What is an IP Address ?
Millions of computers and networks connected together form the internet. An IP Address is something that uniquely identifies a computer amongst the millions of computers. This is similar to the geographical address. For eg:- Google New York Chelsea Market Space, 75 Ninth Avenue 2nd and 4th Floors New York, NY 10011 uniquely identifies the address of Google. Similarly, in the internet, an IP Address like 220.127.116.11 uniquely identifies a computer in the internet. However, there is a significant difference between the two.
While the physical geographical address remains constant over a period of time, the IP Address of a particular computer can change every day or remain constant for a particular period of time. However, at any given moment of time, a single IP Address uniquely identifies a computer over the internet. This address is either assigned dynamically when the user connects to the internet through the Internet Service Provider (ISP) or a permanant (static) IP Address is allocated to the customer by the ISP .
What information can be found from an IP Address ?
By performing an IP Lookup, it is possible to estimate the location, ISP, domain name amongst other things from a given IP Address. It is also possible to check if the server is a proxy server. It is also possible to trace e-mail source by performing an IP lookup on the source IP of the email.