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Agentless Network Monitoring: An Introductory Guide

By: NetreoNoaa
August 10, 2023

From communication and collaboration to data storage and sharing, networks are critical to almost every business operation today. Thus, monitoring the reliability and security of your network infrastructure is more critical than ever.

Network monitoring entails observing and analyzing network traffic to identify issues, optimize performance and ensure security. In addition, monitoring involves collecting and analyzing network performance metrics to get visibility into the health and performance of your network infrastructure.

Agentless network monitoring is one of many approaches organizations use to monitor network infrastructure efficiently. This guide will focus on everything you need to know about agentless monitoring, from its benefits to tools for implementation.

First of all, let’s define the fundamental term.

What Is Agentless Network Monitoring?

Agentless network monitoring is observing network infrastructure without installing any agents on the devices under management.

Instead, remote access protocols, such as Simple Network Management Protocol (SNMP), Windows Management Instrumentation (WMI), and Secure Shell (SSH), or APIs access and collect data for network infrastructure monitoring and management.

This method is convenient and less intrusive since you can monitor and troubleshoot the performance of your network assets without any manual installation and maintenance on individual devices.

Why Use Agentless Network Monitoring?

Network monitoring benefits organizations in various ways, regardless of their size. Increased visibility across your infrastructure enables IT teams to reduce downtime and improve business productivity and finances. Also, network visibility helps your team identify and solve issues early and reduce exposure to malicious attacks.

The great thing is that agentless network monitoring offers these benefits without additional overhead, software configuration, and manual installation hassles. In addition, agentless network monitoring makes it easier to configure, deploy and manage network infrastructures.

What Is the Difference Between Agent and Agentless Network Monitoring?

Agents are basically software applications installed in end network devices. Unlike the agentless approach, agent network monitoring uses these software apps to monitor network devices.  Agents collect device data and send it to a monitoring tool for unidirectional tracking and management.

The agent approach provides granular detail, since you can customize the metrics that agents collect. Agents are also more resilient to connectivity issues. However, most agents are tied to a specific vendor, require software installation and are resource intensive.

Agentless monitoring, on the other hand, uses APIs, standards, and protocols like SNMP to collect data. Thus, there’s no need to install and manage additional software on target devices.

This single difference makes agentless more agile, easier to scale, and less resource intensive. Agentless monitoring also supports more devices, since the protocols are usually built into common networking devices. However, agentless monitoring creates more network traffic and visibility is limited to only what your protocols expose.

To summarize, the differences between agent and agentless network monitoring lie in the following:

  • Resource intensity – The agentless approach requires fewer resources since no agent software installation and management are needed.
  • Cost – Agentless monitoring saves you initial setup and maintenance costs.
  • Deployment – Agentless monitoring tools are easier to deploy across various landscapes. Agent monitoring tools require agents to be deployed on each target device.
  • Data and metrics – Agents provide granular data since they can access data collected and can monitor device-level metrics not accessible through protocols.
  • Network connectivity – Agent monitoring is bandwidth efficient because data is collected locally. Agentless, however, requires a much higher bandwidth since data has to be transported via a remote data collector.

Agent vs. Agentless Network Monitoring: Which Should You Choose?

Agentless network monitoring is highly scalable and shines over agent network monitoring when considering its vendor-neutral nature. This agentless approach is better adapted and more compatible with the ever-changing, distributed IaaS and PaaS cloud landscape. However, agents are preferred when protocols can’t provide the visibility you want, and your network connectivity is poor or restricted.

So if you’re going for scalability, want less operational overhead, and have fewer resources with robust connectivity, go for agentless monitoring.

When Should You Do Agentless Monitoring for Applications?

Agentless monitoring can be implemented in many types of network devices, including servers, desktops, switches and routers.

However, agentless monitoring is well-suited for virtual applications and devices often not installed on your network—for example, your Hypervisors, virtual desktops and cloud servers like Amazon EC2.

These applications and devices often have web service and RESTful APIs or support SNMP polling and the SMI-S standard for agentless monitoring. For example, WMI monitors Microsoft Windows software, and hyperconverged infrastructure (HCI) uses RESTful APIs to gather data.

Other situations where you should consider agentless monitoring include:

  • when installing agents is not feasible because of your resource-constrained environments, hardware or software restrictions
  • times when your highly distributed cloud environments hold applications and services hosted on third-party infrastructure
  • when you need temporary environments for testing or rapid application deployment (This is necessary for today’s technological landscape.)
  • when your network devices are of the same type or support similar network protocols

How Do You Do Agentless Network Monitoring?

To perform agentless network monitoring and simplify monitoring for complex network software, you need to:

  1. Identify and determine the devices you want to monitor.
  2. Select a tool like Netreo as your source of truth for agentless monitoring. This is significant because your network monitoring tool shouldn’t hinder you; it should support the protocols and address your monitoring challenges.
  3. Identify all devices connected to your network by IP address, hostname, and appropriate protocols and configure your monitoring tool to access the network devices you want to monitor.
  4. Analyze network traffic and define the key performance indicators (KPIs) and metrics you want to monitor. A few of these metrics are bandwidth usage and latency.
  5. Set up thresholds and alerts to notify you when potential network issues arise. This is key for a proactive monitoring strategy.
  6. Monitor, collect, analyze, and visualize the data to identify trends and network performance, as well as track changes over time.

Tools for Agentless Network Monitoring

There are various tools available for agentless network monitoring. However, while these tools monitor similar metrics, they’re different. Thus, it’s best to consider a few things before committing to a tool.

Need an idea of what to look out for? We have a comprehensive article on how to pick a network monitoring tool that will fit your needs.

Let’s look at a few tools you should consider for agentless network monitoring.


Netreo offers a comprehensive network and IT infrastructure-monitoring suite that consolidates multiple capabilities into a single solution. Thus, this makes Netreo easily customizable and cost-effective.

This solution provides event filtering, baselining, automation, root-cause analysis and SLA-based reporting, along with other advanced features. Netreo also automatically detects topology with a continuously synchronized view of active incidents.

By serving as your organization’s single source of truth, Netreo allows you to:

  • respond to issues swiftly, thus reducing mean time to resolve (MTTR) and creates time for IT teams to focus on high-value functions
  • automate tasks and troubleshooting processes
  • simplify complexity and provide your team with insights using its AIOps engine
  • provide accurate and reliable dependency and service maps
  • get visibility and visualize your network’s topological configuration using graphical reports


Prometheus is an open-source, agentless network monitoring tool suitable for businesses of all sizes for time-series data.

This tool monitors services and applications operating on various platforms by obtaining data straight from the target service via protocols, much like every agentless tool.

In addition, with its Alertmanager feature, you can receive notifications via various channels and silence alerts if needed.

While Prometheus supports many integrations and plugins, it does require configuration and setup for practical use.


Nagios supports agent and agentless network monitoring for Linux, Unix, and Windows systems.

This tool has a free version, Nagios Core, and a commercial version, Nagios XI, which has additional functionality for large configurations. However, ample time is often required when configuring and setting up customizations.


Another open-source network monitoring tool is Zabbix. This tool supports agent-based and agentless monitoring for real-time monitoring, alerting, and reporting of network monitoring.

It has a great web UX interface and features like anomaly detection and root-cause analysis. The downsides of this tool are the time and effort to set it up and the cost of its ancillary services.


With over 2,000 monitoring options, including flow monitoring and configuration management, OpManager by ManageEngine comes in three different editions: free, professional and enterprise.

This tool has a discovery rule engine and supports several performance monitors for various devices from a single console.

While its free edition comes with a limit, its professional edition doesn’t limit the number of monitors you can run.

A few cons are the limited customizations due to the edition subscribed and its resource-intensive nature, which can affect the host system’s performance.

Agentless Network Monitoring With Netreo

With its numerous features, Netreo is an excellent choice for managing multiple networks. Furthermore, Netreo can be used alone or integrated with tools like Retrace APM to gain even deeper insights into your infrastructure and applications.

This powerful combination offers code-level application monitoring, error-tracking and a better end-user experience, while providing excellent economic and infrastructure benefits.

So unlock the full potential of your IT infrastructure and experience the power of Netreo for yourself. Request a demo today!

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