Creating an IOS router template using the GNS3 VM server

This section describes the procedure for creating an IOS router template using the GNS3 VM server. Except for the use of the GNS3 VM server as a server, the procedure is almost the same as that for creating a template on the local server. In addition, an IOS image file of the actual router is required beforehand, as in the case of creating a template on the local server.

Step1:Prepare the IOS image file

Save the IOS image file in the local storage beforehand; Cisco 3640 series IOS is relatively easy to obtain and use on GNS3.

Step2:Open [Preferences]

Start GNS3 and click [Edit] – [Preferences] to open the [Preferences] window.


Open the Create IOS Router Template screen.

Select “Run this IOS router on the GNS3 VM” as “Server” and click “Next” to continue.

Step4:Create an IOS router template

From the Create IOS Router Template screen, specify the necessary information to create an IOS router template.

Path of the IOS image file

Check [New Image] and select the IOS image file to be used for the template from [Browse]. The selected image file will be uploaded to the GNS3 VM. Click [Next] to continue.

Note that when the IOS file is downloaded from the actual router, it is a “.bin” file. When you specify the “.bin” file, the following dialog box will appear. Click “Yes” to extract the file into an “.image” file.

Template name

The default name of the router template is the platform name, such as “c3640”. Specify the name of the template if necessary; it is useful to know the feature set and version of IOS.

RAM size

Determine the amount of RAM for the IOS router you want to emulate; there is a link to Feature Navigator to find out the amount of RAM required for the IOS you want to use.


Select the module to be installed in the slot of the router. You can also install a WIC if necessary.


Specify the Idle-pc. Click [Idle-PC finder] to measure the appropriate Idle-pc value. When the [Idle-PC finder] has measured the appropriate value, click [Finish] to complete the creation of the IOS router template.

Step5:Verify the IOS router template

Verify the contents of the IOS router template you have created.