GNS3 1.0 was released to the world on October 21st, 2014. I have been using previous versions of GNS3 for some time now to simulate networks and to practice for my Cisco certifications. For those of you who aren’t familiar with GNS3, it is an application that allows you to build networks for free. The caveat there is you need to supply the images for your equipment. GNS3 supports Cisco, Juniper, HP, Arista, Citrix, and Brocade (as specified on their site, gns3.com. You build out a virtual lab which means there is no need to purchase physical hardware.
Before getting started, you’ll need to sign up on GNS3‘s website. Once you have an account. You can download GNS3. Click on the Windows download button to begin.
Once you open the installation file, click through the standard setup screen and agreement until you get to the Choose Components section.
Select all the components you will need – almost everything. SolarWinds is a new application packaged with GNS3. If you already have some of the components installed, such as Wireshark, you can uncheck it.
After completing installation, Start GNS3.
Upon opening GNS3, you will be prompted to save your new project locally or in the cloud. For the purposes of setting up GNS3 I will skip this.
Click on Edit and then Preferences.
Expand Dynamips and select IOS routers.
This is where you must supply your IOS image. I cannot supply these images for you. Click on New to add your image.
Enter the name of the Image and its platform.
Set the amount of RAM to be allocated to IOS.
Select the default adapters you want installed for each new instance of this device.
After you finish, the router will be displayed with its settings.
Click on the General tab to view your settings. Make any changes as you see fit.
The Console applications tab is where you can configure what application is to be used to console into your devices within GNS3.
The Packet capture tab displays your settings for capturing traffic on links between your devices within GNS3. Notice the capture analyzer command using SolarWindows Response Time Viewer.
Click OK to close the Preferences window.
The big window in the middle of GNS3 is your topology view. This is wear you drag and drop devices from the left menu item.
To add a device, click on one of the symbols on the left and drag and drop the IOS image you’ve uploaded to GNS3.
The Topology Summary window will display a list of all your devices. A red orb signifies a device that is off. A green orb means the device is on.
Right click on your device and click on Start to turn on your device. Right click again and select Console to bring up Putty to manage your device.
Happy labbing! Let me know if you have any questions in the comment section below!