What is an IP Address ?
Every computer on the internet is assigned a unique IP Address in the format a.b.c.d where a,b,c and d can take the values from 0 to 255. An example of an IP Address is 213.22.124.8 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.