Nagios Core

Name: Nagios Core
Brand: Nagios Core

Free, open-source infrastructure monitoring engine for servers, networks, and services on Linux.

softwareMonitoring & Loggingopen source monitoringnetwork monitoring server monitoring

What is Nagios Core?

Nagios Core is a free, open-source monitoring solution used to track the health of servers, network infrastructure, and services. It monitors CPU, memory, disk usage, and running processes on Linux, Windows, and Unix systems, along with network devices like switches, routers, firewalls, and load balancers, and services such as DNS, DHCP, FTP, SSH, email, and databases. As the original engine behind the broader Nagios monitoring ecosystem, Core is extensible through thousands of community-developed plugins and integrations, letting it monitor almost anything with a status that can be checked. It's distributed under the GPL v2 license with full source code available on GitHub, and runs on major Linux distributions including Ubuntu, CentOS, Debian, and RHEL.

SpecificationsAI-estimated

deploymentSelf-hosted

open source✅ Yes

Key Features of Nagios Core

Monitors CPU, memory, disk usage, and processes on Linux, Windows, and Unix systems.

Tracks network infrastructure including switches, routers, firewalls, and load balancers.

Monitors web services for uptime, response time, and content verification.

Checks common services such as DNS, DHCP, FTP, SSH, email, and databases.

Extensible through thousands of community-developed plugins covering nearly any monitorable system.

Fully open source under the GPL v2 license, with source code available on GitHub for customization.

Runs on major Linux distributions including Ubuntu, CentOS, Debian, and Red Hat Enterprise Linux.

Forms the free core engine underlying Nagios' broader paid monitoring products.

Use Cases for Nagios Core

Monitoring Linux server health

Tracks CPU, memory, disk, and process-level metrics on Linux and Unix servers.

Network device monitoring

Watches the status of routers, switches, firewalls, and load balancers across the network.

Service uptime checks

Verifies DNS, email, database, and other service availability and response times.

Custom monitoring via plugins

Thousands of community plugins extend Nagios Core to monitor specialized or custom systems.

Pros & Cons of Nagios Core

Pros

Completely free with no licensing costs or feature limitations
Massive community plugin ecosystem covers nearly any system worth monitoring
Full source code access allows deep customization for specific environments
Long track record and large install base since 2002

Cons

Linux-only; no native Windows or Mac server installation
Interface and initial configuration feel dated compared to newer monitoring tools
Setup and plugin management require more manual work than commercial alternatives with GUIs

Frequently Asked Questions

Is Nagios Core free?

Yes, Nagios Core is completely free and open source under the GPL v2 license.

What operating systems does Nagios Core run on?

Nagios Core runs on Linux distributions including Ubuntu, CentOS, Debian, and Red Hat Enterprise Linux.

Can Nagios Core monitor Windows servers?

Yes, though Nagios Core itself runs on Linux, it can monitor Windows servers and services remotely via plugins.

How is Nagios Core extended?

It's extended through thousands of community-developed plugins that add checks for almost any system or service.

Pricing Overview

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Free

Detailed plans are not listed. Visit the official website for pricing information.

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