. One notable feature is its powerful filtering capability, allowing users to focus on specific protocol traffic during netflow analysis, enhancing efficiency and troubleshooting efforts. WireShark is particularly recommended for those seeking a robust and free network analyzer with troubleshooting capabilities, applicable to both SMEs and larger organizations.
WireShark can capture Wifi, Bluetooth, Ethernet, VLAN, and USB traffic from devices across a network. This helps produce a complete perspective of an entire network. One particularly useful feature offered by WireShark is that of filters. Display filters determine what type of protocol traffic is displayed when analyzing netflows.
This is an extremely useful feature because it can often be incredibly difficult to manually sift through thousands of NetFlow processes on an active enterprise network. It also helps in regards to troubleshooting. As such, if you require a network analysis tool that is built with troubleshooting in mind, then give WireShark a try.
Who is it recommended for?
WireShark is recommended for network administrators and professionals at various levels who require a powerful and free network analyzer tool. Its capabilities cater to both small and large organizations, making it versatile for different network environments. The tool’s effectiveness in real-time NetFlow analysis, coupled with the ability to capture diverse types of network traffic, positions it as a valuable choice for those dealing with complex network scenarios. Whether working on Windows, Linux, or Mac OS, WireShark provides a compelling solution for users in need of a comprehensive and reliable NetFlow analyzer.
Pros:
- Visual and User-Friendly UI: The GUI makes packet inspection easier to navigate, even for users with limited experience.
- Community-Driven Enhancements: Open-source nature ensures regular updates and access to a broad knowledge base.
- Great for Learning: Widely used in academic and training settings to understand how network protocols work.
- Comprehensive Data Export Options: Allows exporting of captured data for external analysis or reporting.
Cons:
- Higher Learning Curve: Can be overwhelming for beginners due to its technical depth and protocol knowledge required.
- Not Ideal for Real-Time Monitoring: Designed more for in-depth analysis than for live, ongoing monitoring on busy networks.
WireShark is a well known tool because it offers one of the most compelling free network analyzers on the market. Whether you’re working within an SME or a larger organization, this tool has more than enough power to sustain even the heaviest NetFlow workload. WireShark is available for Windows, Linux, and Mac OS. Download WireShark for free here.
9. FlowScan
FlowScan is one of the most basic NetFlow Analyzers on this list. What it lacks in complexity it makes up for in its one-track approach to network monitoring. FlowScan produces real-time graphs of your network activity. While these aren’t as polished as a tool from a company like ManageEngine, they are clear enough to generate a realistic appraisal of live activity.
Key Features:
- Real-Time Traffic Analysis: Continuously monitors and displays network flow data, helping admins detect issues as they happen.
- Modular Reporting Structure: Lets you tailor flow reports to your specific needs using a customizable framework.
- Integration with External Tools: Works seamlessly with various third-party components for flow collection and visualization.
- Visualization Capabilities: Converts raw network data into web-friendly charts and graphs for easy interpretation.
- Open-Source Availability: Fully free to use and modify, allowing for community-driven improvements and custom builds.
Why do we recommend it?
FlowScan, despite its simplicity, is recommended for its straightforward and focused approach to network monitoring. As one of the more basic NetFlow Analyzers, FlowScan excels in producing real-time graphs of network activity. While it may lack the sophistication of tools from larger companies, its clear and concise graphs provide a realistic assessment of live network activity. FlowScan’s uncomplicated design makes it accessible for users seeking a tool with a singular focus on monitoring network activity.
Two main components make up FlowScan: CampusIO and SubNetIO. CampusIO is referred to as a ‘report module’ that interacts with the raw flow data and pushes it into a database with packet, byte, and flow counters. SubNetIO effectively does the same thing as CampusIO but adds per-subnet statistics on applications to the mix as well.
Who is it recommended for?
FlowScan is recommended for users who prioritize simplicity and a singular focus on network monitoring. Its clear real-time graphs make it suitable for those who value straightforward insights into network activity without the complexities of more advanced tools. While it may not offer the extensive features of some competitors, FlowScan is a practical choice for individuals or organizations looking for a basic yet effective NetFlow Analyzer.
Pros:
- Detailed Network Insights: Offers comprehensive visibility into network flow patterns, which helps with diagnostics and optimization.
- Cost-Efficient Option: Open-source nature makes it a highly affordable choice for organizations with tight budgets.
- Flexible Reporting Tools: Users can build specific reports to focus on particular traffic types or trends.
- Strong Community Backing: Benefits from open-source support with contributions, updates, and fixes from users worldwide.
Cons:
- Scalability Challenges: May struggle under the load of very large networks or high-speed environments.
- Heavy on Dependencies: Requires managing multiple moving parts and tools, which can complicate maintenance.
FlowScan can be downloaded from here.
10. sFlow Toolkit
sFlow Toolkit has to be one of the top NetFlow analyzers for analyzing sFlow data. This tool is based around a command-line interface and lets users create scripts to customize their traffic flow analysis. SFlow is compatible with tools such as tcpdump and ntop, which helps increase its reach.
Key Features:
- Command-Line Utilities: Includes a robust set of CLI tools for analyzing and interpreting sFlow data.
- Third-Party Tool Integration: Works well with apps like tcpdump, Snort, and ntop for more advanced traffic inspection.
- NetFlow Conversion: Converts sFlow data into NetFlow format to support broader compatibility with other systems.
- Scriptable Output: Outputs plain text data that can be easily integrated into custom scripts or reports.
- Free and Open Source: No licensing fees, with full access to the source code for modification or improvement.
Why do we recommend it?
sFlow Toolkit’s strength lies in its command-line interface, offering users the ability to create scripts for customized traffic flow analysis. sFlow Toolkit is recommended as one of the top NetFlow analyzers specifically designed for analyzing sFlow data. The tool’s compatibility with widely-used tools such as tcpdump and ntop enhances its versatility, extending its reach in network analysis.
For those experienced with command-line interfaces, sFlow Toolkit is a competent tool. For example, entering the command sflowtool -t | tcpdump -r launches a decoded packet trace. You can then filter these packets using tcpdump.
Who is it recommended for?
sFlow Toolkit is recommended for users with experience in command-line interfaces who seek a specialized tool for in-depth analysis of sFlow data. Its competency in analyzing sFlows makes it valuable for users looking to focus on specific aspects of network traffic. While it excels in sFlow analysis, it is best utilized as part of a broader network analysis strategy, complementing other tools rather than serving as a comprehensive solution.
Pros:
- Comprehensive Traffic Analysis: Supports deep dives into network activity using familiar and powerful analysis tools.
- Great Format Flexibility: Can bridge sFlow to NetFlow, expanding the number of platforms you can use it with.
- No Licensing Costs: Fully open-source, making it ideal for cost-sensitive environments or labs.
- Customizable Output: Easily integrates with other tools or automation pipelines through scriptable outputs.
Cons:
- No GUI Interface: Only available via the command line, which could be a barrier for users preferring a visual interface.
- Requires Technical Knowledge: Best suited for users comfortable with scripting and terminal-based workflows.
- Limited User Support: Sparse official documentation and fewer community resources can make troubleshooting more difficult.
While sFlow toolkit is a very useful platform, it is best used as part of a wider network analysis strategy rather than an overarching tool. It is good at analyzing sFlows but not much else. If you’re interested in downloading sFlow Toolkit, click here.
11. Colasoft Capsa
Finally, we have Colasoft Capsa. Capsa is a platform aimed at medium-sized networks that allows the user to conduct TCP flow analysis, network protocol analysis, and VOIP analysis. This is truly a network monitoring tool for diverse and dynamic IT environments. Capsa supports over 300 protocols, making it one of the most versatile tools on this list.
Key Features:
- Real-Time Packet Capture: Captures and displays live network data for immediate troubleshooting and analysis.
- Deep Protocol Support: Analyzes traffic from over 500 protocols, making it useful across a wide range of networks.
- Bandwidth Monitoring: Tracks how bandwidth is being used and highlights heavy users and applications.
- Advanced Packet Decoding: Offers detailed views of packet contents in multiple formats like Hex and ASCII.
- Network Topology Mapping: Visually maps out all network connections to show communication paths and traffic flow.
Why do we recommend it?
Colasoft Capsa is recommended for its versatility in network monitoring, offering TCP flow analysis, network protocol analysis, and VOIP analysis. With support for over 300 protocols, Capsa stands out as one of the most versatile tools on the list. Its robust security features, including the detection of suspicious activities like external TCP port scanning or DDoS attacks, contribute to its appeal.
One of the biggest advantages of Capsa is its security features. Capsa can detect when suspicious activity occurs on your network. For example, if it flags external TCP port scanning or a DDoS attack, you will be notified. It also monitors network usage traffic in real-time so you can see exactly what’s going on. You can also set notifications to be sent straight to your email so you know when to take action.
Who is it recommended for?
Colasoft Capsa is recommended for users managing medium-sized networks in diverse and dynamic IT environments. Its broad protocol support makes it suitable for various network scenarios. The platform’s security features make it particularly valuable for those prioritizing network security, with the ability to detect and notify users about suspicious activities in real-time. Capsa’s combination of security and analysis makes it stand out for users seeking a comprehensive solution.
Pros:
- Easy to Use Interface: Clean, intuitive layout makes it accessible for beginners while offering power for advanced users.
- Complete Network Oversight: Provides full visibility into traffic flow, making it easier to pinpoint slowdowns or security issues.
- Built-in Diagnostic Engine: Automatically identifies network problems and recommends fixes for faster resolution.
Cons:
- Limited Wi-Fi Capabilities: Not as strong when analyzing wireless network traffic compared to wired.
- Windows Only: Only available for Windows, which limits use for Mac or Linux-based teams.
- Can Get Pricey: Full-featured versions come with a high cost, which might not suit smaller budgets.
Capsa is truly a platform designed for those in need of versatility. The user interface is quite robust, but this isn’t the platform’s main appeal. Capsa’s combination of security and analysis is really what makes it stand out. Colasoft Capsa can be downloaded from here.
NetFlow data structures
The Cisco NetFlow system is the industry standard for network traffic measurement. Many other manufacturers implement NetFlow on their devices and the other traffic messaging systems are based on NetFlow procedures. So the way this standard structures data is significant.
NetFlow reports on traffic in both directions on network devices. For incoming network traffic it tracks:
- IP-to-IP packets
- IP-to-MPLS (Multiprotocol Label Switching) packets
- Frame Relay-terminated packets
- ATM-terminated packets
For outgoing traffic, NetFlow records:
- IP-to-IP packet
- MPLS-to-IP packets
Each traffic flow is identified by seven key fields. This means that all data collected by NetFlow can be sorted, filtered, or grouped by any of these attributes :
- Source IP address
- Destination IP address
- Source port number
- Destination port number
- Layer 3 protocol type
- Type of service (ToS)
- Input logical interface
Although many network devices have NetFlow capability, you will need to check on that status for each of your network devices. Some manufacturers shop their NetFlow-capable devices with the messaging protocol disabled, so you will have to visit each device on your network and make sure that it has NetFlow messaging turned on when you first install your NetFlow analyzer.
