5 Open Source Network Monitoring Tools

Cacti
Cacti is an open-source web-based monitoring and tracking tool. It is a very high-performance graphical tool for networking monitoring. This application runs on Apache and supported PHP and Mysql database. It facilitates their use by providing customize-able front end Graphical User Interface to the PRDTool, it controls temperatures, bandwidth, and CPU load. Cacti allow their user to determine the data in specific time periods by scheduling. This software has the ability to track fan speeds, power supply, and disk utilization. It provides data collection scripts to their user and can also collect data through SNMP. No need to install the agent on the device. For taking full features advantages of this software need to install SNMP. The installation procedure of this software is very easy, it can also be installed on Window operating system. This software was initially released on September 23, 2001.
License Type: GNU General Public License

Zabbix
Zabbix is an open-source network monitoring tool design for monitoring the performance and availability of IT components. Its source code is publicly open and has the freedom to customize it according to your needs. Installation of Zabbix is very easy and provides a beautiful user interface that comes with an agent and without agent support. It is also used for monitor track, network service, server, and network hardware. It used multiple databases like MYSQL, SQLite, Oracle, PostgreSQL. The front end of this software tool is written in PHP and the back end is written in C language. Zabbix provides different features to their user like it provides distributed monitoring with centralized web administration, High performance, high capacity, secure user authentication, flexible user permissions, Native high-performance agents, and many more. It also supported cross platforms.
License Type: GNU General Public License version 2

Observium
Observium is a free and open-source monitoring tool. It is Linux-based software that provides a web-based monitoring interface. Obervium comes in two editions, a community-based edition, and a professional edition. It supported PRDTool which provides different features like graphing and buffer storage. It collects data by using SNMP and shows it through a web interface. It supports the MYSQL database for storage and used PHP language. The basic goal of Observium development tea is to provide maximum automation, minimum accessibility of information, minimum interaction to their user. For extending features it used RANCID, jpgraph, and GeSHi software. It provides integration support. To enhance features like graphics it can be integrated with Nagios. It provides excellent onboard reporting and a user-friendly graphical user interface. It has been released initially in October 2006.
License Type: Observium License, QPL

Icinga
Icinga is an open source is networking monitoring software tool. The configuration setup of this software is very complex. It provides the module design by using this you can select the core server. You can adds plugins to this software like the graphic and reporting plugin. The basic server you can install simply by running just two commands. A quick start guide is very helpful and also online documentation is written very comprehensively. This software provides facilitation of migration between the two monitoring software. It provides multiple monitoring features like monitoring of network services, monitoring of host resources, monitoring of server components, parallelized service checks, provide a plug-in design that allows users to easily develop their own service checks, etc. Icinga provides advanced graphical web GUI and granular configuration options. It was initially released in May 2009.
License Type: GPL version 2

Ganglia
Ganglia is an open-source scalable network monitoring software tool. It is used for high-performance computing systems like grids and clusters. It allows remote access of their user. You can remotely view live statistics on which machine you want to monitor. It used different techniques like XDR for compact, XML for data representation. It also facilitates the data transport and comprehensive RRDTool for virtualization and data storage. Ganglia is supported cross-platform and it is written in C, Perl, PHP, Python. The new stable version of this software has been released a few days ago on 1 April 2015.
License Type: BSD license