When it comes to network simulators and emulators, everyone has their favorite. In this article, I will be discussing the Graphical Network Simulator (GNS3). See how to install GNS3 on macOS. In subsequent articles, I will be discussing other simulators and emulators listed. Packet Tracer, EVE-NG, Boson NetSim, GNS3 and VIRL. GNS3 is an open-source software that helps in emulating networks using the Cisco Internetwork Operating Systems (IOS). GNS3 enables you to run a Cisco IOS in a virtual environment and serves as a graphical user interface to Dynamics. For some articles I have written on GNS3, please see the following guides Error – Failed to open a session for the virtual machine GNS3 VM and How to make a router function as a switch in GNS3 .

To connect GNS3 connect to the internet on Windows, follow the steps below. For some articles I have written on GNS3, please see the following guides “Error–Failed to open a session for the virtual machine GNS3 VM, how to make a router function as a switch in GNS3, and Graphical Network Simulator:

Step 1: You need to set up a loopback adapter

– Click on the start button,
– Right-click on your computer, click on the device manager, from the dialogue box. Right-click on your Personal Computer name (PC).

Next, you will have to click on add legacy hardware, a welcome wizard appears,
– Select the second tab which says (install the hardware that I manually select from the list (advanced) as shown below.

Select install the hardware that I manually select from the list (advanced)

– Click next.
– From the list, select network adapters as shown in the figure below.

From the dialogue box that appears, select Microsoft
– And on the right pane of the windows select Microsoft Loopback Adapter and
– Click on next, and then finish.
Then restart your computer for the settings to take effect.

Step 2: Open the network and sharing window

– Click on change adapter settings and
– Select the adapter with an internet connection as shown below.
– Right-click on the adapter.
– Click properties, from the dialog box that appears, click on the sharing tab

Select the network adapter you wish to share your internet with (Microsoft Loopback Adapter) and
– Check both boxes as shown in the figure above and click ok.
Note: Ensure you note down the IP address that is assigned to your loopback adapter as you will need it to configure your router interface connecting to the cloud.

Step 3: Go to GNS3

– Drag and drop the cloud image,
– Right-click on the cloud and
– Select the NIO Ethernet as shown in the figure below, and from the tab tree
– Select the Loopback adapter you created and
– Click on add and
– Finally, click on ok.

Select the Loopback adapter you created and click on add

Now GNS3 is fully connected to the internet through the loopback of your network adapter on windows. Next, we will be configuring the router interfaces and their default route.

I hope you found this blog post helpful. If you have any questions, please let me know in the comment session.