Optionally, you can also buy the complete CCNA Routing and Switching (exam 200-125) step by step lab manual guide from the Amazon Kindle Store for the self-study.
We assume you follow the legal license terms.
Note: GNS3 IOS images are subject to copyright of the respective vendors. Using GNS3 is not as difficult as people think. If you have not yet worked with GNS3, we would highly recommend you to visit the following links that will guide you how to download and use GNS3. We assume that you have already downloaded and installed the GNS3 simulator on your system. However, you need to download IOS images for GNS3 before you can perform the hands-on lab exercises. One of the great features of GNS3 simulator is that it allows you to perform real-life 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. 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. Since arranging physical devices, such as Cisco routers and switches is probably not possible for everyone. In order to perform CCNA and CCNP hands-on lab exercises, either you need the physical devices or a simulator.