8 Best NetFlow Analyzers and Collectors in 2023: Deep Dive

In today's complex networks, understanding traffic flow is crucial for maintaining performance, security, and efficient resource allocation. NetFlow, a network protocol developed by Cisco, provides invaluable insights into your network's IP traffic. By analyzing NetFlow data, you can gain a comprehensive view of traffic patterns and volumes, enabling you to troubleshoot issues, optimize bandwidth usage, and identify security threats.

This article delves into the world of NetFlow, explaining its functionality, comparing it to alternative protocols like sFlow, and showcasing the best NetFlow analyzers and collectors available in 2023. We'll explore both paid and open-source solutions to help you choose the right tool for your organization's needs.

What is NetFlow?

NetFlow is a powerful network protocol designed to collect information about IP traffic and monitor network activity. Unlike other protocols, NetFlow excels at providing specific insights into application flows. Think of it as a surveillance system for your network, carefully observing and recording the movement of data packets. This data offers network administrators critical insights into network behavior related to compliance, security vulnerabilities, and application usage.

By implementing a network performance monitor with NetFlow reporting capabilities, you can achieve highly specific troubleshooting and informed capacity planning. In essence, NetFlow empowers you to:

• Identify bandwidth hogs: Pinpoint applications consuming excessive bandwidth.
• Troubleshoot network issues: Expedite the resolution of performance bottlenecks.
• Detect unauthorized traffic: Uncover applications causing unexpected WAN traffic.
• Enhance security: Work with tools like Cisco CS-Mars to identify anomalies and worms.
• Validate Quality of Service (QoS): Ensure optimal bandwidth allocation for critical applications.

NetFlow is now in its ninth version, with Flexible NetFlow and IPFIX extensions available for advanced functionality.

How Does NetFlow Analysis Work?

NetFlow operates by examining IP flows, which are sequences of packets connecting a source and destination. When a packet passes through a router or switch, it is analyzed for specific IP packet attributes. These attributes serve as identifiers to determine if a packet is distinct or similar enough to be grouped with others. NetFlow utilizes seven key IP attributes:

• IP destination address
• IP source address
• Layer 3 protocol type
• Source port
• Destination port
• Class of Service
• Route or switch interface

NetFlow consolidates the data extracted from IP traffic, grouping packets based on these criteria. It then tallies the bytes and packets within each flow before exporting them to a NetFlow collector.

NetFlow analysis relies on three core components:

• Exporters: Routers with NetFlow enabled generate reports.
• Collectors: Process and compress the data received.
• Analyzers: Perform traffic analysis and present the findings in a user-friendly format. These tools can come as different pieces of hardware, or can be software-based.

NetFlow vs. sFlow: Key Differences

While both NetFlow and sFlow are concerned with network traffic, they differ significantly in their approach:

• Methodology: NetFlow uses templates to define data structures, while sFlow employs packet sampling.
• Focus: NetFlow tracks IP flows, while sFlow focuses on sampling packets.

Here's a breakdown of the major distinctions:

• Scalability: sFlow's sampling method generally offers better scalability for high-traffic networks. However, NetFlow with Sampled NetFlow extension can achieve similar scalability.
• Performance: NetFlow's flow cache can impact performance at high volumes, while sFlow minimizes device resource usage.
• Coverage: While NetFlow primarily focuses on IP (Layer 3), sFlow covers Layers 2 through 7, providing broader visibility.
• Latency: NetFlow's flow export mechanisms can introduce higher latency compared to sFlow's real-time sampling.

The choice between NetFlow and sFlow depends on your network's specific requirements, balancing accuracy, scalability, and performance needs.

8 Best NetFlow Analyzer Software

When your network grows making it difficult to isolate problems, a NetFlow analyzer can give you a comprehensive view of your entire network.

Here are eight of the best NetFlow analyzers available:

1. SolarWinds NetFlow Traffic Analyzer (NTA): This is a top recommendation because it combines flow and Class-Based Quality of Service (CBQoS) data to provide bandwidth usage. It also has customizable traffic reports and a user-friendly PerfStack™ dashboard. Try NTA free for 30 days. For enhanced insights, consider using it with SolarWinds Network Performance Monitor (NPM).
2. SolarWinds Engineer’s Toolset (ETS): ETS provides a collection of more than 60 tools for network needs. The tools include NetFlow monitoring, network monitoring, auto discovery, and security. A suite of specialized tools include NetFlow Real-Time Tool, NetFlow Configurator Tool, and WAN Killer Network Traffic Generator. Try Engineer's Toolset free for 14 days.
3. ManageEngine NetFlow Analyzer: This analyzer supports technologies like IPFIX, NetStream, and J-Flow, alongside NetFlow. Includes reports to compare network performance over time and tools for detecting external and internal security threats.
4. Paessler PRTG Network Monitor: This monitor monitors network devices and bandwidth usage. It has automatic device discovery and provides the health of your devices through a unified platform through a tree-structure interface.
5. Kentik Detect: This SaaS solution collects data and brings data types into a unified view and customizable web-based interface, giving you a wide variety of ways to look at your data. The Data Explore helps you explore your network activity by breaking traffic data down into tables and graphs.
6. Nagios: Nagios Core is the free, open-source version, while Nagios XI comes with built-in tech support and features. A reputation for being reliable and powerful comes with potential complex configurations.
7. Wireshark: This versatile open-source tool that extends its capabilities to NetFlow analysis. Wireshark monitors wifi, ethernet, bluetooth, VLAN, and WAN. Capture filters enable you to block out certain traffic based on size alone, while display filters break down traffic data you’ve recorded in the past.
8. nProbe and ntopng: ntopng is a traffic analysis solution that captures packets to monitor data flow and relies on an open-source NetFlow collector called nProbe. It also sorts flow according to IP address, protocol, and throughput. The Community version is free, whereas the Professional and enterprise versions can be a bit pricey.

DIY NetFlow Analyzer Solutions

For those who prefer a customized approach, DIY NetFlow analyzer solutions offer flexibility and control. Tools like Splunk, Elastic Stack, and Grafana can be leveraged to build a traffic analysis system tailored to your specific needs. However, the success of this approach hinges your network size, expertise, and willingness to invest the time required.

Determining the Best NetFlow Analyzer for Your Organization

Selecting the right NetFlow analyzer involves careful consideration of your organization's unique requirements:

• Network size and complexity: Larger, more complex networks may benefit from comprehensive paid solutions.
• Plans for network growth and expansion: Choose a scalable solution that can accommodate future needs.
• In-house expertise: Open-source solutions require technical proficiency and a willingness to troubleshoot.

While open-source tools offer flexibility and cost savings, paid software provides the advantage of dedicated support and out-of-the-box functionality. If you seek a dedicated NetFlow monitoring solution, SolarWinds NetFlow Traffic Analyzer. For comprehensive network monitoring alongside NetFlow analysis, consider SolarWinds Engineer's Toolset.