You got Cisco PacketTracer? I'm doing a Cisco course* at the moment and can download it from their site. It's basically a pretty good network simulator where you can add server stacks, routers and PCs and stuff and configure them. Pretty much like an isolated environment to mess around with networking. I can link you with a download if you want it.
* The course I'm currently on is "Cisco IT Essentials", had to do it as part of my apprenticeship. You can actually
read all of the written material for the course without being on the course/having a Cisco account, because they host it all on the Amazon Cloud. I never wrote a ripper to give myself a local copy, or used regex on the local copy to cheat during exams I promise, I'd never do anything like that.