The GNS3 network simulator program can be installed on Windows operating systems as well as easily downloaded, installed, and used on Linux-based systems.
How to Install GNS3 2.2.18 on Ubuntu 20.10
With the GNS3 (Graphical Network Simulator 3) program, you can create more specific network topologies and run and use these devices virtually with GNS3 on your computer without the need to purchase network products such as Cisco Router and Switch.
We have previously installed the GNS3 network simulator program on the Windows operating system. While installing GNS3 on the Windows platform, we proceed with graphical steps.
On the Ubuntu operating system, applications are usually installed using the terminal. In Linux systems, you must define the repo addresses of a program. And so, sometimes setting up a program can be time-consuming and complicated.
To install Cisco simulator software on your Linux / Ubuntu 20.10 (Groovy Gorilla) distribution, follow the steps below in order.
Open Terminal by pressing Ctrl + Alt + T keys together on the Ubuntu desktop. To add GNS3 to the Repository, type the following command in Terminal and press Enter.
sudo add-apt-repository ppa:gns3/ppa
To add the repo address of the GNS3 software, enter your system’s root password and then press the Enter key. If you want to cancel this process, as you can see in the terminal, press the Ctrl + C keys together.
To check the current versions of the programs installed on your Linux / Ubuntu system, type the sudo apt-get update command and press Enter.
sudo apt update
After checking the versions of installed programs, execute the apt list –upgradable command to see which programs will be upgraded. If you want to continue the update process immediately, execute the sudo apt upgrade command.
As you can see in the image below, some services running in the background block the process during the update. Check the ID numbers of the conflicting services, ie processes, on your system as follows and then execute the sudo kill -9 (Process ID) command on the terminal to terminate this process.
sudo apt upgrade
sudo kill -9
When you apply the sudo apt upgrade command again, if you get the “dpkg was interrupted” error, execute the “sudo dpkg –configure -a” command as stated in the terminal. Then start the update again.
sudo dpkg --configure -a
After applying the necessary commands, press the Y key and then Enter to start updating the applications running on your system.
Update time may vary depending on your Ubuntu distribution and installed applications. After completing this process, execute the command “sudo apt install gns3-server gns3-gui” in the terminal to install the GNS3 simulator software.
sudo apt install gns3-server gns3-gui
Dependent packages that require the simulator program to work properly on Ubuntu will be installed. Press Y then Enter to confirm the installation of all specified packages in the terminal.
Don’t forget to check your connection as dependent packages for GNS3 will be downloaded from the Internet. At the last stage of the installation, when the Wireshark program is being installed, when you encounter the Configuring ubridge window, press Enter on the Yes option to allow non-superusers users to run this software.
Likewise, press Enter on the Yes option to allow non-superusers members to perform packet analysis on the network with the Wireshark program.
After successfully completing the GNS3 setup, run the program from the applications panel.
After running the GNS3 simulator, a Setup Wizard window will appear. You can close this window or proceed to view and verify localhost settings.
In the Setup Wizard window, select “Run appliances on my local computer” and then click the Next button.
Continue without changing the default settings in the local server configuration window. If there is another application in your system that may conflict with GNS3, specify another value in the Port section.
In the local server status window, you can see that the Localhost service is not conflicting with another application and is running smoothly. Continue by clicking Next in the service verification window.
The summary window shows you that the GNS3 simulator software is running locally. Click Finish to close this window and go to the next step.
Now you need to add a Router IOS image to the Cisco simulator program and test it. To add a new IOS to the program, go to File / Preferences from the menu.
Click on the Dynamips / IOS Router tab and then the New button.
In the New IOS Router Template window, click the Browse button to specify the location of the IOS image.
Select the “c7200-adventerprisek9-mz.152-4.M7.bin” file that you downloaded to your desktop or my documents location and click the Open button to add the IOS image.
Answer Yes to the question of Would you like to decompress this IOS image and continue.
After selecting the Router 7200 image, click Next.
In the Name and Platform window, you can change the name of the device you added and configure the platform type. Leave the settings here as default and click Next.
In the Memory window, you can increase or decrease the memory of the Router device you will run. If you have a high-performance desktop or laptop computer, you can increase the memory a little more.
In the Network Adapters window, you can add FastEthernet, GigabitEthernet, or Serial Interface to the slots of the Router, or you can only use the C7200-IO-FE (FastEthernet) network card by default.
In the Idle-PC window, click the Idle-PC Finder button to automatically set a value to prevent the Router or Switch network devices from using your computer’s processor 100%.
If you get the following error while specifying the idle-PC value, just click OK and continue adding IOS without specifying a value.
Error: Could not send Dynamips command 'vm get_status "AUTOIDLEPC"' to localhost:54121: Connection lost, process running: False
NOTE: The error mentioned above is due to the GNS3 software’s Dynamips incompatibility on Ubuntu 64-Bit.
Close the IOS add window.
Now click on File / New Blank Project to create a new project or press CTRL + N keys together for a faster process.
Determine the file names you can remember for the network projects you will create. If you create new projects for testing purposes, you can delete them later and create free space on your computer’s disk.
When you want to run the Router you added, you may get the following error this time. As we mentioned above, these errors are caused by the Ubuntu Dynamips error. We did not encounter such errors in older distributions, but we shared the solution with you without waiting for new versions to fix this error in new versions.
Dynamips hypervisor process has stopped, return code: -11
C7200 'Ghost': generic_nvram_extract_config: Unknown error -61605
To resolve the Ubuntu Dynamips error, open the terminal on the desktop or any other location, and then execute the command “sudo dpkg –add-architecture i386” to enable 32 Bit architecture on your system.
sudo dpkg --add-architecture i386
After enabling the 32 Bit architecture, execute the command “sudo apt install libc6-dev-i386” in the terminal and press the Y key and then Enter to confirm the installation of the additional packages.
sudo apt install libc6-dev-i386
Likewise, run “sudo apt install libelf-dev:i386 libpcap0.8-dev:i386” to install additional packages to fix the Dynamips error.
After installing the dependent packages required by the 32 Bit architecture for GNS3, you need to download and install the i386 package to ensure Dynamips can run smoothly. To download and install the Dynamips i386 package, execute the commands below.
NOTE: In the new version of Ubuntu, we have fixed a common error in the simulator program commonly used by users preparing for Cisco exams. It took two business days to fix this error. Please do not imitate our content and do not hesitate to cite it as a source.
After completing the Dynamips 32 Bit setup, open GNS3 again and create a new project and add the Router you added to the workspace and run it.
As you can see in the Topology Summary section, the Router started working without any problems.
Double click on the router to open the CLI prompt and execute a simple command “show version” to test it.