Absolutely. Within that playground you can have a distributed wonderland, running VirtualBox, KVM or XEN where you spin up Linux hosts rapidly. Now your playg

Absolutely. Within that playground you can have a distributed wonderland, running VirtualBox, KVM or XEN where you spin up Linux hosts rapidly. Now your playground can start to imitate real life. It sounds like the poster you're replying to need to solidify the fundamentals, before the playground under his/her feet can be experienced. TCP/IP Illustrated, one of many introductory guides to DNS, etc. can be read through. TCP/IP Illustrated Vol 1 is great because of how simple it makes networking feel, and it does so while showing you packet captures (another skill to pick up). Add to that GNS3, which I've seen people use to design and sketch out company networks (just need a Cisco account to download the IOS images). We could go on. The point is that your (free) playground is right under your nose.