Are you studying for Cisco Routing or other networking exams and need a way to practice your skills in an actual network setup? Well, GNS3 is here for you! It’s a great network simulator that lets you build complex networks and mimic Cisco’s Router, Switch, or Firewall devices.
In this article, we’ll show you how to set up GNS3 on a Debian 11 or 12 system. Whether you’re using Windows, Linux, or macOS, it can help you design your projects with Cisco devices and get ready for your networking exams.

Credit: Debian
Create and Test Networks Easily with GNS3: Perfect for Network Engineers
GNS3 software is a powerful tool that lets you build complicated network setups and pretend to be Cisco devices like Routers, Switches, or Firewalls using IOS images. With this, you can design your projects just like real networks, which helps you test and double-check your network plans before actually using them in real life.
It works with Windows, Linux, and macOS, so you can use it on whatever computer you have. If you’re using Debian on your computer, you might need to use a terminal to install it. But don’t worry; it’s pretty simple and easy to do.
Installing GNS3 on a Debian PC
If you want to set up and use Cisco network software on Debian 11 or 12, you’ll need to follow a few steps. You can watch our video tutorial or use a set of instructions to help you through it. These steps are essential to make sure the software works well and you can use it without problems.
- To check for new updates for the packages on your Debian system, open the terminal and type the “sudo apt update” command. This will refresh the package lists and show any available upgrades. Doing this helps keep your system safe from potential issues.
sudo apt update
- To get all the stuff you need for GNS3, type a command into the terminal. This command will make sure everything it needs is set up on your computer so you can use it smoothly.
sudo apt install python3-pip python3-pyqt5 python3-pyqt5.qtsvg python3-pyqt5.qtwebsockets qemu qemu-kvm qemu-utils libvirt-clients libvirt-daemon-system virtinst wireshark xtightvncviewer apt-transport-https ca-certificates curl gnupg2 software-properties-common -y
- After you’ve installed Python and the other stuff you need on your computer, you can get GNS3 by typing this command into the terminal: “sudo pip3 install gns3-server gns3-gui”. This command will start the process of downloading and setting it up so you can make complicated network setups for testing and learning.
sudo pip3 install gns3-server gns3-gui
- When you put GNS3 on your computer, you might see a Dynamips error when you try to add a new IOS. To fix this, you need to install the Dynamips package too. Just get the “dynamips.deb” package onto your computer using the wget command.
wget http://ftp.us.debian.org/debian/pool/non-free/d/dynamips/dynamips_0.2.14-1_amd64.deb
- Once you’ve got the “dynamips.deb” package, you can install it by opening the terminal screen and typing this command: “sudo dpkg -i dynamips_0.2.14-1_amd64.deb”. This will start installing Dynamips on your system.
sudo dpkg -i dynamips_0.2.14-1_amd64.deb
- When you put the IOS of an actual Cisco device into GNS3 in Debian after setting it up, you can do a lot more and learn a ton about networking.
How to Add an IOS in Debian
- To change GNS3’s settings, first, open the app. Then, click on the “File” area at the top of the screen. After that, choose “Preferences” from the options. This will open a window where you can modify different things to make it work how you want.
- To put a new IOS router in Dynamips, go to Preferences. Just click on the Dynamips/IOS Routers option, then hit the ‘New’ button on the right side. This lets you make a fresh router for your network simulation.
- Remember, you can pick the IOS image that’ll help you fly high. Just click Browse and confidently point out where the file is. It might be tricky when it’s unzipping but don’t give up.
- To set up your Router image just the way you like it, you’ll need to adjust the name and platform of the image. Also, it’s a good idea to pick the right amount of virtual memory based on how much RAM your computer has, especially for IOS. This will make sure everything works smoothly and does what it’s supposed to do.
- You’ll notice that the FastEthernet interface is already there in the network adapter settings. You can also put in Serial or GigabitEthernet interfaces to the Router.
- Look for the Idle-PC value to make sure the Router runs smoothly, then close the wizard.
- Please make a new project, pick the Router, and move it to the workspace by dragging and dropping it. Once the devices are up and running in the project, you can get to the CLI by clicking on them.
Conclusion
In summary, it is a fantastic tool for network engineers and students who want to practice their skills in a safe virtual space before dealing with real devices. Setting up GNS3 on a Debian 11 or 12 system is easy if you follow a few steps. With this software, you can design and test complex network setups using Cisco devices like Routers, Switches, and Firewalls.
Learning to add IOS images and tweak their settings helps you create a virtual environment that’s just like a real network. This lets you practice and improve your networking skills. So why wait? Get it on your PC now and start exploring the world of network simulation!
If you’re interested in setting it up on your SUSE system, we have a helpful article you might find useful. It provides step-by-step instructions on how to get everything up and running smoothly. Check out How to Install GNS3 on OpenSUSE to learn more!