As VoG™ & Indigo 1 say , why on Earth would you want to do that ? If it is hackers you are worried about getting into open ports etc then get a Firewall if you haven't already got one. Heres a link to a free firewall click here follow the links on the left to free edition/download.
I use Norton Internet Security 2004.I ran the on-line security test which identified some open ports which it said were possible points of intrusion, so it seems logical to a non-expert to close them. Isn't it logical?
NIS does include a firewall. I haven't checked with another site. Port 23 (Telnet) and 1025 (Unused Windows services Block) are said to be open. The test program gives the impression that they shouldn't be but it's all a mystery to me. I'm beginning to think that perhaps it isn't worth the bother.
I ran the NIS security tests as well and it said some of my ports were open despite the fact that i have NIS 2004 all updated etc I have just run another test at click here at it came up as everything secure.