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Best IT Infrastructure Monitoring Tools and Software Reviewed in 2021

Since no administrator can have eyes everywhere and yet all need to keep an eye on everything, IT infrastructure monitoring tools are a necessity for most of us. Those tools will effectively keep an eye on things and let you know when something needs more attention. One of the best things about these tools is that there are many to choose from. They might all seem very similar but each has some unique feature that will make it particularly well-suited for your specific needs. This is why we’ve scoured the internet for the very best on the market and we are now bringing you our top ten list of the best IT infrastructure monitoring tools.

Before we reveal our top ten products, we’d like to take some time to go over infrastructure monitoring in general. As you’re about to discover, different administrators and different organizations have different needs when it comes to monitoring. We will then discuss the different types of monitoring systems from the most basic to the elaborate ones. And if you’re curious and love to know how things work, we’ll do our best to explain the essentials of how these tools work. Armed with all this knowledge, you’ll be ready to discover our selection of tools and software.

Infrastructure Monitoring

The need for infrastructure monitoring is quite obvious. Networks are getting bigger and bigger and have more components than ever. It is not uncommon for administrators to have to watch over dozens of devices, if not hundreds. This is simply too much for one person to handle. And it is tedious and boring work, exactly the type of work that is usually best left to a machine.

As much as monitoring is necessary, it is also varied. Different types of systems have different requirements. For instance, while one would likely be more interested in bandwidth usage of networking equipment interfaces, it is the CPU and memory loads that would be interesting on a server. This is why there are often different types of monitoring systems for different types of equipment.

RELATED ARTICLE: 12 Best Network Monitoring Software and Tools Reviewed in 2018

Virtualized environments are a special case and have very specific monitoring needs. This is why some monitoring tools specialize in those. We’ve recently reviewed the Best VM Monitoring Tools to Keep a Watchful Eye On Your Virtual Machines.

To address the requirement of the different types of monitoring, some of the available tools can monitor multiple different environments. They either do it through built-in functionality or by using external add-ons or plugins.

Different Types Of Monitoring Systems

No matter what type of equipment you need to monitor, there are different types of monitoring systems each with increasing level of detail. At the most basic level, you have simple up-or-down monitoring tools. Those will just check that devices are up–and typically alert you when one goes down. They won’t check any of the device’s operational parameters and typically use ping tests to verify that devices are responding.

The next level of monitoring will poll devices–or receive pushed data from the devices themselves or from an agent–to get different operational parameters. They’ll typically store those parameters in a database and display them on some form of tabular or graphical dashboard.

The top level of monitoring adds some kind of alerting feature. It can be based on measured or calculated data with either predefined or user-defined alerting thresholds. Some systems also use a built-in knowledge base to trigger alerts based on certain operational parameters or combination of parameters. Since the whole purpose of using monitoring tools is to free administrators from having to constantly watch systems, needless to say that these systems are by far the most popular.

How Do Monitoring Systems Work?

Although this might seem like a pretty simple question, answering it is not. The problem is that there is not one universal way that every monitoring systems use. There are, however, a few methods and protocols that are used by many tools. We’ll try to explain how some of those operate.

At the base of many monitoring tools is the Simple Network Management Protocol, or SNMP. It specifies a communication scheme between a monitoring platform and the monitored device as well as the structure of the monitored data. SNMP monitoring tools connect to monitored devices at regular intervals to read operational parameters. For example, CPU utilization or memory usage gauges can be read through SNMP.

For network equipment monitoring, some counters called bytes in and bytes out can also be read via SNMP. Typical network equipment has a pair of those counters for each network interface. These are not gauges, though. They are counters that indicate how many bytes have been transmitted and received since the last equipment reset. By knowing the polling interval, simple mathematics will allow monitoring system to calculate average bandwidth utilization.

For monitoring servers, other techniques can be used. In the Windows world, the WMI (Windows Management Instrumentation) protocol is typically used to communicate between monitoring systems and monitored servers. Other protocols like WBEM (Web-Based Enterprise Management) or CIM (Common Information Model) are used in a similar way in the non-Windows world.

Many monitoring systems communicate with monitored hosts via a locally-installed agent. Using agents has several advantages. It gives monitoring system developers the best flexibility in defining what information is exchanged and how. And with the agent running locally on the monitored system, it will typically have access to more information than what’s available using standard protocols. Agents have a price, though. They are running on the monitored system and, as such, they consume some of its resources.

Our Top 10 Best IT Infrastructure Monitoring Tools And Software

1. SolarWinds Network Performance Monitor 

SolarWinds’ flagship product is called the Network Performance Monitor, or NPM. It is a complete network monitoring solution. The tool’s primary assets are its simplicity, its scalability, and its customizability. The tool’s GUI is very intuitive and easy to use and learn. It will scale from the smallest network to huge installations with thousands of devices over multiple sites. As for the customizability, it is everywhere: in the dashboard, the views, the reports, the alerts.

SolarWinds NPM Summary

The Network Performance Monitor’s alerting system is among the best. It can either be fully customized to your needs or be used out-of-the-box with minimal configurations. The built-in intelligence of the alerting engine will not send notifications for “unimportant” events in the middle of the night or send hundreds of  “device unreachable” notifications for a device located behind a down router or network switch.

SolarWinds Network Performace Monitor starts at just under $3 000 and goes up according to the number of devices to monitor and the selected optional components. It will only monitor networking devices. If you have servers to monitor as well, you’ll also need the SolarWinds Server and Application Monitor reviewed below. If you’d rather try the product before purchasing it, a free 30-day trial version is available for download from the SolarWinds website.

2. SolarWinds Server And Application Monitor

If, instead of networking equipment, what you need to monitor are servers and their processes, then what you need is the Server and Application Monitor, also from SolarWinds. As you’d guess from its name, it monitors applications as well as the server hosting them. The software can scale from very small networks to large ones with hundreds of servers–physical or virtual–spread over multiple sites. The tool can also monitor cloud-hosted services like those from Amazon Web Services and Microsoft Azure.

SolarWinds Server and Application Monitor - Summary Dashboard

Setting up the tool is easy and the initial configuration is done with the help of an auto-discovery process. It is a two-pass process that will first discover servers, then applications. To speed up the process, a list of applications to look for can be supplied. After the initial setup, the user-friendly GUI makes using the Server and Application Monitor easy. Information can be displayed in a table or graphic format.

Pricing for the SolarWinds Server and Application Monitor Is similar to that of the Network Performance Monitor. And like its cousin, a free 30-day trial version is available for download.


PRTG is an integrated tool that will monitor any system, device, traffic, and application in your IT infrastructure. PRTG is quicker and easier to install than most other network monitoring tools. The publisher claims you could start monitoring within two minutes. PRTG’s auto-discovery system will scan network segments and automatically recognize a wide range of devices and systems. It will then create sensors from predefined device templates.

PRTG Screenshot

The platform also proposes a highly flexible and customizable alerting system. You can get alert notifications pushed to your mobile device when using the free client apps for Android, iOS, and Windows Phone. You can also get them via email or SMS according to your needs.

There’s a free, full-featured version of PRTG which is limited to 100 sensors. There’s also a device-unlimited 30-day trial version. To monitor more than 100 sensors, you’ll need to purchase a license. Price increases with the number of sensors starting at $1 600 for 500 sensors up to $14 500 for unlimited sensors. Note that each monitored parameter–not device–counts as one sensor. For example, monitoring the bandwidth on each port of a 48-port switch will count as 48 sensors.

4. WhatsUp Gold

Once just an up-or-down type of monitoring tool, WhatsUp Gold has evolved into a full-fledged monitoring system with all the bells and whistles. It has, for instance, one of the best alerting systems and can be configured to transmit alerts using a multitude of ways including email and SMS, to name a few.

WhatsUp Gold Screenshot

WhatsUp Gold won’t only monitor devices, it will also monitor selected services and processes. It will, for instance, monitor Exchange and SQL servers, Active Directory, IIS and Apache Web services. And if your organization is using cloud-based equipment, WhatsUp Gold will also monitor AWS or Azure installations.

5. Nagios (Core and XI)

Two versions of Nagios are available. There’s a free open-source version called Nagios core and a commercial product called Nagios XI. Both use the same core–hence the name of the free version–but while the free one relies on community-developed add-ons and plugins for most monitoring tasks, the commercial product includes them.

Nagios XI Dashboard

Nagios an excellent monitoring solution for applications, services, operating systems, network protocols, systems metrics, and network infrastructure. And if that ain’t enough, third-party add-ons let you monitor virtually anything.

Nagios XI is available in Standard and Enterprise editions. The Enterprise Edition has some additional functionality and boasts features to assist in large-scale configuration, forecasting, and scheduled reporting. The standard edition starts at $1 995 while the Enterprise starts at $3 495. A free version of Nagios XI is available but it is limited to monitoring seven devices.

6. ManageEngine OpManager

The ManageEngine OpManager is another all-in-one package that will monitor both your servers’ (physical and virtual) and your network equipment’s vital signs and alert you as soon as something is out of specs. The tool boasts an intuitive user interface that will let you easily find the information you need. An excellent reporting engine is included along with some pre-built reports as well as custom ones. The product’s alerting features are also very complete.

ManageEngine OpManager Dashboard

The ManageEngine OpManager is available in two versions, The Essential edition is intended for small and medium organizations with up to a thousand devices with prices starting at around $700 for 25 devices. For larger organizations, choose the Enterprise edition which can scale up to ten thousand devices. Its price starts at under $20 000 for 500 devices. Like with most similar commercial monitoring tools, a free 30-day trial is also available.

7. OP5 Monitor

OP5 Monitor is an open-source network monitoring tool which is based on a Naemon, a fork of Nagios. It is advertised as “the enterprise-level open-source monitoring solution“. Among its main features, we can mention its fully customizable dashboard where you can choose to only display what’s important to you. It also has excellent scalability, particularly in distributed environments.

OP5 Monitor Screenshot

The alerting features of OP5 Monitor are also very complete. Alerts don’t only trigger notifications, they can also launch event handlers; scripts that can make issues self-healing. The tool integrates easily with other systems–such as ticket management or CRM–and it has a developer-friendly API if you want to extend its functionality

Pricing for the OP5 monitor can be obtained by contacting OP5 directly. Although there is no free trial version available, an online demo available should you want to see the product in action before buying.

8. Zabbix

Zabbix is known to be one of the best free and open-source system monitoring platform. This enterprise-grade system can scale from small to very big networks. Zabbix can monitor networks, both local and cloud-based servers, and the services running on them.

Zabbix Dashboard

Zabbix’s business model is unique. The product is free but ancillary services can be purchased from Zabbix. Among the services you can purchase you’ll find five levels of technical support and a complete certification training program. This is totally optional as community support is also available for free and very good. Finally, its alerting features are excellent and so is its reporting engine.

Zabbix has all you’d expect from an enterprise-grade monitoring tool except the high price tag. The only thing you’ll need to spend to give Zabbix a try is your time.

9. Icinga

Just like our previous pick, Icinga is an open source monitoring platform with a feature set that matches most of the best commercial products. One of the main differences in Icinga is the extensive use of plugins. There are literally thousands of them to perform various monitoring tasks and extend the product’s functionality. And if you have a special need for which there’s no plugin, you can always write one yourself.

Icinga Tactical Overview

Another excellent feature of Icinga is the alerting and notification. You can customize alerts to be triggered by any condition you can think of. And it’s just as flexible on how alerts are transmitted. The product has segmented alerting that allow it to send some alerts to some administrators and other alerts to different ones for the best flexibility.

10. Observium

Observium is another open-source monitoring platform whose main feature is a beautiful, intuitive, and simple yet powerful user interface that shows the health and status of your network. It can monitor most technologies and vendors such as Cisco, Windows, Linux, HP, Juniper, Dell, FreeBSD, Brocade, Netscaler, NetApp. This tool only runs on Linux.

Observium Screenshots

Observium is easy to set up and it almost configures itself, thanks to its auto-discovery feature. Like other products, it might need some tweaks to get it to work exactly as you want. The tool offers user-defined alerting thresholds. Another great feature of Observium is how it integrates with other systems, pulling their information and displaying it on its dashboard.

Observium is available in two versions. There’s Observium Community, the truly free and open source offering which is updated twice a year. There’s also Observium Professional with a few more features and daily updates.


No matter which of our top ten tools you choose, you’ll have an excellent monitoring platform. Although they all are functionally equivalent, they are not identical. The main difference is often the look and feel of the tool’s dashboard, a very subjective matter. Choosing the right monitoring system is a difficult task but nothing stops you from trying a few. Most of them can be installed quickly and easily.


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