These are older images from physical MIPS-based routers (e.g., 3725, 7200). They are lightweight but lack modern features like advanced Layer 2 switching. Cisco IOU/IOL (IOS on Unix/Linux):

IOU (IOS on Unix) is faster for L2 switching:

A: Yes, with CSR1000v (vEdge) and vManage images, but those require a Viptela/Cisco license.

Last updated: October 2025. This guide is for educational purposes. The author does not condone piracy. Always respect software licenses.

These are versions of IOS compiled to run natively on Linux, making them extremely fast and resource-efficient for large topologies. QEMU/KVM Images:

A "full pack" refers to a curated collection of ready-to-use GNS3 images—including routers, switches, firewalls, and host OS appliances—that allows you to simulate an enterprise network without hunting for individual files.

| Source | Content | Cost | |--------|---------|------| | (marketplace.gns3.com) | Official appliances (Ubuntu, VyOS, Arista vEOS) | Free | | Cisco CML Personal | IOSv, IOSvL2, ASAv, NX-OSv, CSR1000v | $199/year | | EVE-NG Community (export to GNS3) | Similar to CML but community-supported images | Free (but BYO images) | | VulHub / Docker Hub | Pre-built vulnerable targets (Metasploitable, Kali) | Free | | Your old physical router | Use tftp to back up your own IOS image (legal for backup) | Already owned |

Assuming you have obtained a legitimate bundle (e.g., extracted from CML or personal routers), here is the professional method.

Download only images you own legally. If a "full pack" contains files you haven’t purchased, you are pirating.

GNS3 is a powerful tool, but with great power comes great responsibility. Respect software licensing, and you’ll build skills that lead to a real networking career—not just a lab full of pirated images.

: Essential virtualized versions like IOSv (Router) and IOSvL2 (Switch), which support modern Layer 2 and Layer 3 features.