Secure Server Rack How DO I Secure A Public Web Server?

How dO I secure a public web server? - secure server rack

I will take this opportunity once again, and then open my web hosting server.

I am in a lot of hacking websites. Hack forums and Shi *.
Well, I do not really know how to protect my site too ..
You have a company, rack safety. Is there anything like that? You can safely back to my server DoS (Denial of Service) attacks?
Plz help meee ..

Thanks