Introduction

Get to know your GNS3 Graphical User Interface (GUI)

On first start up

Screen Layout

GNS3 Workspace

GNS3 Toolbar

Create your topology

Last updated
June 12, 2017

Contributors
David Bombal
Julien Duponchelle
Ricar Ganancial
Edit this Article
Last updated
June 12, 2017

Contributors
David Bombal
Julien Duponchelle
Ricar Ganancial
Edit this Article

Your First GNS3 Topology

Introduction

This document explains how to configure a simple GNS3 topology which consists of two Virtual PC Simulator (VPCS) devices.This is a simple way to test your GNS3 installation and build your first topology.

VPCS PCs are installed by default as part of the GNS3 installation on Windows and Mac OS.

NOTEThis document assumes that you already have GNS3 installed and have VPCS installed (default on Windows and Mac OS).

Get to know your GNS3 Graphical User Interface (GUI)

On first start up

When you first start GNS3, you will be prompted to create a new project:

Name the project as desired and then click OK:

Screen Layout

The following figure shows a screenshot of the GNS graphical user interface which we will quickly discuss so you know some of the terminology used:

GNS3 Workspace

The GNS3 workspace is the area of GNS3 where you create topologies by adding devices and links:

GNS3 Toolbar

The GNS3 toolbar is found at the top of the GNS3 GUI and contains groups of icons that allow you to easily perform common tasks:

                                                             

The toolbar groups icons into specific functions or features. This gives you a simple way of getting things done.

Devices Toolbar

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).

                                                             

The devices toolbar is grouped into different types by default:

Routers

Switches

End Devices

Security Devices

All Devices

Add a link

You will find both simulated devices as well as emulated devices in the various device groupings.

Create your topology

To create a new GNS3 topology, click the Browse End Devices button on the Devices Toolbar:

The toolbar will expand to show available devices of that type. In this example VPCS is one of the available devices:

Drag and drop the VPCS node (device) to the GNS3 Workspace. An instance of the node becomes available in the Workspace. In this example a new VPCS with the name PC1 is now available:

Drag and drop the VPCS node again into the GNS3 Workspace. In this example, another VPCS was added to the GNS3 workspace (PC2):

        

Click the Browse End Devices button on the Devices Toolbar to collapse the group:

Click the Add a Link button to start adding links to your topology. The mouse cursor will change to indicate that links can be added:

Click on PC1 in your topology to display available interfaces. In this example Ethernet0 is available (this is device dependant):

Click Ethernet0 on PC1 and then select PC2:

Select Ethernet0 on R2 to complete the connection:

Click the Add a Link button to stop adding links. The mouse cursor will change back to normal to indicate that you have stopped adding links:

Click the Show/Hide interface labels button on the GNS3 Toolbar to display interface labels in your topology:

You are now ready to power on your network devices. Click the Start/Resume button on the GNS3 Toolbar to start up your network devices:

GNS3 indicates that the devices have been powered on by turning the interface connectors from red to green. This can also be seen in the Topology Summary:

You are now ready to configure your devices. Click the Console connect to all devices button on the GNS3 Toolbar to open a connection to every device in the topology:

A console connection is opened to every device in the topology

Configure your PCs with IP addresses and default gateways as follows (a default gateway is configured in this example but is not used):

PC1> ip 10.1.1.1 255.255.255.0 10.1.1.254

PC2> ip 10.1.1.2 255.255.255.0 10.1.1.254

PC1 should now be able to ping PC2 (use the key sequence Ctrl-C to stop the ping):

PC1> ping 10.1.1.2
84 bytes from 10.1.1.2 icmp_seq=1 ttl=64 time=0.098 ms
84 bytes from 10.1.1.2 icmp_seq=2 ttl=64 time=0.209 ms
84 bytes from 10.1.1.2 icmp_seq=3 ttl=64 time=0.197 ms
^C
PC1>

Result Pings succeed.

To save your PC configurations use the save command:

PC1> save
Saving startup configuration to startup.vpc
.  done
PC1>

PC2> save
Saving startup configuration to startup.vpc
.  done
PC2>

        

Congratulations! You have configured a basic GNS3 topology. From here on, you can create much more complex topologies and test and learn various technologies such as OSPF, EIGRP, BGP, STP and many others.