In order to perform CCNA and CCNP hands-on lab exercises, either you need the physical devices or a simulator. Since arranging physical devices, such as Cisco routers and switches is probably not possible for everyone. Fortunately, there are various simulators such as Cisco Packet Tracer and GNS3 that you can use to perform CCNA/CCNP and other hands-on lab exercises. In this post, you will get the direct links to download GNS3 IOS images for Cisco routers, ASA, switches, and even for Juniper routers.
One of the great features of GNS3 simulator is that it allows you to perform real-life hands-on lab exercises. However, you need to download IOS images for GNS3 before you can perform the hands-on lab exercises. Click Below link to download GNS3 images:
Download GNS3 IOS Images