I'm trying to self-learn the following topics on Linux (preferably Fedora):
Network programming (using sockets API), especially across proxies and firewalls
Proxies (of various kinds like transparent, http, socks...),
Firewalls (iptables) and 'basic' Linux security
Network admininstration power tools: nc, socat (with all its options), ssh, openssl, etc
Now, I know that, ideally, it would be best if I had 'enough' number of physical nodes and physical network equipment (routers, switches, etc) for this self-learning exercise. But, obviously, don't have the budget or the physical space, nor want to be wasteful -- especially, when things could perhaps be simulated/emulated in a Linux environment.
I have got one personal workstation, which is a single-homed Fedora desktop with 4GB memory, 200+ GB disk, and a 4-core CPU. I may be able to get 3 to 4 additional low-end Fedora workstations. But all of these -- including mine -- will always remain strictly behind our corporate firewall :-(
Now, I know I could use VirtualBox-based virtual nodes, but don't know if there are any better alternatives disk- and memory- footprint-wise.
Would you be able to give me some tips or suggestions on how to get started setting up this little budget- and space-constrained 'virtual lab' of mine? For example, how would I create virtual routers?
Has someone attempted this sort of thing before: namely, creating a virtual network lab behind a corporate firewall for learning/development/testing purposes?
I hope my question is not vague or too open-ended. Basically, right now, I don't know how to best leverage the Linux environment and the various 'goodies' it comes with, and buying physical devices only when it is absolutely necessary.