What is "footprinting"

n. Any of several techniques for the identification of a member of a class of things, based on some distinguishing feature

Footprinting (also known as reconnaissance) is the technique used for gathering information about computer systems and the entities they belong to. To get this information, a hacker might use various tools and technologies. This information is very useful to a hacker who is trying to crack a whole system.

When used in the computer security lexicon, "Footprinting" generally refers to one of the pre-attack phases; tasks performed prior to doing the actual attack. Some of the tools used for Footprinting are Sam Spade, nslookup, traceroute, Nmap and neotrace.