19 May 09 GNS3 – Graphical Network Simulator

“GNS3 is a graphical network simulator that allows simulation of complex networks.”

I was recently pointed in the direction of this app as a pretty nice graphical interface to the Dynamips / Dynagen router simulation. It still uses Dynamips / Dynagen underneath, along with Pemu (a Cisco PIX firewall emulator based on Qemu), but allows you to do graphically what you normally have to do using textual config files.

The interface is really nice and you can drag and drop in routers, create links between them, and start and stop them through the GUI. Theres no real difference from what I can see in performance etc, so many people would just turn a blind eye and figure, “Why bother, the config files are handy enough”, but it does mean you don’t have to bother with the configuration for the most part, and can just concentrate on the actual task at hand.

And the best news is it’s packaged for Ubuntu! I’m sure this is the case for other distro’s too but I haven’t checked. So all you need to do is:

sudo apt-get install gns3

You can check the documentation etc out at: http://www.gns3.net/