GNS3 is freely available and open source software that allows users to explore router configurations, design and test their own networks, and study for certification tests, all without spending a dime.

Before virtualization, the only way to learn about networking hands-on was to build expensive labs with physical hardware or pay outrageous training fees. No more.

No Starch Press’ The Book of GNS3 (, shows readers the many ways the software can be used—all without plugging in a single network cable. It’s 272 pages and costs US$39.95. Readers of the book learn how to:

° Build networks of unlimited size and scope using Cisco and non-Cisco technology;

° Add Juniper routers to their projects with VirtualBox and QEMU;

° Connect GNS3’s devices to physical hardware.

Author Jason C. Neumann is an active member of the GNS3 project, supplying code, moderating forums, and beta testing the GNS3 software. He’s a network engineer with more than 20 years of IT networking experience, who holds multiple certifications from Cisco, Juniper, Microsoft, Novell, and VMware.