how do i learn how to hack - for security checking

hi all i'm going to connect my server to the internet. b4 i do that, can anyone recommend to me some good firewalls- that's also easy to configure? anyway,how do i check that my server is secure enough? any hints or reference is much appreciated. thanks in advance. tk ===== 0Oo~~:o) Smile! You'r Alive!!! Q:What's peacefulness? A:What's confusion? Peacefulness is the end of confusion. o.0.Oo.o May there be peace in every step we take :o):tk __________________________________________________ Do You Yahoo!? Yahoo! Mail � Free email you can access from anywhere! http://mail.yahoo.com/