Below you can download GNS3, a network simulator for making labs or topologies of routers (IOS, JunOS), firewalls (ASA, PIX) and hosts. It is particularly useful for training to Cisco certifications (CCNA, CCNP, CCIP, CCSP, CCVP or CCIE) or Juniper certifications (JNCIA, JNCIS or JNCIE). Thanks to VirtualBox integration, now even system engineers and administrators can take advantage of GNS3 to study Redhat (RHCE, RHCT), Microsoft (MSCE, MSCA), Novell (CLP) and many other vendor certifications.


New users to GNS3, it is recommended to download the all-in-one package below.

Mac OS X



For an installation from the sources, GNS3 requires the following dependencies to be installed: Qt, Python, Sip, and PyQt. Please see the README for more information. Old releases can be downloaded on

Other downloads