That being said, there are a few open source network monitoring tools that can give close source tools their run for the money. In case you are wondering, here are some of the best open source network monitors tools that are also free.

Open Source Network Monitoring Tools

1. Cacti

Cacti is an industry standard RRD (Round Robin Database) and data logging tool that shows beautiful and detailed graphs. Cacti have a built-in MRTG (Multi Router Traffic Graphing) module that can track and measure router traffic like process time on a server, lost packets, actual network traffic, etc. One of the biggest benefits of Cacti networking tools is that it can not only track and gather the data but can also represent the data in almost any way you want. This is very useful to compare and manipulate the results as and when needed. Read: How to Boost Your Wi-Fi Network With an Old Router Do keep in mind that to get started with Cacti, you need to have PHP, Apache, and SNMP installed on your system or server. If you want a software that can gather data from different end data points and lets you represent and manipulate the collected data in beautiful and useful graphs, then Cacti is for you.

Platform support: Cacti support Windows and Linux. Download Cacti.

2. Nagios Monitoring

Nagios is one of the popular when it comes to open source network monitoring tools. While Cacti is designed with a focus on data manipulation, Nagios’s main focus is creating statuses and alerts on events based on gathered data. Now, since Nagios has plugin support, you can create graphs based on the gathered data by installing first-party or third-party plugins. Though the user interface of Nagios looks pretty old, it is quite lightweight, reliable, and fast. Compared to other network monitoring tools in this list, Nagios offers greater control but has a pretty steep learning curve, especially for beginners. Nagios comes in two different flavors. i.e. Nagios Core and Nagios XI. The first one is free and open source and the second one is a paid enterprise version. If you are looking for a feature-rich network monitoring tool that has an extensive set of plugins and scripts with great community support, then do give Nagios a try.

Platform support: Nagios supports both Linux and Windows. Download Nagios Monitoring.

3. Icinga

Icinga is a fork of Nagios monitoring tool. Out of the box, Icinga not only looks much better with its responsive web user interface but also has extensive database support and much better scalability. Though Icinga started out just as a fork to Nagios, the developers completely rewrote the Icinga core to increase its responsiveness, reduce complicated setups, and ease of use. Features of Icinga include but not limited to monitoring all the network services and components, even handlers, customizable template-based reports, and plugin support. Just like Cacti, Icinga can create detailed graphs for analysis and data manipulation. Though Icinga still uses text files for configurations, the process is much more improved when compared to Nagios. So, if you like the feature set or how powerful Nagios is but don’t want to deal with complicated setups and dated UI then Icinga is for you.

Platform support: Icinga support Windows and various Linux distributions like Ubuntu, Fedora, Debian, Red Hat, etc. Download Icinga.

4. Zabbix

Zabbix is a very popular and industry-leading network monitoring tool that is mostly used by the big guys like Salesforce, Dell, etc. One of the best things about Zabbix is that it not only has one of the best and easy to use user interface, but it allows you to do almost all the configuration stuff via the web interface. Which simply means that the learning curve is not as steep as Nagios. Additionally, Zabbix supports automatic discovery of the connected network and its components. Keep in mind that Zabbix comes in client and server architecture. Which means that you need to install the Zabbix agent on the client machine to properly monitor its activities. That being said, Zabbix has no problem tracking regular service like HTTP, SSH, FTP, etc., without installing the client. Other features of Zabbix include self-protection against unwanted configuration changes and brute-force attacks, script automation, ability to integrate with other industry management tools like bcfg2 and Puppet. Zabbix is perfect for those who want great user interface and ease of configuration and use.

Platform support: Zabbix is a Linux only software. Download Zabbix.

5. OpenNMS

OpenNMS is mainly designed in an event-driven architecture and supports metric collection in a variety of types like WMI, JSON, SML, HTML, XML, etc. When pre-defined or custom events occur, OpenNMS can send alerts via SMS, email, and a variety of other methods. Just like Zabbix, OpenNMS can automatically discover network, based on the IP list or range set by you. Since OpenNMS has been integrated with JFreeChart, you can create useful graphs for data manipulation, comparison, and analysis. Other features include provisioning, event management, service monitoring, ability to self-clear problems, detailed performance reports and help desk ticketing support. To get started as quickly and efficiently as possible, OpenNMS has detailed documentation and educational video tutorials.

Platform support: OpenNMS support Linux, Windows, and even has support for Docker containers. Download OpenNMS.

6. LibreNMS

LibreNMS is a tad bit similar to Cacti in that it needs the other devices to have SNMP clients or agents installed to work properly. Which means that you can use LibreNMS on almost any router to gather the data as extensively as possible. One of the neat features of LibreNMS is its alerting system. You can configure alerts based on a variety of events and when triggered, it can send notifications to you via different channels like SMS, Slack, Email, etc. The user interface of LibreNMS is pretty straightforward and clutter free. This makes it easy for the beginner to get started easily. Of course, there is detailed documentation of each and every feature, if you ever need help. Features of LibreNMS include automatic network discovery, Android and iOS apps, horizontal scaling, and full API access. Read: Best Free Remote Access Software for Freelancers And Small Business

Platform support: LibreNMS supports Linux and Docker containers. Download LibreNMS.

7. Pandora FMS

Of all the network monitoring tools listed here, Pandora FMS is the most versatile one when it comes to features. While Pandora FMS supports monitoring switches, routers, and any other gateway devices, you can install additional plugins to monitor other systems like Microsoft Exchange server, Tomcat, IIS, etc. Along with network monitoring, Pandora FMS even comes with a built-in remote server management module to help manage devices remotely. Other features of Pandora FMS are network visualization, detailed event management, centralized management options, vertical scaling, automated updates, router bandwidth monitoring, network topology detection, module execution on conditions or events, etc. All in all, if you are looking for a feature-packed network monitoring solution then do give Pandora FMS a try and see how it works for you.

Platform support: Pandora FMS supports Windows, Linux, and Docker containers. Download Pandora FMS. That is all. Do comment below if you think I missed any of your favorite open source network monitoring tool. Also Read: Top 10 Network Monitoring Apps for Android