Best Free Network Monitoring Software

By on January 22, 2020

The good thing about living in a world with so many network monitoring software options is IT administrators can be selective. The bad thing is sometimes there are too many options out there, and it can be hard to know which one is right for you. That’s why we’re breaking down the best free network monitoring software on the market right now.

We highly recommend reading through the whole list to get a good overview of your options, but we understand if you’re in a hurry, so we’ll cut to the chase. While some admins swear by free network monitoring tools, we think most businesses should invest in paid tools when possible—open-source tools can be a hassle and free tools are typically limited in scope. But if you’re set on using free options, don’t worry—we have an extensive list of the top free network monitoring options below.

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Why Do I Need Network Monitoring Software?
Best Open-Source and Free Network Monitoring Tools
Other Useful Tools for Network Monitoring
Additional Free Networking Monitoring Software
How to Choose the Best Monitoring Software

Why Do I Need Network Monitoring Software?

It bears repeating—routine networking monitoring is the best way to ensure your network is in tip-top shape. To build a network, you must set up an architecture, sketch out the design, and choose a hardware infrastructure to meet your requirements. Many organizations rely on their networks to generate a large percentage of their annual revenue, so it’s critically important you both keep your network running smoothly and have the right tools in your repertoire to do so.

By giving you a comprehensive overview of your entire computing environment, network monitoring software helps you keep track of your systems, troubleshoot effectively, and head off-network performance issues before they occur.

If you’re looking for a comprehensive network monitoring solution designed to meet your budget, our pick is SolarWinds® Network Performance Monitor (NPM). This network monitoring tool is easy to install, easy to use, scalable, and can handle all your monitoring and reporting needs right out of the box.

SolarWinds® Network Performance Monitor (NPM)

NPM provides a centralized view of network performance and is built to enhance and deepen the insights you may be getting from using free tools with more comprehensive monitoring capabilities.

Best Open-Source and Free Network Monitoring Tools

Open-source and free tools can provide some excellent capabilities. Still, this doesn’t mean they’re right for everyone or every business. For example, open-source tools are often labor-intensive to set up. Custom fixes often aren’t available until you spend a significant amount of time developing and maintaining the system yourself. You’re on your own if you encounter any issues because open-source tools don’t come with embedded tech support—instead, you have to filter through blogs and community chat rooms for assistance. In addition, there are security risks—when you use an open-source or free tool, you run the risk of downloading buggy software.

All of this isn’t meant to persuade you from downloading and trying out open-source or free network monitoring tools. A lot of them are great. We just want you to know what you’re getting into before you decide to take on using these tools. If you choose to go this route, here are the best open-source or free network monitoring tools currently available on the market today:

  1. ipMonitor

SolarWinds is known for putting out some high-quality free network monitoring tools, and ipMonitor® is no exception. It’s a great option for IT administrators responsible for managing small environments and looking for a centralized monitoring system.


With ipMonitor, all your bases are covered—monitoring, alerting, automated reporting, and automated remediation actions. If you’re looking for something with a little more power, SolarWinds also offers a paid version of ipMonitor with a few more features and capable of handling larger networks.

  1. Nagios Core
Nagios Core

Nagios is a well-known name in the tech community and its open-source products are incredibly popular. Users prefer Nagios because it has a robust online development community and its products can support external plugins, which you can use to configure Nagios Core to your individual needs.

You can build external plugins in the form of executable files or Perl and shell scripts to, for example, collect and monitor data pulled from every hardware and software system involved in your network. Other plugs allow you to:

  • Improve your graphical user interface (GUI)
  • Supplement some of the technical limitations of Core (Nagios XL is the extended, paid version)
  • Enable numerous support features like auto-discovery, enhanced graphing, notification escalation, and much more.

Nagios Core is my top pick when it comes to open-source free network monitoring software—you’ll be in good hands.

  1. Zabbix

Zabbix is almost as ubiquitous as Nagios but it’s down a few pegs on our list because it’s more difficult to set up than we’d like. However, once you get the hang of it, it’s easier to manage thanks to a clean and simple GUI.

Zabbix has agentless monitoring capabilities to help you monitor technologies like SNMP (Simple Network Management Protocol), ICMP (Internet Control Management Protocol), Telnet, and SSH. Have agent-based systems or databases? No problem. Zabbix can handle them all—Linux, Windows OS, Solaris, MySQL, PostgreSQL, SQLite, Oracle, and IBM DB2. You can also monitor your VMware environment by customizing any scripting or programming language.

Zabbix is a good choice if you want wide-ranging system coverage and an easy-to-use dashboard.

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  1. Cacti

Cacti is another great network monitoring tool and has withstood the test of time. This name shows up on top tool lists again and again because you can collect data from virtually anything on your network, from routing systems to firewalls. Once you’ve done that, Cacti makes it easier for you to transform the information into complex graphs. We’re willing to bet if you have a device, the developers over at Cacti have built a monitoring template for it.

Cacti supports SNMP polling for a wide range of devices, covering a large portion of your network monitoring needs. If you’re looking for a little more precision or power, you can extend Cacti’s functionalities to include scripts, queries for SQL monitoring, and commands for all-purpose data collection. Afterward, you can save these parameters and use them as templates when you poll other devices with similar characteristics.

Cacti is powered by RRDTool, a logging and graphing tool to create graphs from stored datasets—it’s also open-source. This feature could be enticing for IT administrators in large enterprises because RRDTool essentially has an unlimited supply of storage space. You can store collected data in RRDTool forever and you’re only limited by the size of your own storage. You can also add multiple users and set up access for them without editing individual permissions—another useful feature for large IT departments.

  1. ntopng

ntopng, the open-source network monitoring tool formerly known as ntop, captures packets using libpcap and uses the data to report on network traffic. Once you install ntopng onto the server you want to monitor, use port mirroring or a network tap to filter the data packets into ntopng for analysis. This tool can:

  • Keep up with network traffic moving at 10G speeds
  • Sort your traffic based on numerous factors like IP, port, and protocol
  • Generate customized reports based on usage
  • Collect IP addresses, volume, and byte information for each transaction
  • Show you the “top talkers”
  • Report on AS information

This level of clarity and visibility makes capacity planning a breeze and helps you pinpoint the users and applications on your network eating up bandwidth. You can also combine ntopng with other network monitoring software systems like Nagios for a full reporting, monitoring, and packet tracking experience.

The paid version of this tool, called ntopng pro, comes with more features. But if all you’re looking to do is track packets and gain actionable insights into network behavior, the free tool will do just fine. There are some technical limitations with ntopng but those cons are outweighed by one major pro: gapless network traffic visibility.

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  1. Spiceworks

Spiceworks comes with a bunch of different free IT management tools including help desk workflow, inventory management, standard network monitoring, and even cloud monitoring. It monitors your network using agentless techniques like WMI (Windows Management Instrumentation) and SNMP and uses the data gained to offer insights into many common network performance issues. You can also customize your own notifications and alerts right there in the app.

Disclaimer: Spiceworks is free because it makes its money running ads. This won’t affect your network monitoring abilities at all, but it might affect your experience using the app if you don’t like seeing ads.

  1. Observium Community
Observium Community

Observium, like many of the latest open-source free network monitoring tools, has a set of free essential features you can upgrade if you pay for additional options, plugins, or extensions.

Be careful when considering this tool. Even though the free version can monitor an unlimited number of devices, Observium is only meant for home use, which means it cannot scale past a single server. If you’re looking for a tool capable of handling a medium to a large corporate network, you might want to pass on this product.

The free version boasts a six-month patch and update cycle, which is good, but if you want to patch your system more often, you’ll have to pay for it. Last caveat: the free version doesn’t come with alerting capabilities.

All these disclaimers aside, we included Observium Community on this list because it’s good for beginners or small home business users who want something a little minimalist but still functional. You can still get a full auto-discovery of all your network devices and the usual metrics, but don’t expect any bells and whistles.

  1. Icinga

Icinga is backward-compatible with Nagios scripts, built on top of MySQL and PostgreSQL, and primarily focused on overall network monitoring.

Nagios developers first created Icinga in 2009, so you know you’re getting high-quality free network monitoring software with this tool. In ten years the Icinga team has critically expanded its functionality and usability, so if you’ve used this tool in the past and stopped using it for whatever reason, it might be time to take a second look.

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Other Useful Tools for Network Monitoring

These next two tools are our Honorable Mentions. They’re not quite full-fledged network monitoring solutions, but they’re still useful enough to be included for good measure.

  1. Nmap

Network administrators love Nmap for its speed and scalability. Nmap scans an entire network full of machines as easily as it scans a single host. This tool specializes in locating hosts on your network, so they can be analyzed and input onto a network map. You can quickly find out about any device’s operating system, services, port status, MAC address, reverse DNS name, and much more.

  1. Wireshark

Wireshark is a big name in the open-source community. This packet analyzer, like ntopng, uses libpcap or winpcap (the Windows equivalent) to capture packets moving across your network. Users love Wireshark because once you’re done capturing traffic, you can analyze it according to nuanced metrics like packet type, packet source, packet destination, and more. Wireshark’s filtering capabilities are unmatched.

That’s not all. Wireshark can also analyze VoIP calls, compile high-quality graphs based on all traffic collected, decrypt protocols (if you’re an advanced user), export the output, and much more. Even though Wireshark won’t technically monitor your network, being able to drill down on packet usage at such a microscopic level makes it a great addition to your toolkit and a worthy supplement to your other network monitoring software.

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Additional Free Networking Monitoring Software

In contrast to some of the more general network monitoring tools, these next selections can help support your networking monitoring efforts but are purpose-built to track only one or two elements of network performance. Adding a few of these free network monitoring tools to your toolbox can help provide a more in-depth picture of specific network issues. If the other free networking monitoring tools mentioned earlier are the ice cream, these free tools are the sprinkles (or insert your favorite ice cream topping here) on top.

  1. Real-Time Bandwidth Monitor

When you’re monitoring a network, it helps to ask the right questions. Question one: is bandwidth usage up? Question two: how much bandwidth usage is being eaten up by certain applications? Bandwidth Monitor is solely devoted to bandwidth concerns, so you can dig deep and tackle those preliminary questions before you get into the real issues.

Real-Time Bandwidth Monitor
  1. Response Time Viewer For Wireshark

We like Wireshark for its flexibility and utility. We didn’t include “simplicity” because Wireshark can be hard to learn and configure, especially if you’re inexperienced. Response Time Viewer helps you navigate Wireshark by breaking down its most vital statistics and functions clearly and simply. For example, this tool will help you determine if a slowdown is being caused by the network (three-way handshake) or an errant application or two (time-to-first-byte). This may seem like a small distinction to make, but it can make your troubleshooting quicker, more precise, and more accurate.

Response Time Viewer for Wireshark
  1. Traceroute NG

Ping is good, but Traceroute NG is built to be better. There are many routes a packet can take to get to its destination at any given time, but this information doesn’t do you any good. What you really need to know is how all the packets on your network are getting across your network at any given time, and Traceroute is excellent at doing this. With this free tool, you can keep an eye on your packets and keep ICMP suppression at bay all at the same time.

Traceroute NG
  1. IP SLA Monitor

IP SLA (Internet Protocol Service Level Agreement) monitoring is a secret weapon for network engineers. Many people overlook it because they think it’s something you only use for VoIP, but IP SLA can also give you valuable information about packet loss, jitter, and MOS—key factors affecting network performance. Use this tool to test remote DHCP servers, check DNS response times from anywhere, and verify vital services like FTP and HTTP are running smoothly.

IP SLA Monitor

How to Choose the Best Monitoring Software

Between commercial products, free tools, and open-source tools, how do you choose the best free network monitoring software? There’s no shortage of products designed to make our jobs as network and IT professionals easier. Although these free tools aren’t completely “one-and-done,” we think everyone can find something fitting their needs on this list. Check out the free tools above to get started and to better understand what kind of functions you prefer for monitoring your network. Or if you’d like to go straight for an enterprise-grade tool, look at SolarWinds NPM—you can try NPM free for 30 days.

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