GNS3

6.9easy start · #9 of 31
in Network Testing Software

Free to practise onyes
Free trialnot on record
Well documentedyes
Runs where you workyes

Runs on Linux, Mac, self-hosted, Web, Windows.

GNS3 is ranked #9 of 31 in network testing software on The Geeks Club. It runs on Linux, macOS, Self-hosted, Web, Windows. There is a free plan.

GNS3 plans and pricing

All plans

GNS3 Free Open source · no monthly or yearly license fees · device count limited by available CPU and memory docs.gns3.com · 29 Sept 2026

Compared on network testing software

Free plan: Yes
Simulation model: hybrid
Real-time emulation: Yes
Hardware-in-the-loop: Yes
Deployment options: desktop
Automation API: Yes

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The record

Purpose: GNS3 lets network engineers emulate, configure, test, and troubleshoot virtual and real networks.
Open source: GNS3 is open source software that users can download and use for free.
Architecture: GNS3 consists of a graphical all-in-one client and a virtual machine, with local or remote server options.
Multi-vendor support: GNS3 supports devices and appliances from multiple network vendors, including Cisco, Brocade, Cumulus Linux, and HPE.
Emulation and simulation: GNS3 supports both emulated devices running actual images and simulated devices such as its built-in layer 2 switch.
Integrations: GNS3 supports Docker instances, QEMU-based appliances, hypervisors including VMware, VirtualBox and Hyper-V, and connections to real networks.
Appliance marketplace: The GNS3 Marketplace provides preconfigured appliance templates that use recommended settings and are tested by GNS3.
Cisco image requirement: Users must provide their own Cisco IOS images; GNS3 says it cannot provide them.
Security: GNS3 documentation says a GNS3 server has no authentication enabled by default and should be restricted at the network level.
Who it is for: GNS3 is used for networking education and certification practice, proof of concepts, demonstrations, and interoperability testing.
Scale limit: GNS3 does not limit the number of supported devices by license; the practical limit is the host computer’s CPU and memory.
Support: GNS3 points users to its documentation and community for help, questions, and bug reports.
Platform requirements: The documentation lists Windows, macOS, and Linux, and recommends the GNS3 VM for most Windows and macOS setups and complex topologies.
Price from: Free

Where it ranks on The Geeks Club

Best Network Testing Software in 2026#9 of 31
Best Network Simulation Software in 2026#9 of 29

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Sources

docs.gns3.com/docs· checked 29 Sept 2026
docs.gns3.com/docs/using-gns3/beginners/install-from-· checked 29 Sept 2026
docs.gns3.com/docs/getting-started/installation/esxi· checked 29 Sept 2026