learning ethical hacking

Hi All,

Could you please let me know where should i start learning about
network, and web security, I   have been using linux mainly for
several years, windows for a couple of years, and solaris from time to
time, I would like to consolidate  my knoweldge regarding the above
operatings system through a deep exopsure to security. i am thinking
of books, mailing lists, and training courses, i also stumbled once on
a hacker group that would let you joing if you solve a puzzle, some
kind of message encryption, but i do not remmber the site any more,
the main objective is secure a career in network security.

TIA

ant ant

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