How to Install GNS3 IOU on Linux / Ubuntu

To use Cisco L2 and L3 images on GNS3, you need to configure IOU.

Installing GNS3 IOU on Ubuntu

How to Setup GNS3 IOU on Linux / Ubuntu

In order to be able to use Cisco IOU images on Linux systems, we will install GNS3 with IOU support. Before moving on to the installation, let’s briefly talk about what IOU is and what it does.

What is GNS3 IOU?

IOU (IOS on Unix) is a technology that is similar to Dynamips but uses less. IOU images mimic all the features of a particular Cisco IOS technology.

The IOU is also called the Cisco IOU. IOU images do not require hypervisors to emulate Cisco hardware, and IOU images are much more efficient than Dynamips. In GNS3, the use of IOU uses less system memory and CPU.

As a result, using Cisco IOU images on GNS3 allows you to create more specific network topologies.

How to Configure IOU-Supported GNS3 on Linux

First of all, visit Google and download the Cisco IOU L2/L3 images and the file to your computer.

Then, follow the steps below in order to install GNS3 IOU.

Step 1

To install GNS3 on Ubuntu, first open Terminal and perform the following commands.

sudo add-apt-repository ppa:gns3/ppa
sudo apt-get update

sudo add-apt-repository ppa:gns3/ppa

Step 2

After adding GNS3 to the Repository, execute sudo apt-get install gns3-gui to start the installation.

sudo apt-get install gns3-gui

Step 3

Setup reports that it will use 811 MB of additional disk space to install gns3. Type Y (Yes) and press Enter.

Confirm Installation of Dependent Programs

Step 4

Press Enter using the No option to prevent non-superusers from running GNS3.


Step 5

Also, continue with No to prevent non-superusers from performing packet analysis using the Wireshark program.

Wireshark Non-Superusers

Step 6

To start GNS3, type gns3 on the TTerminal and press Enter.

Running the GNS3 Program

Step 7

You can check the version of the network simulator in Help / About.

Verifying GNS3 Version

How to Add Cisco IOU on Ubuntu

After installing GNS3, you need to enable IOU support. Follow the steps below to install Cisco IOU.

Step 1

To install an IOU, open Terminal and perform the following commands in sequence.

sudo dpkg --add-architecture i386
sudo apt-get update
sudo apt-get install gns3-iou

sudo apt-get install gns3-iou

Step 2

To license Cisco IOU images, execute the python3 command and copy the generated code.



Step 3

Open the iourc.txt file and paste the copied code.


Step 4

Rerun GNS3.

Restarting GNS3

Step 5

In the Setup Wizard window, select Run the topologies on my computer and click Next.

Run the topologies on my computer

Step 6

In the local server configuration window, click Next.

Local Server Configuration

Step 7

Once the local server connection is established, click Next.

Local Server Status

Step 8

Close the New Appliance template window by clicking the Cancel button.

New Appliance Template

Step 9

Create a new project on GNS3.

Creating a New Project in GNS3

Step 10

Click Edit / Preferences to license IOU images.

Edit / Preferences

Step 11

In the Preferences window, click IOS on Unix, and then click Browse.

IOS on Unix

Step 12

Navigate to the location where you have located the iourc.txt file, select the file, and click the Open button.


Step 13

After you license the images, click IOU Devices.

IOU Devices

Step 14

Click the New button to add a Cisco IOU image.

IOU Devices

Step 15

Type a name for the IOU image to be added in this window and show the position of the image in the IOU image section. Then click Finish to add the Cisco IOU image.

Name and Image

Step 16

You can review the details you have added to the image below.

Cisco IOU Image

Step 17

Add the Router you have added to the workspace and then run it. Test the functionality of the Cisco IOS software using the show version command.

Show Version

IOU Configuration ⇒ Video

You can watch the video below to install Cisco network simulator software with IOU support. Also, subscribe to our YouTube channel to support us!


In this article, we have examined step by step how to set up GNS3 with IOU support on Linux systems in order to create more specific network topologies. Thanks for following us!


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