hi
i am a newbie to linux world. and i installed fedora core 3 as Workstation. including webservers, database.

and i would like to get into the grasp of security, so i would like to penetrate into my system(likie a real hacker would), so i will know what needs to be done in fixing those holess..

I would strongly suggest starting your research with UnSpawn's truely excellent security references thread

get a firewall (i use firestarter, http://www.fs-security.com/ ). that is proboly one of the best things to do. if you run web services from your comp then the biggest holes you will have will come from there. stay up on the updates of those and make sure you have them configured properly.

this is a link to two sites that scan your ip address for open ports and other things. it will give you an idea where you stand.
http://www.fs-security.com/docs/faq.php#testing

nmap is anoter tool where you can test you system for its network secruity.
http://www.insecure.org/nmap/
if you use firestarter though it is a waste to use because firestarter will let everything from nmap throuh because of the way it is set up. (firestarter allows replies from requests made from your computer.)

hope that helps some. there is a bit more to do but that is what i do.

thanks guys!
atleast its a start..