etwork configuration question for ADSL Connection .

Hi falks, Just in few words, and a quick question: I'd like to know how can be made an ADSL Internet connection and a safe one ? I means firewall for example. And what system should be activated to make this works fine. What tools should be used to checks the Internet attack, connection, and so on ? And last but not least, how can we get an Internet link from home to the office so that windows client system at home should get connection to the office server, and get a good protection from piracy. Any link, or documentation are welcome. Thanks for your help. Regards