I signed up last night and have been looking around the site for about an hour - I like what I have read so far but maybe there's an easier way to find what I've been looking for.

Is there a decent tutorial for newbies that gives some instructions towards properly sealing down and testing a linux server? I've turned off all non-essential services, but I am still paranoid about running dns, mail and web services.

Is there a consolidated tool I can use to test the security of my linux server? Or to really be safe, is the proper way to learn every possible hacking / DOS tool and try them on myself one by one?

Thanks!