The GNS3 toolbar found at the top of the GNS3 GUI, contains groups of icons that allow you to easily perform common tasks. notice that VMnets 2 - 7 are Host-only, and have their own local DHCP servers disabled. That is important!!) We are not discussing the importing of the GNS3 VM in this document; but rather the addition of other virtual machines to GNS3 topologies which may be running in the GNS3 VM or running locally. VMWare Limitations in GNS3 ​ If you selected the Idle-PC finder button (only necessary if no value was detected automatically), GNS3 will calculate a value:

The devices toolbar allows you to add devices to your network topology. You do this by dragging devices from the Toolbar to the GNS3 workspace (explained below). Some appliances are designed to only run in VMware. Also, there are times when you may simply prefer using a desktop VM (and the GUI applications it can provide), instead of using the serial console to work with the VMs CLI in a terminal. Desktop VMs are more responsive in VMware than Qemu, purely due to technical reasons that are beyond the scope of this document. What about VMWare Fusion? ​

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VMware Workstation Players (and VMware Workstation Pro users) can use a script included with GNS3 (named gns3vmnet) to automatically create and configure the additional VMnets necessary. You’ll be prompted which server you’d like to run the image with, but everything except 'Run the IOS router on my local computer' should be greyed out. The GUI of the GNS3 network simulator is straightforward to use. By default, you will get some pre-defined device templates. However, to use different virtual products (i.e., Cisco/Juniper Routers, Switches, Firewalls) on GNS3, you just need to get a binary image of the devices. GNS3 supports virtual routers and switches in the IOU (IOS on Unix) and IOS (Internetworking Operating System) formats. The above image is listing the name of the PC, indicating that you’d like to run this node via the local server. When you create topologies in GNS3 using the all-in-one software GUI client, the devices created need to be hosted and run by a server process. You have a few options for the server part of the software:

In this instance, the both the local server (the name of the PC) and the GNS3-VM are currently up and running. The local server’s resource usage includes more than just what GNS3 itself is using (if you are heavily multitasking while running GNS3, you’ll see that reflected in the resource summary), while the resource usage for the GNS3-VM is only showing what it is currently using.If you will install the GNS3 server on the local system without a virtual machine, select the following components and tools.

The final three buttons are pretty self explanatory. The first magnifying glass (with the plus (+) sign) will zoom in the topology view: The data of the VMware VMs are stored outside GNS3. This mean a topology using a VMware VM will not be portable on a different computer. If you want a portable topology you will need to use Qemu. GNS3 does not support or recommend the use of Qemu images with a local GNS3 installation on Windows or Mac OS X. You should use Qemu images with the GNS3 VM. The recommended Cisco images to use with GNS3 are those from Cisco VIRL (IOSv, IOSvL2, IOS-XRv, ASAv). This images are supported and are actively updated by Cisco. The images support current releases of the Cisco IOS (15.X) and provide the best scale and user experience. Drag and drop the app from the DMG into /Applications. Start the app at least once to register the protocol handlers.Create dynamic network maps for troubleshooting and proof of concept (POC) testing: - Test your networks before you build them to reduce the time it takes to get a production network up and running The Circle, Square, and Line buttons allow you add and arbitrarily change the size/shape and color of those shapes that you add to a topology. In this guide, the Windows operating system is used. The process is similar however for other operating systems such as Mac OS and Linux. No limitation on number of devices supported (the only limitation is your hardware: CPU and memory) Performing that operation varies between antivirus suites, so you’ll need to refer to their relevant documentation to learn how to do this.

This pane will display the servers in use (local, local GNS3-VM, remote), their state (on/off), as well as their current resource usage. Note that the local server includes statistics for more than just GNS3, so if you’re heavily multitasking, that will be reflected in its reported resource usage. GNS3 Console ​ If you are using GNS3 Network Simulator in your Linux machine, you do not need to install and configure an additional Virtual Machine for GNS3. But you can! The main purpose of GNS3 VM is to give Unix Based IOU support to Microsoft Windows. But, in Linux, by default, you have the full support of IOU ( IOS on UNIX). So, you can continue your installation process with the above instruction. If you want to know the total number of interfaces in a router, just type the below command and you will get information about all interfaces. This is the client part of GNS3 and is graphical user interface (GUI). You install the all-in-one software on your local PC (Windows, MAC, Linux) and create your topologies using this software. This is what you usually see show in screenshots such as the following:The GUI is subdivided into several sections: The Workspace, Toolbar, Devices Toolbar, Topology Summary, Servers Summary, and the Console. GNS3 Workspace ​ The Green “Play” button on the GNS3 Toolbar will power on all devices in the topology, while the Yellow “Pause” button will suspend them, and the Red “Stop” button powers everything in the topology down: It connects GNS3 to the host computer's network. It allows the nodes emulated/simulated on GNS3 to communicate with nodes available outside the GNS3. Cisco VIRL is a closer product in comparison to GNS3 allowing network engineers to simulate real world networks in addition to learning Cisco technologies.