This page will take you through the steps to get started with GNS3 in a Windows environment. All of the critical and most important things to know will be covered, but for an in-depth discussion, see other pages. If you use Linux, there is a GNS3 Quick Start Guide for Linux Users in the next page.
Step 1 – Download GNS3
The easiest way to install GNS3 in a Windows environment is to download the all-in-one version. The file is a little under 16 MB in size and will take less than a minute to download on a DSL or cable connection. Dial-up connections will take somewhat longer.
Step 2 – Install GNS3
Find the file you download and double-click on it to begin installing GNS3.
The GNS3 Setup Wizard will begin. Everything else is a matter of clicking on next or agree buttons.
GNS3 depends on several other programs to operate. Those dependencies include WinPCAP, Dynamips and Qemu and these components along with GNS3 are all chosen by default for installation. The default location to install GNS3 is also chosen for you.
Moreover note that if needed, WinPcap Setup Wizard will be launched for you to install it, this dependency is required for GNS3 to communicate with real networks through a physical network internal controller. The installation for WinPcap will begin. However, if you have a previous version of WinPcap on your computer, the wizard will ask to remove the older version and will then install the newer version.
You have now completed the installation of GNS3. Click the Start button, All Programs, GNS3, and then choose GNS3 out of the list of applications installed. You’ll see the main GNS3 window. We’ll discuss its panes in a later step, but first we have to configure the location for a Cisco IOS.
Step 3 – Defining Cisco IOS files
As mentioned earlier, you must provide your own Cisco IOS to use with GNS3 due to licensing issues. GNS3 is meant to be used in a lab environment for testing and learning. Once you have obtained your own copy of a Cisco IOS for one of the supported platforms, you are ready to continue. Supported platforms are Cisco 7200, 3600 series (3620, 3640 and 3660), 3700 series (3725, 3745) and 2600 series (2610 to 2650XM, 2691).
On the Edit menu, choose IOS image and hypervisors. Then under the IOS Images tab, click … and then find your Cisco IOS file and click Open. The file will appear as your Image file. Next, click the drop-down arrow next to Platform and choose the platform that corresponds to your IOS file.
Now click the drop-down arrow next to Model and choose the model corresponding to your IOS file. For now, we’ll accept the default values that remain. However, there is a very important value called the IDLE PC value that we will want to include. We’ll get to that later. Click the Save button and then the Close button. This will return you to the default GNS3 window. It’s time to create our very first simple topology.
