Answer to Ma_purol: Well, after all these answers, I don't think I have a lot to say. What I would suggest is that you check your computer for running services you don't need (how to do it will depend on your operating system and tools available ). You may want to setup a firewall as well. About the scanning, a firewall discarding every packet sent to your machine would make your machine fairly invisible . Ok, not bullet-proof. You have the proxy option, personally, I don't need it, but you may want to give it a try.. how to do it has already been explained. If you are in a lan, you can hide ips inside the lan using a NAT ( http://www.webopedia.com/TERM/N/NAT.html ). The nat server translates packets within the network, with source address like 192.168.0.x into packets that bear the server's IP instead (this Ip is connected to the Internet). The server tracks connections made, to be sure it will send the answers from servers to the right computers. I think these three would be enough. The other sollutions I can think of are illegal, so I am quite satisfied now. Good luck!
Cantdoright: You're talking about the NAT stuff check the link above. Iptables shows you one way to do it..