There are virtual environments where you can setup up these devices and purposely take them down to understand what steps are needed to recover. I'm in the process of working on a DR plan for our environment. Once the plan is completed, I am going to have to test it to make sure it works. I'm not going to test it in our production environment, that would be what we call a resume generating event. I'm going go into my home lab, set up a test environment and run through the plan. I'll do that a few times, purposely mistakes so I can have an idea on what to do if something goes wrong. In the scenario I mentioned with a firewall, there is a tool called GNS3 (haven't used it in years) that you could use to gain experience working with network devices. You telling me you set up a network and created multiple subnets to isolate devices using GNS3 or a similar tool tells me more about you than passing a certification.
