Sep 01

How to configure VirtualBox adapters for your GNS3 VM with GNS3 GUI.

How to configure VirtualBox adapters for your GNS3 VM with GNS3 GUI.

Perfect! Here’s a step-by-step guide to configure VirtualBox adapters for your GNS3 VM so everything communicates properly with your host and GNS3 GUI.

Step 1: Open VirtualBox Settings for GNS3 VM

  1. Launch VirtualBox.
  2. Select your GNS3 VM → click Settings → Network.

Step 2: Configure Adapter 1 (Host-Only)

  • Purpose: Allows GNS3 GUI on your host to talk to the GNS3 VM.
  1. Enable Adapter 1 → attach to Host-Only Adapter.
  2. Choose the default vboxnet0 (Windows) or whatever host-only adapter exists.
  3. Leave Promiscuous Mode as Deny.
  4. Adapter Type: Intel PRO/1000 MT Desktop (default works).

This is the key adapter — without it, GNS3 GUI cannot control VMs or routers.

Step 3: Configure Adapter 2 (NAT for Internet)

  • Purpose: Gives the GNS3 VM internet access (downloads, updates).
  1. Enable Adapter 2 → attach to NAT.
  2. Leave default settings.

Optional: You can also configure a third adapter as Bridged if you want your labs to access your physical network.

Step 4: Boot the GNS3 VM

  1. Start the VM.
  2. On the console, you should see messages like:

GNS3 VM is running

IP: 192.168.56.101

This IP is your Host-Only network IP (vboxnet0).

Step 5: Point GNS3 GUI to the VM

  1. Open GNS3 → Edit → Preferences → GNS3 VM.
  2. Tick Enable the GNS3 VM.
  3. Set Virtualization Platform = VirtualBox.
  4. Select your imported GNS3 VM.
  5. Click Test Settings → it should show Connection successful.

Step 6: Verify in GNS3

  • Drag a router or switch into a project and start it.
  • It should run inside the GNS3 VM, not on your host.
  • You can check CPU usage in VirtualBox — the VM will be active.

✅ Quick Tips

  • Always start GNS3 VM before opening GNS3 GUI.
  • Use Host-Only adapter for VM-GUI communication.
  • Use NAT adapter for internet access in the VM.
  • Don’t manually install software inside the VM unless you know what it affects — GNS3 VM comes preconfigured.

If you want, I can make a small visual diagram showing Adapter 1 (Host-Only) and Adapter 2 (NAT) and how traffic flows so it’s easier to remember.

Do you want me to make that diagram?

Ref: Internet/AI Tools/OpenAI/ChatGPT and Similar

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