What is GNS3? In computing language, an emulator is software or hardware that allows one computer (the host) to act like another computer (the guest). An emulator permits the host to run software or use exterior devices intended for the guest. Graphical Network Simulator 3 (GNS3) is a network software emulator. It allows the amalgamation of virtual and actual devices, used to simulate compound networks. It practices Dynamips emulation to simulate the Cisco IOS. GNS3 is used by many large corporations including Walmart, NASA and AT&T. GNS3 is also widespread for training of network skilled certification assessments. Let's start discussing on how to use GNS3 in Linux OS. You can see in the image that if you've gns3 installed in the virtual OS environment or even on local PC, you can just search for it and open it by clicking on it. When you click on the GNS3, it's gonna pop up new project window. If you've saved project, you c...