22 Best Free Open Source IT Tools for IT Admins (2026): Nagios, Checkmk, Wazuh SIEM, osTicket, Snipe-IT

Quick answer: You can run a complete IT department on free, open-source tools. The most popular choices are Nagios Core, Checkmk Community or Zabbix for network monitoring, Wazuh with an OpenSearch-based dashboard as a SIEM (including Active Directory log monitoring), osTicket for the helpdesk, and Snipe-IT for asset management.

Best starter stack for a small company: Checkmk Community (monitoring) + Wazuh (security and AD logs) + osTicket (tickets) + Snipe-IT (assets) + RustDesk (remote support). All five are self-hosted and have no licence cost; you only pay for the server and your time.

Last updated: 29 October 2026. Licence and edition details were checked on the official project pages (see sources). Written by an IT engineer who uses these tools in real environments.

Paid IT tools like SolarWinds, ServiceNow, Splunk or ManageEngine are powerful, but their licence costs are often too high for small and mid-size companies, schools and startups, especially in India. The good news is that for almost every paid IT tool, there is a mature free and open-source alternative used by thousands of companies worldwide.

In this guide I have listed the best free open-source IT tools for IT admins in 2026, category by category: network monitoring, SIEM and log monitoring, helpdesk, asset management, IPAM, remote support, vulnerability scanning, password management, documentation, backup and firewall. For each tool you will see what it does, who it suits and its licence.

Table of contents

1. All tools at a glance
2. Network and server monitoring: Nagios, Checkmk, Zabbix, LibreNMS, Uptime Kuma
3. SIEM and log monitoring: Wazuh and OpenSearch Dashboards
4. How to monitor Active Directory logs for free (step by step)
5. Helpdesk and ticketing: osTicket, Zammad, GLPI
6. IT asset management: Snipe-IT, GLPI, OCS Inventory
7. Network documentation and IPAM: NetBox, phpIPAM
8. Remote support: RustDesk, MeshCentral
9. Vulnerability scanning: Greenbone OpenVAS
10. Password manager, documentation, backup and firewall
11. Recommended free IT stack for a small company
12. Before you deploy: 7 things to plan
13. FAQ
14. Sources

All tools at a glance

Category	Free open-source tool	Licence	Paid tool it replaces
Network monitoring	Nagios Core	GPL v2	Nagios XI, PRTG
Network monitoring	Checkmk Community (formerly Raw Edition)	GPL v2	PRTG, SolarWinds
Network monitoring	Zabbix	AGPL v3 (7.0+)	SolarWinds, PRTG
Network monitoring	LibreNMS	GPL v3	SolarWinds NPM
Uptime monitoring	Uptime Kuma	MIT	UptimeRobot, Pingdom
SIEM / XDR	Wazuh	GPL v2 (dashboard: Apache 2.0)	Splunk, QRadar
Log search and dashboards	OpenSearch + OpenSearch Dashboards	Apache 2.0	Elastic / Splunk
Helpdesk	osTicket	GPL v2	Freshdesk, ServiceDesk Plus
Helpdesk	Zammad	AGPL v3	Zendesk, Freshdesk
Helpdesk + assets	GLPI	GPL v3	ServiceNow (basic ITSM)
Asset management	Snipe-IT	AGPL v3	Asset Explorer, Lansweeper
Inventory agent	OCS Inventory NG	GPL v2	Lansweeper
IPAM / network docs	NetBox	Apache 2.0	SolarWinds IPAM
IPAM	phpIPAM	GPL v3	Excel sheets
Remote support	RustDesk	AGPL v3	AnyDesk, TeamViewer
Remote management	MeshCentral	Apache 2.0	ConnectWise, TeamViewer
Vulnerability scanning	Greenbone Community Edition (OpenVAS)	AGPL / GPL	Nessus, Qualys
Password manager	Vaultwarden	AGPL v3	1Password, LastPass
Documentation / wiki	BookStack	MIT	Confluence
Backup	UrBackup	AGPL v3	Veeam Agent, Acronis
Firewall	OPNsense	BSD 2-Clause	Sophos, Fortinet (basic)

Note: "free" means no licence fee for the open-source edition. Many of these projects also sell paid editions, hosting or support, which is how they fund development.

Network and server monitoring

A monitoring tool checks your servers, switches, firewalls, printers and services every few minutes and alerts you (email, Telegram, Teams) before users call the helpdesk.

1. Nagios Core

Nagios is the "grandfather" of open-source monitoring. Nagios Core is the free version; Nagios XI is the paid version with a nicer web interface.

• Best for: admins who like full control and are comfortable with Linux and text config files.
• Strengths: very stable, thousands of community plugins, monitors almost anything (ping, CPU, disk, services, HTTP, SNMP devices).
• Weak points: old-style interface, configuration is done in text files, steep learning curve.

2. Checkmk Community (formerly Checkmk Raw Edition)

In March 2026 Checkmk renamed its editions. The free, 100% open-source edition is now called Checkmk Community (previously "Checkmk Raw"). Functionality did not change.

• Best for: small and mid-size companies that want Nagios-level power with a modern web UI.
• Strengths: automatic service discovery (add a host and it finds CPU, disks, interfaces and services for you), ready-made checks for Windows, Linux, switches and firewalls, all configured from the browser.
• Weak points: some advanced features (agent bakery, advanced reporting) are only in the paid Pro/Ultimate editions; support is community-only.

3. Zabbix

• Best for: bigger networks and companies that need templates, dashboards and scale.
• Strengths: fully free (no paid "enterprise edition"), powerful templates for Windows, Linux, VMware, Cisco and many vendors, good dashboards, network discovery. Licence is AGPL v3 from Zabbix 7.0.
• Weak points: more complex to tune; needs a proper database server for big setups.

4. LibreNMS

• Best for: network teams with many switches, routers and firewalls.
• Strengths: SNMP auto-discovery, automatic network maps, port bandwidth graphs, supports a huge list of network vendors.
• Weak points: focused on network devices, less suited for deep application monitoring.

5. Uptime Kuma

• Best for: simple "is it up or down?" checks for websites, ports and services, plus a public status page.
• Strengths: installs in minutes with Docker, beautiful UI, notifications to Telegram, Teams, Slack, email and more.
• Weak points: not a full infrastructure monitoring tool (no deep CPU/disk/SNMP monitoring).

Which monitoring tool should you choose?

Your situation	Pick
Small/mid company, want quick setup and a modern UI	Checkmk Community
Large network, many templates, fully free	Zabbix
Mostly switches, routers and bandwidth graphs	LibreNMS
Already know Nagios, want maximum flexibility	Nagios Core
Only need website/service uptime and alerts	Uptime Kuma

Tip: want beautiful graphs? Many teams add Grafana on top of Zabbix or Prometheus for dashboards.

SIEM and log monitoring: Wazuh and OpenSearch Dashboards

A SIEM (Security Information and Event Management) collects logs from servers, PCs, firewalls and Active Directory in one place, finds suspicious activity and alerts you. Commercial SIEMs like Splunk or QRadar are expensive. The two most common free options are:

6. Wazuh (free SIEM + XDR)

Wazuh is the most popular open-source security platform. It has three parts:

• Wazuh agent on Windows, Linux and macOS machines: collects logs and security data.
• Wazuh server and indexer: analyse and store the data (the indexer is based on OpenSearch).
• Wazuh dashboard: the web interface, which is a fork of OpenSearch Dashboards.

What Wazuh can do: Windows and Linux log collection, file integrity monitoring (including the Windows Registry), malware detection, vulnerability detection, security configuration assessment (CIS-style checks), active response (for example blocking an attacking IP), container security and system inventory.

Best for: any company that needs security monitoring, audit logs for ISO 27001 / SOC 2, and Active Directory monitoring without paying for Splunk.

7. OpenSearch + OpenSearch Dashboards

OpenSearch is the open-source search and analytics engine (a fork of Elasticsearch, now under the OpenSearch Software Foundation), and OpenSearch Dashboards is its Kibana-like web interface. You can send any logs (firewall syslog, Windows events, application logs) into OpenSearch and build your own searches, dashboards and alerts.

Wazuh vs plain OpenSearch: OpenSearch is a blank canvas: very flexible, but you build the detection rules and dashboards yourself. Wazuh gives you OpenSearch-based storage and dashboards plus ready-made agents, security rules and compliance reports. For most IT teams, start with Wazuh.

How to monitor Active Directory logs for free (step by step)

This is the most common question I get: "How do I see who logged in, who got locked out, and who added a user to Domain Admins, without buying a tool?" Here is the simple path with Wazuh:

1. Install Wazuh on a Linux server or VM using the official quickstart (an all-in-one installation is enough for a small company).
2. Enable auditing on your domain controllers. In Group Policy, edit the Default Domain Controllers Policy > Computer Configuration > Policies > Windows Settings > Security Settings > Advanced Audit Policy Configuration and enable Success and Failure auditing for Account Logon, Account Management, Logon/Logoff and DS Access.
3. Install the Wazuh agent on every domain controller. By default the agent collects the System, Application and Security event channels, and the Security channel contains logons, logoffs, user and group changes and audit policy changes.
4. (Optional) Make the Security channel explicit in the agent's ossec.conf file (C:\Program Files (x86)\ossec-agent\ossec.conf):

   <localfile>
     <location>Security</location>
     <log_format>eventchannel</log_format>
   </localfile>

   Then restart the agent in an admin PowerShell: Restart-Service -Name wazuh
5. Search and alert on these key Active Directory event IDs in the Wazuh dashboard:

Event ID	What it means	Why it matters
4624	Successful logon	Who logged in, from where
4625	Failed logon	Password guessing or brute force
4740	Account locked out	Find the source of repeated lockouts
4720 / 4726	User account created / deleted	Unexpected new or removed accounts
4724	Password reset by an admin	Track helpdesk and admin resets
4728 / 4732 / 4756	Member added to a security group	Someone added to Domain Admins or other privileged groups
4672	Special (admin) privileges assigned at logon	Admin account usage
4771	Kerberos pre-authentication failed	Wrong password attempts on the domain
1102	Security audit log cleared	Possible attacker covering tracks: always investigate

Tip: create alerts for 4740 (lockouts), 4728/4732/4756 (privileged group changes) and 1102 (log cleared). These three alone catch many real incidents.

Helpdesk and ticketing

8. osTicket

osTicket is one of the most widely used free helpdesk systems. Users email support@yourcompany.com or use a web portal, and every request becomes a ticket.

• Licence: GPL v2. Still actively maintained with regular releases.
• Features: email-to-ticket, help topics, departments, SLA plans, auto-assignment, canned responses, a customer portal and a knowledge base.
• Best for: small and mid-size IT teams that want a simple, proven helpdesk on normal PHP/MySQL hosting.
• Weak points: the interface looks dated, and it has no built-in asset management.

9. Zammad

• Licence: AGPL v3.
• Why choose it: a modern, fast interface with email, chat, phone and social channels in one place. A good choice if osTicket feels too old-fashioned.

10. GLPI

• Licence: GPL v3.
• Why choose it: GLPI combines helpdesk + IT asset management + inventory in one tool. Tickets can be linked directly to the user's laptop, printer or software licence. A good fit for teams that want an ITIL-style tool for free.

IT asset management

11. Snipe-IT

Snipe-IT is the most popular free asset management tool for IT teams.

• Licence: AGPL v3, maintained by Grokability. Version 8.x is the current release line in 2026.
• Features: tracks laptops, desktops, mobiles, accessories, consumables and software licences; check-in/check-out to employees; QR/barcode labels; audit history; licence expiry alerts; LDAP/Active Directory user sync; SAML SSO; a full REST API. No limit on users or assets in the self-hosted version.
• Best for: knowing exactly which employee has which laptop, charger and licence, and for clean handover when someone leaves.
• Tech: PHP (Laravel) with MySQL/MariaDB; runs on a LAMP server or Docker.

12. GLPI (again) and 13. OCS Inventory NG

Snipe-IT is mostly manual (you add assets yourself or import a CSV). If you want automatic hardware and software inventory from every PC, use GLPI with its inventory agent, or OCS Inventory NG agents that report hardware, installed software and serial numbers automatically.

Network documentation and IPAM

14. NetBox

NetBox (Apache 2.0) is the standard open-source tool for documenting networks: IP addresses and subnets (IPAM), VLANs, racks, devices, cables and circuits. It replaces the "IP address Excel sheet" that every IT team has.

15. phpIPAM

phpIPAM (GPL v3) is a simpler IP address manager. It can scan subnets to find used and free IPs. Great for small teams that only need IP tracking.

Tip: planning subnets? Use our free Subnet Calculator.

Remote support

16. RustDesk

RustDesk (AGPL v3) is an open-source alternative to AnyDesk and TeamViewer. You can self-host your own relay server, so remote sessions go through your server instead of a third party.

17. MeshCentral

MeshCentral (Apache 2.0) is a self-hosted remote management server: remote desktop, terminal, file transfer and device grouping for hundreds of PCs from one web console.

Vulnerability scanning

18. Greenbone Community Edition (OpenVAS)

Greenbone's free Community Edition includes the OpenVAS scanner. It scans your servers and network devices for known vulnerabilities and missing patches, similar to Nessus or Qualys. Ideal for monthly internal vulnerability scans required by ISO 27001 and audits.

Note: Wazuh also has built-in vulnerability detection for machines with the agent installed, so many small teams use Wazuh for endpoints and OpenVAS for network devices.

Password manager, documentation, backup and firewall

• 19. Vaultwarden (AGPL v3): a lightweight, self-hosted server that is compatible with the official Bitwarden apps. Good for storing shared IT passwords securely instead of Excel. (It is an unofficial community project, not made by Bitwarden.)
• 20. BookStack (MIT): a simple wiki for IT documentation: SOPs, runbooks, network diagrams and "how to" guides for the helpdesk.
• 21. UrBackup (AGPL v3): client-server backup for Windows and Linux PCs and servers, with file and image backups.
• 22. OPNsense (BSD 2-Clause): a full open-source firewall and router with VPN, IDS/IPS (Suricata), web filtering and a clean web UI.

Recommended free IT stack for a small company (50 to 300 users)

Need	Tool	Why
Monitoring and alerts	Checkmk Community (or Zabbix)	Fast setup, auto-discovery, modern UI
Security, AD logs, SIEM	Wazuh	Agents + rules + OpenSearch-based dashboard
Helpdesk	osTicket (or GLPI)	Simple, proven, email-to-ticket
Asset management	Snipe-IT	Who has which laptop and licence
Remote support	RustDesk (self-hosted)	Free, private, no licence issues
Passwords and docs	Vaultwarden + BookStack	Secure shared passwords and SOPs

Most of these run happily on a few Linux VMs or with Docker. Start with one tool, get it stable, then add the next.

Before you deploy: 7 things to plan

1. Who will maintain it? Open source is free to download, but someone must install updates, take backups and fix issues.
2. Security first: never expose admin panels (Wazuh, Snipe-IT, osTicket) directly to the internet. Use VPN, HTTPS and strong passwords with MFA where supported.
3. Backups: back up each tool's database and config regularly, and test a restore.
4. Updates: subscribe to each project's release notes; security fixes come often.
5. Sizing: log tools (Wazuh, OpenSearch) need the most disk and RAM. Follow the official hardware guidance for your number of agents and decide log retention (for example 90 days hot, 1 year archive).
6. Integrations: connect tools to Active Directory/LDAP for single sign-on, and send alerts to email or Microsoft Teams.
7. Licence check: licences like AGPL require you to share code changes if you modify the tool and offer it as a service to others. For normal internal company use this is usually not an issue, but check with your legal team for commercial redistribution.

FAQ

Are these open-source IT tools really free?

Yes. The open-source editions have no licence fee and no user limits in most cases. Your costs are the server, storage and the time to set up and maintain them. Many projects also offer paid support or cloud versions.

Which is better, Nagios or Checkmk?

Checkmk grew out of the Nagios world but is much easier to use, with automatic service discovery and browser-based configuration. For new setups, Checkmk Community is usually the better choice. Nagios Core suits admins who want maximum manual control.

Is Checkmk Raw Edition discontinued?

No. In March 2026 it was simply renamed to Checkmk Community. It is still free and 100% open source.

Can I monitor Active Directory logs for free?

Yes. Install Wazuh, enable advanced auditing on your domain controllers, and install the Wazuh agent on each DC. You can then search and alert on events like 4625 (failed logon), 4740 (lockout) and 4728 (user added to a security group) in the Wazuh dashboard.

What is the difference between Wazuh and OpenSearch Dashboards?

OpenSearch Dashboards is a general-purpose interface for searching and visualising data stored in OpenSearch. The Wazuh dashboard is a fork of OpenSearch Dashboards with ready-made security modules, rules and compliance views.

Is osTicket still maintained in 2026?

Yes. osTicket (GPL v2) continues to receive updates. If you want a more modern interface, look at Zammad or GLPI.

Is Snipe-IT free for companies?

Yes. The self-hosted version of Snipe-IT is free under the AGPL v3 licence with no limit on users or assets. Grokability also offers paid hosting and support.

Which open-source tool replaces AnyDesk or TeamViewer?

RustDesk, which you can self-host on your own server, or MeshCentral for managing many devices from a web console.

Final words

You do not need a big budget to run a professional IT setup. Start with the four core tools, monitoring (Checkmk/Nagios/Zabbix), SIEM (Wazuh), helpdesk (osTicket) and asset management (Snipe-IT), and add remote support, IPAM, password management and documentation as your team grows. Learning these tools is also a great skill for your CV: IT admin and SOC job descriptions often mention tools like Zabbix, Wazuh and GLPI.

Related guides: 25 Conditional Access policies every Entra tenant needs, Desktop support engineer interview questions and Redkey USB and ISO 27001 data wiping.

Sources

• Checkmk: Meet the new Checkmk lineup (Raw Edition renamed to Checkmk Community, March 2026)
• Wazuh documentation: capabilities
• Wazuh documentation: configuring log collection (Windows event channels)
• Wazuh dashboard on GitHub (fork of OpenSearch Dashboards, Apache 2.0)
• Snipe-IT project overview (licence, version, features)
• osTicket and open-source helpdesk alternatives 2026 (licences and maintenance status)
• Best open-source monitoring tools in 2026 (Zabbix, Checkmk, Uptime Kuma licences)
• Microsoft Learn: Active Directory events to monitor

Techyami is not affiliated with any of the projects listed. Licences and editions can change; always confirm on the official project website before deploying in production.