Wow, I have spent so many hours troubleshooting GNS3 and getting the dang thing to work properly for years. I used it to get my CCNP and have worked for Amazon for the last 6 years. I now am back trying to buttress my knowledge and I had to find a training platform that was easier than I had experienced in the past. The DYNAMIPS FULL-PACK is AMAZING!. I just started with it but so far it’s been seamless. Just get a VMWare hypervisor. I’m actually using Fusion 11. Install the VM, what ever one you choose, I chose GNS3 because I am so familiar with it. It Just Works. I’m impressed so far. Thanks.