The IP address are assigned to a netuser not based on his location but from the Internet service provider (ISP) from where he gets the net connectivity, which may be different from user to user, if they avail the services of different ISPs.  Even, if the user avails the services of the same ISPs there are no hard & fast rules that the IP addresses necessarily appear "close" to one another in any sense, other than the convenience of the ISP.

The IP address can be tracked from the header of the Email IDs. There are various IP address locator available like http://www.CANCER-FOCUS.com from where one can get information about the ISP address to which the particular IP address belongs. Some additional information may be available that indicates the general area that an IP address might reside, i.e. the location of the country or city, if ever, but nothing more specific than that. Here the help of the ISP is required to pinpoint the location and identity of the user. The ISP that allots the IP address to particular computer knows where the user lives. But the ISP’s would not provide the information to the general public due to the strict privacy policy which they adhere to. Here the role of law enforcement machinery comes into picture. The Police and the courts can, with appropriate cause, direct the ISP that the requisite information with respect to the IP addresses be provided. The Section 91 of Code of Criminal Procedure, 1973 and Section 69 of the Information Technology Act, 2000 makes provision to this effect.