Ethical hacking is the process of seeking into computer systems to detect if someone is misusing private information or someone is a potential threat to the security. Hacking can be good as well as bad. But ethical hacking has a positive face. It is performed by smart computer professionals who can prevent non-ethical hackers from stealing confidential information. Ethical hackers ensure security and report all potential vulnerabilities encountered. Ethical hackers are not criminals and can be trusted blindly. They are actually police inspectors and not thieves. These people have strong coding skills and networking skills with which they can track any wrong attempts and threats. These people also invent anti-viruses. Various types of testing is performed to evaluate system security. Some common testing types include Remote network, local network, social engineering and physical entry.Various user types are identified which access the system that they are valid user or an outsider with negative intentions.