cables connected to an optic ports and UTP Network
Image: asharkyu/Shutterstock

Your network is either constantly under the threat of attack or suffering from bottlenecks caused by misconfigured or compromised systems. Or, if you’ve not already had to go through the nightmare that is a problematic network … you eventually will.

SEE: 5 programming languages network architects should learn (free PDF) (TechRepublic)

One tool that’s instrumental in keeping you apprised of issues is the network monitor. These tools range from the simplistic to the overly complicated, from open-source and free to proprietary and costly. Some network monitors do too little, some too much and some offer the perfect blend of features and ease of use.

I want to offer my five favorite network monitoring tools. You’ll probably find one or more of these winds up in your regular toolkit for network admin duties.


Wireshark database management
Image: Wireshark

When I need to monitor a network, Wireshark is always the first tool I grab. Not only is this tool free to use, but it’s also open-source, incredibly powerful and does a remarkable job of giving you insights into what’s happening within your network. With Wireshark, you can easily analyze both incoming and outgoing traffic to troubleshoot your network. You can capture traffic and view it in real-time or save it for later analysis.

One of the most powerful features of Wireshark is its extensive filtering capabilities. Simply put, if there’s something you’re searching for on your network, Wireshark can help you find it. You can filter on specific ports or protocols and even capture a specific packet and view the entire stream associated with the packet. The second you see unusual activity from within Wireshark, you can act on it to mitigate the issue. This tool is also a very solid option for IT recruiting. You can set up a capture-the-flag challenge to test possible candidates. The one caveat to using Wireshark is the UI does have a bit of a learning curve. It offers a handy three-pane packet browser, but setting up and running a capture does require some skill. Wireshark is free and can be installed on Linux, macOS and Windows.

ManageEngine OpManager

ManageEngine OpManager
Image: ManageEngine

ManageEngine OpManager is a very powerful monitoring tool that does far more than the average monitor. OpManager can keep tabs on servers, networks, virtual servers, storage and nearly all types of network equipment. This take on the network manager can be installed on Linux and Windows and uses a web-based interface for access, so you can install the platform on a centrally located server (either on bare metal in your data center or a third-party cloud host) and access the interface from anywhere.

OpManager includes alarms volume management, monitoring for CPU utilization monitoring and applications, and even offers network policy violation summaries. Although OpManager doesn’t do auto-discover of individual devices, it’s possible to add those devices via SSH authentication and SNMP, so it can take some time to add all of your devices. Once connected to a device (such as a desktop or server), you can view interfaces, active processes, installed software, apps and various monitors. OpManager does, however, do automatic Network discovery (once you input the details of your network), where you can then add those discovered devices to your inventory. It’s a bit of a roundabout way, but once you have everything added, OpManager is a very easy platform to manage.

You’ll also find mobile apps for both Android and iOS. The price of OpManager ranges from $245 for 10 devices up to $11,545 for 250 devices.


Checkmk network monitor
Image: Checkmk

Checkmk isn’t just a network monitor, but a system, application, server, desktop, databases, containers, storage, Internet of Things and cloud service monitor. If you need it monitored, chances are good Checkmk has you covered. You could even consider this the only monitor you need for both infrastructure and applications. Entire hybrid IT infrastructure can be monitored with this tool.

With Checkmk you’ll enjoy dynamic dashboards, visualizations, log and event monitoring. availability and SLA reporting, and notifications/alerts. There are two versions of Checkmk: Raw and Enterprise Free. The RAW edition is an unlimited, open-source version, whereas the  Enterprise Free Edition is targeted toward small environments but limited to one site and 25 hosts. For bigger environments, you might require one of the Enterprise Editions, including the Standard (from $654/year) to the Managed Services edition (from $1,308/year). The feature set depends on the version you go with, but for many organizations, the RAW edition is a perfect place to start. With Checkmk you get auto-discovery and auto-configuration of plugins to save your operators time in the setup.

Nagios Core

Nagios Core network monitor
Image: Nagios

Another open-source, free network monitor, Nagios makes it easy to keep tabs on the system status of all the devices attached to your network. With effective data collection via an easy-to-use web-based interface, Nagios offers advanced visualizations, configuration wizards, snapshots, performance and capacity planning graphs, advanced user management and more. The web interface makes it very easy for your admins to quickly check on network outages and down hosts. You can view by host, service, groups, service groups, and view reports for availability, trends and alerts.

Although the Nagios interface does seem a bit outdated, it makes everything very clear. It only takes a couple of clicks to discover any issues within your network. Nagios offers a clear and concise status that keeps you aware of a device or network status with OK, WARNING or CRITICAL. Nagios also offers easy-to-navigate network maps of all discovered devices. Nagios can be installed on Linux, Windows and VMware.


Zabbix network monitor
Image: Zabbix

Zabbix is our final entry in this list and is another open-source, free monitor. Zabbix is only available for installation on Linux systems, but it does a great job of monitoring network services, network hardware, servers, database systems and appliances. With this platform, you’ll get a comprehensive view of your IT infrastructure that is adaptable to nearly any architecture (including multi-tenant systems). From small networks to massive enterprise landscapes, Zabbix can help your network admins keep tabs on everything happening within your network.

The one strike against Zabbix is that it’s not all that intuitive, which means your admins will have to suffer through a bit of a learning curve to get familiar with the tool. But once up to speed, your admins can use Zabbix as a powerful platform for deep dives into your IT infrastructure. Zabbix has been around for quite some time and should not be overlooked as your go-to networking monitoring software.

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