In this guide, I will show you how to successfully install GNS3 using VMware Workstation Pro. This setup is recommended over VirtualBox for better stability. We will cover installing the GUI, setting up the VM, and troubleshooting common virtualization issues in Windows 11.
The first step is to get the main graphical interface running on your local machine.
Navigate to the GNS3 website and download the "All-in-One" installer. Run the installer on your computer.
The installer will prompt you to install additional tools such as Npcap, Wireshark, and Solar-PuTTY. It is generally safe to accept the defaults. However, Npcap is critical as it is required for capturing packets.
Note: If you already have Wireshark or Npcap installed, uncheck them during the process to avoid version conflicts.
To run network appliances efficiently, we need the GNS3 Virtual Machine. We will use VMware Workstation Pro for this, which allows for nested virtualization.
Return to the GNS3 download page and locate the specific download for the GNS3 VM. Ensure you select the version for "VMware Workstation and Fusion".
Open VMware Workstation Pro. Select "Open a Virtual Machine" and locate the .ova file you just downloaded. Import the file using the default settings.
Now we need to link the GUI we installed in Step 1 with the VM we imported in Step 2.
Launch the GNS3 GUI. A Setup Wizard should appear automatically. Select "Run appliances in a virtual machine"; this is the preferred method for stability.
The wizard will ask for the location of your GNS3 VM. Select VMware from the dropdown list. The system should automatically detect the "GNS3 VM" you imported earlier.
You may adjust the vCPU and RAM settings here. A common baseline is 1 vCPU and 2GB+ of RAM, though this depends on your host machine's resources.
To verify that the installation was successful, we should create a simple topology.
Drag a router or switch node from the appliance list into the workspace.
Start the node. If it turns green, the VM is communicating correctly with the GUI, and your installation is complete.
Users on Windows 11 often encounter errors because security features block VMware from using nested virtualization (which is required to run network images inside the VM).
Open your Windows Security settings and navigate to Device Security > Core isolation. Toggle "Memory Integrity" to OFF. You will likely need to reboot your computer after this change.
If the issue persists, you may need to manually disable the hypervisor launch type. Open Command Prompt as an administrator and run the following command:
bcdedit /set hypervisorlaunchtype off
Restart your computer for the changes to take effect.