Overview of Linking to Host OS

You can connect a network device such as a router on the GNS3 project to the host OS that has installed GNS3. Then, you can communicate from the host OS to the router emulated on GNS3. In addition, communication between the external network connected to the host OS and the network emulated by GNS3 is also possible.

This section explains how to link the GNS3 project to the host OS in a Windows environment.

How to link to the host OS

It’s very easy to link your GNS3 project’s network to the host OS. All you have to do is place “Cloud” on your project workspace and set up the link to “Cloud”. When setting up the link to the Cloud, choose an appropriate network interface (network adapter) that is recognized by the host OS.

Figure “Cloud” and link

You can check the network interfaces recognized by the host OS from [Control Panel] > [Network and Internet] > [Network Connections].

図 ネットワークアダプタ
図 ネットワークアダプタ

Notice

OpenConnect Virtual Network Adapter (TAP-Windows Adapter V9) prevent communicating between GNS3 devices and host OS.

Image of the link to the host OS

Let’s think a little bit more about the image of a link when you deploy the “cloud” and set up the link. A connection in the “cloud” is a bridge connection. So it’s easy to think of the “cloud” as just a layer 2 switch. The “Cloud” part can be treated as a single network.

Default state

This image shows that the host OS and the “Ethernet” network interface are connected inside the host when the host is connected to the external network via an “Ethernet” network interface. An IP is running on the host OS and an IP address has been assigned to it. If nothing else, it is independent of the routers on the GNS3 project.

Figure Default GNS project and host OS connection

Link to the host OS

When you place “Cloud” on the GNS3 project workspace and set up a link to “Ethernet”, the host OS and the network devices emulated by GNS3 will be connected to the same Layer 2 switch (“Cloud”). Then, the “Cloud” and the host’s network adapter (Ethernet) will be connected to the “Cloud”. In other words, the “Cloud” will be connected to the external network.

Figure Link to "Cloud".
Figure Link to “Cloud”.

The following article describes a specific example of a router and host OS connection on GNS3.


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