[This article is taken from CEH Ethical Hacker Exam Prep: Understanding Footprinting and Scanning by Michael Gregg]

Footprinting and Scanning is the first basis of hacking. Information gathering has many phases like profiling your target. Whois, ARIN can reveal public information of a domain that can be leveraged further. Traceroute and mail tracking can be used to target specific IP and later for spoofing. Nslookup can reveal specific users and zone transfers can compromise DNS security. Footprinting is necessary to systematically and methodically ensure that all pieces of information related to the aforementioned technologies are identified.