Best open source network monitoring tools | How to manage your professional network

NetXMS offers an enterprise-grade open source network management and monitoring programme with a simple user interface on Windows and Linux. 

NetXMS provides distributed network monitoring, automated network discovery and detailed reporting for all layers of your IT infrastructure, with a relatively simple installation process.

Plus, the server footprints and agents are pretty lightweight for such a comprehensive product.

Aimed at the enterprise, Pandora FMS offers a sleek and uncluttered user experience with an easy-to-read quick insight tool providing important network stats such as the status of the network, open alarms, the number of agents deployed and a list of any recent tasks being performed.

Pandora FMS can perform network diagnostics without external access, meaning that users could receive a faster response to any network issues. In fact, Pandora FMS says that its monitoring response rate is around 10 seconds for both agent modalities.

Initially released in 2001, Cacti is an open source web-based network monitoring and graphing tool designed for data-logging. It can be used to show network data over time, such as CPU load or bandwidth utilisation.

Cacti is a front end application to RRDtool, an open source database tool for storing data that changes over time, using SNMP as its default collection method, but if you prefer local Perl of PHP scripts, you can used those as well.

Its latest version 0.8.8h was released in May 2016 with key features including unlimited graph item, auto-padding support for graphs, graph data manipulation, custom data-gathering scripts, built-in SNMP support, graph templates, data source templates, host templates and user-based management.

GroundWork Monitor Core is a platform for monitoring networks, applications and cloud computing usage. The open source version includes a license to monitor up to 50 devices and community-based support, and there is also a business edition of the software.

In terms of its network managing capabilities, GroundWork offers auto-discovery and maintenance of network and devices, topology, alarm control, data collection via API, SNMP, IPMI and support for OpenDaylight SDNs.

GroundWork also offers storage management, supporting a large range of enterprise vendors such as NetApp and EMC along with data collection from disk, block or object storage and storage slowdowns and outages visuals.

Due to GroundWork's one-stop-shop approach to network management, this sort of suite might suit larger businesses and enterprises looking for an established brand rather than a developer-focused tool like Big Brother or Big Sister.

Hyperic, from VMware is intended for monitoring custom web applications and their performance across physical, virtual and cloud environments. It works across application servers, web servers, databases, operating systems, hypervisors, messaging servers and directory servers.

Hyperic provides infrastructure and OS monitoring, detailed reporting, application and middleware monitoring, alerts and remediation workflows and a universally-extensible API. 

This network monitoring tool offers an enterprise version that improves on the alerting function and is better able to create baselines.

Linux-based, Observium is an auto-discovery network monitoring tool. According to the site, it's "professionally developed and maintained by a team of experienced network engineers and systems administrators, Observium is a platform designed and built by its users."

Observium offers both a community edition and a professional edition and uses RRDTool for buffer storage and graphing capabilities with an easy to use dashboard and reporting features. However, it does lack report exporting which could be an issue for some businesses. 

Community users will benefit from full auto-discovery of supported devices and metrics, network-mapping through discovery protocols, automatic recognition of hundreds of devices and six-monthly releases. 

While users of the professional edition will receive all community features plus real-time software updates and fixes, rule-based automatic grouping, threshold and state alerting system and traffic accounting system.

Described as an enterprise-class monitoring tool, Zabbix offers real-time monitoring, auto-discovery, mapping and scalability from data collected from servers, virtual machines and network devices.

Zabbix's enterprise monitoring software provides users with built-in Java application server monitoring, hardware monitoring, VMware monitoring and CPU, memory, network, disk space performance monitoring. 

This network monitoring tool offers enterprise-level software able to perform 3,000,000 checks per minute, with added security and data centre monitoring available. 

Nagios is an open source software tool for monitoring IT infrastructure and viewing current status, historical logs and basic reports. Nagios users can monitor system metrics, network protocols, applications, servers, network infrastructure and receive failures alerts.

Nagios offers three types of network management tools, Nagios XL, Nagios log server and Nagios network analyser with Nagios XL being the most fitting for network monitoring (although the others do offer network monitoring support). 

Nagios XL offers enterprise-level network monitoring, providing users with bandwidth reports, heartbeat monitoring, custom action URL, email reports and remote machine monitoring. The enterprise upgrade providing web-based server console access, business process monitoring, audit logging and automated decommissioning as well.

Designed for Unix-like operating systems, NetDisco offers web-based auto-discovery of networked devices via NSMP, creating pictures of networks, designed for moderate to large networks.

This network management tool can be used to locate devices, create an inventory and report on IP address and switch port usage.

NetDisco users can locate a machine on the network by MAC or IP, turn off a switch port, or change the VLAN or PoE status of a port, inventory your network hardware by model, vendor, software and operating system and create detailed pictures of your network

Initially released in 1999, OpenNMS provides event management, service monitoring and performance measurement designed for large to enterprise-level businesses.

Key features enterprise users will benefit from includes external scripts, send alerts to on-call system engineers, extend the Java native notification strategy API, request Tracker (RT) integration, high-level alarms, IPv4 and IPv6 network reachability over ICMP, test statuses, and node inventory information.

It's enterprise service or 'flavour' Meridian offers preconfigured events, notices, data collection, workflows and reports in addition. 

RANCID sounds like a negative name, until you learn that it stands for Really Awesome New Cisco config Differ. That means it monitors a router or other device's configuration and maintains a history of any changes. And also despite the name RANCID supports many vendors' devices, including Juniper routers, HP switches, Redback NASs and many others as well as extending support to Observium.

RANCID supports many vendors' devices, including Juniper routers, HP switches, Redback NASs and many others as well as extending support to Observium.

RANCID offers a variety of network management features including a login to each device in the router table (router.db), run various commands to get the information that will be saved, email any differences from the previous collection to a mail list and commit those changes to the revision control system.

Another network monitoring tool to consider is Xymon (formerly called Hobbit). Xymon monitors servers, applications and networks, offering information about the health of all of those networked components via web pages.

Its site says it was inspired by Big Brother, and like Big Sister, it attempts to address perceived shortcomings of Big Brother BTF, such as performance. Xymon is also intended to be easier to deploy and is free.

Big Brother was created in the mid-1990s to monitor networked systems and was later acquired by Quest Software, which was subsequently purchased by Dell in 2012.

Many other network monitoring tools has been modelled on Big Brother so it's a good place to start for a vast and detailed forum and helpful developer community.  

Alongside an open source version available for students and non-commercial, a business version, called Big Brother Professional Edition, is also available.

Big Sister creator Thomas Aeby said he was impressed by Big Brother's network monitoring but wanted to change to improve the performance, reduce the number of alarms when something goes down and make other enhancements.

Big Sister offers network monitoring, a node director, doxygen filter and a web application framework, working as part of Unix derivatives and Microsoft Windows operating systems. 

Big Sister can be useful for IT admins wanting to monitor networked systems, be notified when systems are becoming critical, generate a history of status changes and log and display a variety of system performance data.