Reliability of my designed security

Since I will be rolling out a network, I would like to seek some technical info from you guys.

I have secured my LAN simulator (LAN laboratory)with all my knowledge . I believe it was secured. Tested it with softwares such as port scanner, netbios and etc. and it worked fine.

May some of you out there who could advise me to test my network thoroughly. Please inform me of how do you test your network security.

I am using w2k server with w2k pro clients, How can i hack my server? can youshow me some of those complex tricks.

Don’t worry I am applying this for edu-tainment as well as helping me with my job.