The best network monitoring tools: an updated comparison

Let’s talk about economics and jam. About the paradox that, according to the data, offering many flavours generates fewer sales than offering just a few, due to that very human phenomenon known as analysis paralysis. Let’s also talk about IT, which is very similar, because every month new applications emerge shining with the glow of novelty, including network monitoring tools, our topic today. Analysis paralysis is widespread in the industry, but that is fine, because we have done the analysis so that you do not have to suffer the paralysis, comparing the best network monitoring tools currently available.
Keeping up with the landscape is our job for one simple reason: to ensure that Pandora FMS, our own option, remains at the forefront, distinguishing between what shines because of marketing and what stands out through genuine ingenuity.
And no, we are not going to tell you that Pandora FMS is the best network monitoring option for everything and everyone. Such a solution does not exist, and claiming otherwise would not be professional. We are the optimal choice for many organisations, but each of us needs something different when it comes to placing sensors across our network, so that our IT infrastructure does not become a ship travelling through space completely blind.
That is why you will discover which option is best for you to deploy today for network monitoring, whoever you may be: an SME, a large enterprise, an administrator of on-premise or hybrid systems, a professional NOC… In addition, this comparison is updated with the latest findings, removing tools that now belong in a museum, adding those that are essential in any serious evaluation process today, and reviewing the solutions that continue to earn their place.
We also want you to obtain value quickly, so let’s complete a couple of necessary formalities to provide some context before moving straight on to a checklist and a quick comparison table, in case you do not have much time.

When should we implement network monitoring in our organisation?

If you already have a tool and want to replace it, you know exactly why you are here and you can skip straight to the comparison. However, if this is our first evaluation, we should ask ourselves three questions:

• Does the business depend in any way on the availability of my networks?
• Has the number of components in the network grown so much that managing them manually takes up most of our day?
• Is traffic increasing without us knowing whether there are bottlenecks or whether the current capacity can handle it?

If we answered yes to any of the previous questions, I am afraid that we are already late. But there is no need to beat ourselves up about it, as that tends to be the natural state of an IT department.

What are the benefits of network monitoring?

The main one, if we choose wisely, is cost reduction, which will certainly please the people in charge of the money.
With a good tool, we can see the overall picture of our infrastructure, know when we need more hardware and when we are overprovisioned, and detect bottlenecks before they affect the sales director in the middle of a demo.
We also gain greater diagnostic capabilities through historical data that allows us to associate issues with network changes, detect anomalous or malicious traffic, and discuss facts backed by data instead of arguing over intuition.
Monitoring turns “I think it’s the network” into a verifiable fact.

Checklist for choosing the perfect network monitoring tool

On Mount Olympus, Hera entrusted surveillance to Argus, a giant with one hundred eyes that never slept at the same time. That is essentially what we are hiring too, so it is worth checking exactly what kind of eyes it comes with.
The criteria are:

• Ease of deployment. In other words, how long it takes to go from installation to obtaining useful data. Some tools can be productive in an afternoon, while others become a project in themselves.
• Automatic network discovery. The tool should be able to find the elements that make up our network and map its topology on its own. Otherwise, we will be condemned to inventory every asset manually.
• Compatibility with SNMP, WMI, ICMP, NetFlow, or similar technologies. This is the foundation of any serious network monitoring strategy: SNMP polling, trap management, traffic flow analysis… If SNMP support is poor, everything else is irrelevant.
• Alerts. They should be flexible in terms of channels, such as email, messaging, and integrations with monitoring systems, as well as delivery policies, with configurable thresholds and escalations adapted to our specific situation. The alternative is to become the main character in The Boy Who Cried Wolf, overwhelmed by irrelevant alerts that we eventually ignore until the wolf really does appear.
• Dashboards. With panels that can be customised for each profile, because the technician on call does not need to see the same information as management.
• Network maps. With a clear topology view that updates automatically alongside real-time statuses. This allows diagnosis in seconds without relying on manual pings or memory.
• Reports. Exportable, schedulable, and suitable for presentation to any profile within the organisation, including customer SLA compliance, as in the case of an MSP.
• Distributed monitoring. If we manage several sites, customer networks, or remote locations, we need probes or proxies that monitor locally while centralising the overall view in a single point.
• Scalability. We should ask how many devices the solution supports and with what hardware, requesting real-world references. Many tools perform well with 500 nodes but crawl through the mud with 5,000.
• Support for hybrid environments. On-premise data centres, public cloud, virtualisation, and containers should all appear in the same dashboard, because today almost nobody operates a completely homogeneous environment.
• Integrations. Based on an open API and connectors for our ecosystem: ITSM, CMDB, ticketing systems, log collection, or a syslog server to centralise network events.
• Automation. This includes automatic responses to events, configuration deployment, and basic remediation. Every recurring action that is not automated becomes operational debt.
• Total cost of ownership. We should not look only at the licence, because that is the trap hidden in the undergrowth. We must also add hardware, administration hours, training, and the future cost of scaling.
• Learning curve. If only one person understands the tool, that person becomes our single point of failure. And if there is one certainty in IT, it is that the only constant is change, especially changing jobs.
• Technical support. Ideally, the tool should have an active community, decent documentation and, when required, commercial support with an SLA so that we do not have to depend on a forum post from 2012.

It is a long list, I know, but it is worth printing it out and taking it with us to the demo so we can ask questions and tick off each point.
Of course, no tool will score perfectly across every category. The key is knowing which criteria are non-negotiable for our environment and where we can afford to compromise.

Comparison table of network monitoring tools

Now that we have reviewed the first practical cheat sheet, let us take a bird’s-eye view to understand the landscape. This table summarises what each tool is and who it is best suited for.

Tool	Type	Ideal for	Key strength	Main limitation
Nagios	Open source	Technical teams that want full control	Huge plugin ecosystem	Manual and outdated configuration
Zabbix	Open source	Small and medium-sized businesses with technical expertise	Very comprehensive while remaining 100% free	Complex templates and reports
Pandora FMS	Open source / Enterprise	Hybrid infrastructures seeking a single console	All in one: networks, servers, and applications	Smaller community than Nagios or Zabbix
SolarWinds	Commercial / Enterprise	Large enterprises with sufficient budget	Network discovery and maps	Price and module-based licensing
Icinga	Open source	Those looking for a modernised Nagios	API and declarative configuration	The complete stack must be assembled
ManageEngine / OpManager	Commercial	Medium-sized businesses	Balance between price and functionality	Paid add-ons quickly accumulate
Observium	Open source	Stable SNMP networks	Detailed graphs	Advanced features only in the paid edition
PRTG Network Monitor	Commercial	Small and medium-sized businesses in Windows environments	Ease of use	Sensor-based costs when scaling
WhatsUp Gold	Commercial	Windows-based teams	Simple discovery and maps	Limited scalability
OpenNMS	Open source	Operators and large networks	Open source scalability	Steep learning curve
Cacti	Open source	Simple SNMP graphs	Simplicity	Falls short as an NMS
Datadog	SaaS / Cloud native	Cloud environments and DevOps teams	Integrations and data correlation	Difficult-to-predict costs
LogicMonitor	SaaS	Hybrid enterprises and MSPs	Fast agentless deployment	Price and limited customisation
Auvik	SaaS	MSPs and distributed networks	Automatic maps and configuration backups	Primarily focused on networks
Site24x7	SaaS	Small and medium-sized businesses seeking an affordable all-in-one solution	Broad coverage at a low price	Limited network monitoring depth
Checkmk	Open source / Commercial	Fast on-premise deployments	Performance in paid editions and automation	Dense interface
LibreNMS	Open source	Community-driven SNMP networks	Free with an active community	Scaling requires in-house work
Centreon	Open source / Commercial	NOC teams and distributed environments	Mature distributed monitoring	Key features in the paid version
Prometheus + Grafana	Cloud native	Kubernetes and microservices	Industry-standard metrics and dashboards	Not a complete NMS
NinjaOne	MSP/RMM	MSPs and endpoint management	Automation and remote support	Not a pure NMS
Atera	MSP/RMM	Small MSPs	Pricing per technician rather than per device	Basic network monitoring

The best network monitoring tools compared

Flying above the landscape and looking down, as we have just done with the table, is impressive, but it does not reveal the details, and implementing network monitoring is a long-term commitment. So let us return to ground level and examine each option in greater depth.

1. Nagios

Here we encounter what is probably the best-known open-source tool. It has been around since 1999, and its grey beard deserves respect because, for years, Nagios was synonymous with monitoring. It defined the basic features that everyone copied afterwards, and several tools on this list are descendants of its code, including Icinga, Centreon, Checkmk, and Opsview. It is important to distinguish between two elements that are often confused. Nagios Core is the open-source component, the engine on which plugins are built to monitor practically anything, and it is what most people mean when they say “Nagios”. Above it sits Nagios XI, the commercial version, which adds a web interface, configuration wizards, and reports. The following analysis refers to Core. However, its significance today is more historical than technical. Thousands of installations are still running, and the oldest have become puzzles made up of patches, scripts, and custom code, making them difficult to maintain and migrate. For a detailed comparison with current alternatives, see Pandora FMS vs Nagios. Does it have a free version? Yes, Nagios Core. Nagios XI is paid.

Advantages of Nagios

• There are many professionals with Nagios experience.
• With in-depth knowledge, configuring it manually can provide almost superhuman monitoring capabilities for specific use cases.
• Its plugin ecosystem is enormous and can be adapted to almost any requirement.
• Despite the above, the basic configuration is straightforward, but…

Disadvantages of Nagios

• Advanced configuration is complex and requires numerous manual file modifications.
• The graphical interface feels outdated in this filter-obsessed world that increasingly focuses only on appearances, and it also results in mediocre usability.
• Significant learning curve. It is not Vim, but it is not particularly friendly on first contact either.
• Each installation eventually becomes a custom implementation that is difficult to evolve or transfer when the person who built the cathedral leaves.
• Reports are somewhat basic.
• Poor SNMP handling, both for polling and trap management.

2. Zabbix

Zabbix is a project that originated in Latvia in the late 1990s, was released as open source in 2001, and has grown into the open-source benchmark that Nagios once was. In fact, many Nagios users have migrated to these warmer lands. It is 100% open source (the company generates revenue through support and services), offering agent-based and agentless monitoring, templates for hundreds of technologies, and a very active community. Historically, its performance deteriorated in large installations, but recent versions have significantly strengthened this Achilles’ heel through proxies for distributed monitoring and improvements to time-series storage. Even so, the key word is “significantly”. Large-scale deployments and complex environment configurations require considerable technical expertise, making it a powerful option that gives nothing away for free. You can find more details in the Pandora FMS vs Zabbix comparison.

Advantages of Zabbix

• Open-source product with no features hidden behind a licence.
• Large and active community, with templates for almost everything.
• Agent-based monitoring, SNMP, IPMI, and remote checks within the same platform.
• Proxies for distributed monitoring across multiple sites.

Disadvantages of Zabbix

• Support depends on local partners, while direct contact with the manufacturer is very expensive and customer feedback is not particularly positive. If official backing is essential, it is not the best option.
• Creating customised reports and dashboards requires numerous steps and becomes a festival of clicks. In practice, most users create reports through custom integrations, something far too common with Zabbix and one of the reasons why there is so little standardisation.
• In very large installations, performance tuning, including the database, requires an expert administrator.
• SNMP trap handling still has room for improvement.

3. Pandora FMS

The apple of our eye, born from real-world experience and more than twenty years in the field. Pandora FMS is a flexible monitoring platform covering networks, servers, applications, and hybrid environments from a single console. In fact, it does not carry the Nagios legacy inherited by Icinga, Centreon, or Checkmk, because we designed it from scratch. We designed it from scratch in the trenches of everyday IT operations, which allows it to scale to tens of thousands of devices through distributed monitoring with satellite servers. For networks, which is our focus today, it provides automatic topology discovery, SNMP and NetFlow, network maps, flexible alerts, dashboards, reports, and SLA management. It also integrates capabilities that would normally require purchasing a second tool: agent-based and agentless server monitoring, applications, virtualisation, cloud environments, and log collection. To see how it compares with each specific alternative, we publish comparisons between Pandora FMS and other monitoring tools with feature-by-feature data. Is there a free option? Yes, the Open version, with no device limit.

Advantages of Pandora FMS

• It monitors every area (networks, servers, applications, and cloud environments) from a single centralised console, our Metaconsole.
• It scales to tens of thousands of devices through a distributed architecture.
• Network maps, reports, SLA management, event correlation, log collection, and inventory are integrated without stitching together third-party components that give birth to a Frankenstein’s monster.
• Designed and battle-tested by internal IT teams and MSPs managing multiple customers.

Disadvantages of Pandora FMS

• Despite how friendly we are, the user community is considerably smaller than those of Zabbix or Nagios.
• Because it covers so much ground, the console contains more options than a basic deployment requires, and we will not deny that it can feel slightly intimidating during the first week.

4. SolarWinds

Here we have one of the classic commercial network monitoring tools, now reorganised around its hybrid observability platform. It stands out for its automatic network and node discovery, topology maps, and a powerful interface that provides an at-a-glance view of network status. It is a very solid option for medium-sized and large enterprises that can afford its licences, which continue to rank among the most expensive on the market. Its modular design is also a double-edged sword. Each requirement, whether networks, servers, traffic, or configurations, is a separately licensed product, causing the total cost to rise quickly. Does it have a free version? No.

Advantages of SolarWinds

• Highly polished and mature graphical interface.
• Automatic network discovery and mapping, among the best in its segment.
• Large user community (THWACK) and extensive documentation.

Disadvantages of SolarWinds

• High price and module-based licensing, making every expansion more expensive.
• Each major feature lives in a different product, and obtaining a unified view requires purchasing several of them.
• It requires considerable Windows infrastructure for a comfortable deployment.

5. Icinga

Icinga was created in 2009 as a fork of Nagios and has since followed its own path, with considerably greater technical ambition than its parent. Icinga 2 rewrote the core, added declarative configuration, a complete REST API, and modern web modules. It is focused on complex networks and monitoring protocols, resources, and servers. It is the natural choice for anyone who wants the Nagios philosophy of full control, plugins, and plain text without carrying its technical debt. In return, it remains something of an “Ikea” tool that must be assembled. A complete solution usually involves combining Icinga with Grafana, a time-series database, and other components. Does it have a free version? Yes.

Advantages of Icinga

• Compatible with the Nagios plugin ecosystem, but with a modern core and API.
• Declarative and automatable configuration, designed for infrastructure as code.
• Good scalability through zones and a distributed architecture.

Disadvantages of Icinga

• Much of the configuration still lives in text files, powerful for those of us from the old school, but somewhat unfriendly by current standards.
• Steep learning curve and somewhat limited documentation for advanced scenarios.
• The complete experience requires integrating several components yourself.

6. ManageEngine OpManager

OpManager is the network monitoring tool from ManageEngine, Zoho’s IT software division. It covers the essentials competently, including SNMP, WMI, maps, alerts, reports, and virtualisation monitoring. It is also easy to install and reasonably priced for the capabilities it provides. For medium-sized businesses and organisations, it is a very reasonable option when we want a commercial solution without paying SolarWinds-level prices. In return, its limitations become apparent at the extremes. It falls short in very large environments or those with demanding event management requirements, while several features we might expect as standard, such as NetFlow, configuration management, or firewall monitoring, are separate products that cost extra. Does it have a free version? No, but it offers a free edition, although it is very limited in terms of devices.

Advantages of ManageEngine OpManager

• Easy to install and put into production on both Windows and Linux.
• Good price-to-functionality ratio.
• Clear interface with decent maps and dashboards out of the box.

Disadvantages of ManageEngine OpManager

• Important features are sold as separate add-ons, increasing the final bill.
• The user experience becomes more complicated when navigating between modules.
• Limited for large environments accustomed to event correlation and mass deployments.

7. Observium

A cross-platform, SNMP-based network monitoring tool with one undeniable strength: its graphs. Their level of detail and design make it ideal for dashboards that will end up in front of a manager impressed by flashing lights. It also includes automatic discovery and support for hundreds of vendors. It is very convenient for observing stable networks, but is it any good? We like it, although its philosophy is more contemplative than operational. Let me explain. Observium is designed to display the status and evolution of the network, but not so much to manage it. More advanced features and immediate updates require payment, while its data collection, essentially based on SNMP, limits what it can tell us. There is an optional Unix agent, but it is very limited. Does it have a free version? Yes, the Community edition, although its updates arrive later than those of the paid edition.

Advantages of Observium

• Detailed and polished graphs, among the best on this list for presentation to management.
• Simple and highly usable interface.
• Automatic discovery with support for an enormous variety of devices.

Disadvantages of Observium

• Focused almost exclusively on SNMP, with a rather limited optional Unix agent, meaning that anything not speaking SNMP barely exists.
• The alerting system is basic compared with a complete NMS.
• The free edition lags several months behind in updates and features.

8. PRTG Network Monitor

PRTG is the German entry on the list and probably the easiest commercial tool to use. Its model is based on sensors, with each monitored metric counting as one sensor, and its interface makes it possible to monitor a medium-sized network within hours, supported by a flexible alerting system and good reports. The free version, limited to 100 sensors, is enough for a small environment. As with any commitment to a particular model, its distinctive approach is also its main limitation, because as soon as the network grows, the number of sensors, and therefore the price, increases sharply, placing a ceiling on scalability. In addition, the server runs only on Windows, although a hosted version is available. You can see how it compares with a broader platform in the Pandora FMS vs PRTG Network Monitor comparison. Does it have a free version? No. There is that free 100-sensor edition, but it is not open source.

Advantages of PRTG Network Monitor

• Very easy to install and use. The time to the first useful data is minimal.
• Powerful and flexible alerting system.
• Good reports and access from mobile devices.

Disadvantages of PRTG Network Monitor

• Sensor-based costs rise quickly as the network grows.
• Limited scalability for large environments.
• Rigid when implementing custom checks outside its catalogue.
• Weak in server and application monitoring. Yes, it is an NMS rather than a complete platform, but today those boundaries are becoming blurred due to the need for more integrated operations.

9. WhatsUp Gold

Currently owned by Progress, it is a classic network monitoring tool for Windows environments. It stands out for its network discovery and generation of easy-to-understand maps, its ready-to-use inventory and several automated actions in response to events. Alerts arrive through the usual channels, and information is displayed in real time. This makes it a suitable tool if we live surrounded by those dreadful Windows stickers and want something straightforward, but its development is slow compared with the rest of the market, and its scalability ceiling rules it out for large environments. Does it have a free version? No.

Advantages of WhatsUp Gold

• Network discovery and maps that are easy to configure and understand.
• Fast deployment in Windows environments, with inventory and alerts ready out of the box.
• Gentle learning curve for Windows teams.

Disadvantages of WhatsUp Gold

• The console and navigation are not particularly intuitive.
• Configuration is split between the web interface and manual settings.
• Limited scalability and little depth in server and application monitoring.

10. OpenNMS

A veteran 100% open-source tool designed for large networks. It was built from the outset with the knowledge that size matters, so it offers strong scalability. It is one of the few open-source tools with real-world deployment stories among network operators. OpenNMS is distributed in two editions: Horizon, the community edition with a faster pace of changes and improvements, and Meridian, which is subscription-based and focused on greater stability. Its business model is complemented by support and consulting services. However, its enormous power comes at the cost of highly manual XML-based configuration, an interface that has never won a beauty contest, and one of the steepest learning curves on the list. And as its name reveals, it is a Network Management System. Outside the network, it relies almost entirely on SNMP and becomes limited if we also need to monitor servers or applications. Does it have a free version? Yes.

Advantages of OpenNMS

• True scalability for very large networks, something unusual in the open-source world.
• A 100% open-source project, with no restricted edition.
• Good integration of alarms and notifications, together with a solid technical community.

Disadvantages of OpenNMS

• Manual configuration that often produces installations that are difficult to decipher.
• Weak interface and reports when presenting information to non-technical audiences.
• Importing MIBs from different vendors causes more trouble than it reasonably should.
• Very limited outside pure network monitoring.

11. Cacti

This is a network graphing solution built on RRDtool that does one thing and, to be fair, does it well: collecting data through SNMP and displaying it in historical graphs, with a simple interface that works comfortably for installations the size of a LAN. The unfortunate part is that today this is no longer enough even to get started. Without serious events or reports, maps, or SLA management, Cacti is more of an add-on than a monitoring tool. Grafana and modern alternatives have eaten the last piece of toast it had left. Does it have a free version? Yes; that is the only type of version available.

Advantages of Cacti

• Easy to install and use.
• It delivers what it promises: uncomplicated historical SNMP graphs.

Disadvantages of Cacti

• Very basic.
• Does not scale well.
• It lacks essential built-in features for a monitoring environment, such as events, advanced notifications, reports, SLA management… Third-party plugins can add thresholds and alerts, but you have to stitch everything together yourself.

12. Datadog

We now reach the leading SaaS platform for observability, providing metrics, logs, traces, and network monitoring through NPM and SNMP device monitoring in a cloud platform with hundreds of ready-to-use integrations. This gives it its greatest advantage: for cloud environments and DevOps teams, the time between signing up and seeing data is measured in minutes. Its ability to correlate the network with applications and infrastructure is also among the best available, and that deserves recognition. The downside, however, is familiar to anyone who has ever received its invoice. Its pricing model based on hosts, metrics, and modules makes the final cost difficult to predict and easy to drive up. In traditional on-premise networks with large numbers of SNMP devices, its depth is also more limited than that of a traditional NMS. Does it have a free version? No. It is SaaS, with a permanent free plan offering up to five hosts and one day of retention, which is useful for testing and little else, as well as a full trial of the paid version.

Advantages of Datadog

• Immediate deployment because monitoring is delivered as a service, with no infrastructure of our own to maintain.
• Hundreds of integrations and native correlation across networks, infrastructure, applications, and logs.
• Excellent user experience and dashboards.

Disadvantages of Datadog

• High and difficult-to-predict cost.
• Our monitoring data lives outside our infrastructure, which does not suit every environment.
• Less depth in traditional SNMP networks than a conventional NMS.

13. LogicMonitor

We continue with another SaaS platform for monitoring hybrid infrastructure, designed for enterprises and MSPs. Its deployment is based on collectors installed within our network that monitor without agents using SNMP, WMI and APIs, with automatic discovery and thousands of ready-made vendor templates. Once again, we get a fast deployment for heterogeneous environments, all brought together in a single view. In the convenience league, it competes with Datadog while offering a more traditional infrastructure-focused approach. The drawbacks are predictable: convenience does not come for free, the platform may be oversized for smaller organisations, and deep customisation is more limited than with open-source platforms. Does it have a free version? No. Once again, it is SaaS with a free trial.

Advantages of LogicMonitor

• Fast agentless deployment, with automatic discovery and templates for thousands of devices.
• Good coverage of hybrid environments, including networks, servers, cloud and storage.
• Also designed for MSPs, with multitenant support.

Disadvantages of LogicMonitor

• High price for smaller organisations with limited budgets.
• Limited customisation compared with open-source alternatives.
• Total dependence on the cloud service.

14. Auvik

Another SaaS platform focused specifically on networks and highly popular among MSPs. Its value lies in automating tedious tasks: it discovers the network, creates and continuously updates topology maps in real time, automatically backs up device configurations and analyses traffic. If we manage dozens of networks belonging to different customers, it can save a considerable number of hours. Once again, every sardine has its bone, and its main focus also becomes its limitation because Auvik’s centre of gravity remains the network. It has expanded its scope with Windows server monitoring and SaaS management, but these are relatively recent additions without the depth of a complete platform, so it falls short for application monitoring. In addition, its per-network-device pricing model, which charges for “major” elements such as switches and routers, is not designed for shallow pockets. Does it have a free version? No. It is SaaS with a free trial.

Advantages of Auvik

• Automatic topology maps that are always up to date.
• Configuration backup and change control for network devices.
• Native multitenancy, ideal for MSPs.

Disadvantages of Auvik

• Primarily focused on networks. Its server and application coverage is recent and considerably less comprehensive.
• Per-device pricing that rises quickly in large networks.
• Dependence on SaaS for something as critical as maintaining visibility over our own network.

15. Site24x7

We now reach Zoho’s all-in-one SaaS monitoring solution, from the same company behind ManageEngine. Site24x7 allows us to monitor websites, servers, networks, cloud environments and user experience through a single service at a very competitive price. For a small or medium-sized business that wants broad coverage without deploying its own infrastructure or going bankrupt, it is one of the most sensible options on the market. The only issue is that, as is often the case with affordable all-in-one products, breadth takes priority over depth. Its network monitoring is competent, but it does not reach the level of detail provided by a specialised NMS, while the interface contains so many modules that finding specific features can sometimes be difficult. Does it have a free version? No. It is SaaS, with a permanent free plan covering five monitors, which is well hidden but does exist, and paid plans starting at very low prices.

Advantages of Site24x7

• A coverage-to-price ratio that is difficult to beat in the SaaS market.
• Websites, servers, networks and cloud environments within the same service.
• Simple deployment, with no infrastructure of our own.

Disadvantages of Site24x7

• Less depth in network monitoring than specialised tools.
• Cluttered interface due to the number of modules.
• Advanced customisation falls short in complex environments.

16. Checkmk

Checkmk is another German tool that began within the Nagios ecosystem and has evolved into something far more ambitious: an infrastructure monitoring platform that is quick to deploy, with automatic discovery of services and its own lightweight agents. It is also available as the Raw edition, an appropriate name for something that is 100% open source, alongside commercial editions offering greater automation and scalability. The difference is not merely cosmetic: Raw still runs on the Nagios core and comfortably handles up to several hundred hosts per server, while the commercial editions replace it with their own engine, Checkmk Micro Core, whose per-server performance is matched by very few options on this list, reaching thousands of hosts per instance. If we want serious on-premise monitoring without the handcrafted suffering of Nagios or the learning curve of Zabbix, this is the option. The drawbacks? A dense interface with its own logic, which takes time to understand. Naturally, the most attractive features, such as advanced reports, improved dashboards and managed scalability, are reserved for the paid editions. Does it have a free version? Yes, the aptly named Raw edition.

Advantages of Checkmk

• Very fast deployment and automatic discovery. It can go from zero to monitoring in just a few hours.
• Excellent performance per server in its commercial editions, supporting thousands of hosts per instance.
• Commercial editions with mature automation and distributed monitoring.

Disadvantages of Checkmk

• Dense interface and proprietary concepts that require adaptation.
• Advanced features are not included in the free edition.
• Less flexible than Zabbix or Pandora FMS for highly customised use cases.

17. LibreNMS

Born as a community fork of Observium, it has grown into one of the most popular open-source network monitoring tools. It provides automatic discovery through SNMP, support for a huge variety of vendors, configurable alerts, a REST API and an active community that constantly publishes improvements. And everything is free, with no restricted editions. LibreNMS fits our puzzle if we manage medium-sized networks with technical teams that embrace open-source culture. Its limitations are those of the open-source model. Scaling requires us to design the architecture ourselves, there is no formal commercial support behind it and, as with Observium, its world quickly ends beyond SNMP. Does it have a free version? Yes. In fact, that is the only version it has.

Advantages of LibreNMS

• Completely free and open source, with no withheld features.
• Very active community and continuous development.
• Automatic discovery and extremely broad support for SNMP devices.
• REST API for integrating it with anything we need.

Disadvantages of LibreNMS

• Focused on SNMP, with limited visibility into servers and applications.
• Scaling to large networks requires in-house architecture work.
• No official commercial support, meaning our safety net will be the community, and those nets are woven with holes that are too large for professional requirements.

18. Centreon

We travel to France to explore a monitoring tool that began, unsurprisingly, within the Nagios ecosystem, but has gradually replaced its internal components with its own engine and technologies. Its main strength is distributed monitoring, with an architecture based on central servers and remote pollers designed for NOCs monitoring multiple sites or segmented infrastructures. The open-source edition is functional, but the components that make it stand out in demanding environments, such as advanced reports, maps and automatic discovery, belong to the commercial editions. Therefore, it is worth evaluating the paid product if our environment has demanding requirements. You can find a detailed contrast in the Pandora FMS vs Centreon comparison. Does it have a free version? Yes, with the most advanced capabilities included in the commercial versions.

Advantages of Centreon

• Mature distributed architecture, ideal for multisite NOCs.
• Hundreds of connectors (plugin packs) that speed up deployment.
• Compatibility with the plugin ecosystem inherited from Nagios.

Disadvantages of Centreon

• We must pay for its differentiating features.
• An architecture made up of several components that must be administered and maintained.
• Smaller community outside French-speaking markets.

19. Prometheus + Grafana

Prometheus takes its name from the titan who stole fire from the gods and gave it to frightened humans, who eventually used it to manufacture chips, which is why I am writing this. What this tool provides is metrics through a pull model that queries exporters deployed alongside whatever we want to monitor. Grafana is its natural partner, the de facto standard for dashboards, and together they rule cloud-native monitoring. Translated from mythology, this means that if our IT Olympus is built on Kubernetes, microservices and containers, we are probably already using them, and rightly so. PromQL, the flexibility of its metrics and the surrounding ecosystem have no rival in those lands. However, they are not a network monitoring suite, and that must be made clear. There is no topology discovery or trap management worthy of the name. Nor are inventory or SLA reports included by default. Monitoring the network with this combination means assembling SNMP and blackbox exporters, then adding Alertmanager for alerts, separate long-term storage and more, while maintaining the entire stack. It certainly has power, but in return it requires an engineering project rather than providing a turnkey solution. Does it have a free version? Yes, both are open source, although Grafana also offers a paid SaaS service.

Advantages of Prometheus + Grafana

• The de facto standard for Kubernetes and cloud-native environments, with an enormous ecosystem.
• PromQL makes it possible to exploit metrics with a level of flexibility few tools can match.
• Grafana sets the highest standard for dashboards and integrates with dozens of data sources.

Disadvantages of Prometheus + Grafana

• It is not an NMS. It does not include network discovery, topology or inventory.
• It requires continuous configuration, component integration and maintenance.
• Long-term retention and high availability require additional components, such as Thanos or Mimir.

Other network monitoring tools worth knowing

We have built the Yellow Pages of today’s landscape, a reference that reveals my age, but “don’t go away, there’s still more”, because two names with a long history remain outside the main list and may still appear on our radar when we search for solutions.

• Zenoss was a popular alternative for agentless monitoring of networks, servers and virtualisation for many years. Today, it has shifted towards the enterprise market, the business kind rather than Star Trek’s Enterprise, with its cloud platform. This means it appears less frequently in new evaluation processes, especially because its former Community edition is no longer a realistic option.
• Opsview is another Nagios derivative, a platform that has produced more descendants than Genghis Khan. Focused on network and application monitoring for enterprises, it remains active under the ITRS umbrella, although it has less momentum than the main options on our list. If it has made your shortlist for any reason, it is worth reviewing the Pandora FMS vs Opsview comparison.

And now for a note on archaeology. GroundWork, Monitis and Op5 Monitor, which appeared in this comparison for many years, are now historical solutions with little presence compared with more modern alternatives.
We mention them so that, if you come across one in an inherited installation, you know that you have not gone mad and that we have not overlooked them in our research, because they really did exist.

Tools designed for MSPs and RMM

Let us talk about the building next door, because there is a neighbouring category that increasingly appears in network monitoring tool evaluations and should be properly understood: RMM software, or remote monitoring and management.
These are not monitoring platforms like Nagios, Pandora FMS or SolarWinds. Their centre of gravity is endpoint management, remote support, patching and automation, with network monitoring as just one more piece of the Lego set.
If you are an MSP managing dozens of customers, that combination may be exactly what you need. However, if your objective is to monitor a corporate network in depth, following this path will leave you short of your destination.

• NinjaOne is one of the highest-rated RMM platforms on the market. It includes endpoint management, patching, remote access, backups and automation through a polished interface, together with SNMP monitoring for network devices. It fits MSPs and IT teams that prioritise workstation and server management over detailed visibility into network equipment. If you are deciding between an RMM approach and a monitoring platform, the Pandora FMS vs NinjaOne comparison explains the differences.
• Atera targets the same market, but uses a distinctive pricing model in which you pay per technician rather than per device. This makes it attractive to small MSPs and compact IT departments looking for RMM, service desk and billing capabilities within a single product. Its network monitoring is functional, although in truth quite basic. It may be sufficient for overseeing the infrastructure of small customers, but it is inadequate as an NMS for a network with more demanding requirements.

Here is a quick rule for deciding.

• If our challenge is managing many customers and many endpoints, we should look at RMM.
• If the challenge is the network itself, we are better off sticking to the main list.

Conclusion: which tool to choose for each use case

After travelling through every corner of the market, let us rise once more to a position where we can gain perspective and make a decision, because choosing a monitoring tool is not the Kobayashi Maru. In this case, there is a solution… Provided that we define the scenario properly before choosing.
Obviously, we should point out that we do not know each other yet and are unfamiliar with your specific situation. However, after years of installing and dismantling these tools, here are some recommendations we have picked up along the way:

• If you are looking for open source and customisation, with a technical team willing to invest time, we recommend Nagios if you already know it, Zabbix, Icinga, LibreNMS or Checkmk. Try them in that order and you will achieve maximum control with zero licensing costs, but you will pay the bill in engineering time.
• If you need a broad platform covering infrastructure, networks, servers, applications and hybrid environments from a single console: Pandora FMS, SolarWinds, ManageEngine or PRTG, depending on your budget, organisation size and how much you value open source.
• If you want SaaS visibility or live in the cloud: Datadog, Auvik, LogicMonitor or Site24x7 are the main options. Deployment will take hours, and you will not have to maintain your own infrastructure. In return, you will have yet another subscription in your life, probably the thousandth, and your data will live outside your organisation, which may conflict with certain internal policies.
• If you are an MSP or your priorities are endpoints, remote support and automation: NinjaOne and Atera are the options closest to the RMM approach.

Whatever your situation, do not choose based on the attractive demo. It will always be optimised to impress during the first twenty minutes, but not throughout the rest of your life with the tool.
Instead, return to the checklist at the beginning and use your real figures for devices, sites and team capacity. Then consider choosing your monitoring software as if it were a marriage, and for once, I am not joking.
This is a tool that organisations replace only once every several years, and the consequences of a poor decision become apparent late, when we have already built everything on top of it.
If you still want to keep comparing and explore concrete data feature by feature, our monitoring tool comparison is the next stop.
With that, you will be able to choose the best sensors for what is probably the nervous and circulatory system of a modern IT infrastructure: the network.