I'm about to start studying for my CCNA, and eventually CCSP exams. I know that the Linksys (cisco) home routers run on some flav of linux, but I know the professional stuff runs on Cisco IOS. I was wondering, is IOS just another flavor of linux, with switch and router specific commands and or software? And if it is, can you get a distro of it, or a virtual distro, or SOMETHING that'll allow you to practice at home?

I've concidered buying a managed switch off of ebay, but I'm not educated enough yet to know what to purchase. There was a nice firewall for a decent price, but right now I'll just be studying routers and switches for my CCNA, correct? Or, if the firewall has all the same commands for routers/switches, plus some for the firewall, then I might purchase the firewall anyways.

Please advise me, I'm really excited to start learning some new, that is in such demand.

I appreciate it,
Michael

for your ccna you have enough with a cisco 1500 and you can get if for less that 50 bucks. You will be studying basically old routers and switches and basic stuff, some VLANs too I think that is the most advance topic. Anyways you won't have enough to learn the whole ccna with only one router or switch, you will be better off with an online lab. This site is great and cheap www.cconlinelabs.com and the owner Tony Scraffran is a CCIE and always ready to help you out. Off course if you have some money to spend you can buy 3 or 4 cisco 1500 and interconnect them and do almost all the exam requires you to learn.

IOS is not Linux, no. it's a bespoke operating system written by Cisco from scratch. it has similarilites, but it is very very different in usage and operation.

There are plenty of online lab sites available, although i've never used them. also plenty of products like routersim which can build virtual onscreen networks.

if you do want to invest in some hardware, try something like a Catalyst 2950 switch. they're fairly low end, but still in production, so are totally up to date in terms of functionality you'll want from a cisco box. these don't route at all though, if you wanted to do somethign like then, try a 3550 or similar, which will route, switch and also contain access lists and things, fo the security side.

Catalyst switches and IOS routers are very similar. PIX firewalls are substantially different though, and run a kinda crude hack of the PIXOS code to make it behave a bit like IOS, but it's a long way of being totally familiar to those with IOS knowledge.