How to download, install and get working
Connect to physical devices
How to save and restore configurations in GNS3
How to set up switching in GNS3

What is GNS3 ?

GNS3 is a FREE graphical network simulator that allows simulation of complex networks without the need to purchase network hardware.

In the past, you would have had to spend lots of money on purchasing network equipment to practice labs – now with GNS3, you don’t. GNS3 emulates the hardware of various devices on your computer.

Technical overview - to allow complete simulations, GNS3 uses Dynamips, the core program that allows Cisco IOS emulation. GNS3 also uses dynagen, a text-based front-end for Dynamips; and Qemu, a generic and open source machine emulator and virtualizer. GNS3 is an excellent complementary tool to real labs for network engineers, administrators and people wanting to pass certifications such as CCNA, CCNP, CCIP, CCIE, JNCIA, JNCIS, JNCIE. It can also be used to experiment features of Cisco IOS, Juniper JunOS or to check configurations that need to be deployed later on real routers. This project is an open source, free program that may be used on multiple operating systems, including Windows, Linux, and MacOS X.

FAQs

Is GNS free?

a. Yes, GNS3 is an open source, free program that may be used on multiple operating systems, including Windows, Linux, and MacOS X

Where do I start?

View the videos above to get started and download our GNS3 KickStarter Pack: http://www.ConfigureTerminal.com/software/GNS3.zip

Does GNS3 include everything?

No, users have to provide their own IOS/IPS/PIX/ASA/JunOS to use with GNS3. GNS3 does not include IOS images - these are copyrighted and are the property of Cisco Systems and other copyright holders.

You can download an IOS from www.cisco.com. You will need to log in and you will need the correct rights to download.

You can also look elsewhere and we do not recommend or condone this. Be aware that IOS files are available online, but you may be breaking copyright regulations downloading these.
Please do not ask us to provide you with an IOS.

Here is a link explaining this – use at your own risk: Cisco Forums: https://supportforums.cisco.com/thread/2002657 Other: http://www.blindhog.net/gns3-how-to-find-pix-images-pix-serial-numbers-and-ios-images-using-google/

Can you give me an IOS?

No, users have to provide their own IOS/IPS/PIX/ASA/JunOS to use with GNS3. GNS3 does not include IOS images - these are copyrighted and are the property of Cisco Systems and other copyright holders.

You can download an IOS from www.cisco.com. You will need to log in and you will need the correct rights to download.

You can also look elsewhere and we do not recommend or condone this. Be aware that IOS files are available online, but you may be breaking copyright regulations downloading these.
Please do not ask us to provide you with an IOS.

Here is a link explaining this – use at your own risk: Cisco Forums: https://supportforums.cisco.com/thread/2002657 Other: http://www.blindhog.net/gns3-how-to-find-pix-images-pix-serial-numbers-and-ios-images-using-google/

Does GNS3 support switching

Partly – by using an EtherSwitch card in a router, switching platforms may also be emulated. This however is limited, but should be enough for CCNA studies.

Free Download

Download GNS3:

Download our kickstart guide: