This is part of an email I sent to a security mailing list to which I subscribe, but really, the answer applies to any walk of life. The question is, "How do I get started?"
Really though, the answer to "how do I get started in network security" is the same as it is to virtually any hobby or career: just dive in and start doing it. You'll know you're doing it right when you're learning stuff. You'll know you're doing it wrong if you're not having fun. If you're unwilling or unable to just grab some hardware and start hacking, this area is not for you - the same can be said for any skill. If that sort of thing doesn't appeal to you, then this sort of thing will not appeal to you, and you're wanting to get into it for the wrong reasons, which never ends well. People with skills are rarely willing to just braindump what they know. It's a lot of work for honestly very little return. If you want to learn skills from others, best way to do it is to poke at something a bit, then when you get stuck ask somebody else. Say "I'm trying to do X and I tried Y and Z but they didn't work, here's what happened... any ideas?" Hopefully they'll know, will give you some hints, and that will be sufficient, then off you go again til you get stuck again. If you get really stuck, back up, go around, try something else for a while, get some fresh perspective. There's no magic bullet, no set of books you can read that will make you an expert at anything, and security work is no exception. The secret is putting in the time and effort; that's all, that's it.