Unfourtanely, the internet is not organized that way.
Instead, it is organized by IP Range Subnets, which are assigned to companies or organizations, not by city. Just because an IP is assigned to a company's administrative or technical office in one city, does not mean it that IP is not used in another. Data can easily be sent across the country or the world, even if the computer you are sending data to is in the office next to you, or house next to you. For example, a trace showed that the data being sent from my office to the high school three blocks down the street from our office (both in san diego), was going all the way to chicago and then to denver to get there!
ISPs connect to each other at "peering points". Sometimes, ISPs do not intersect, and the data has to go farther, sometimes through three or more ISPs to get to the destination one. For example, from my home on road runner, to get to my college (San Diego State, which uses their in-house ISP, TNS, the data must take Road Runner to ATDN (AOL Transit Data Network) then get sent to Level3 and then to CSUNet (California State University), then to SDSU TNS.
To find out what city a computer is in, you can try running a DOS prompt, and type "Tracert <IP Address or NAME>" where <IP Address or name> gets replaced by the name or IP address (e.x. "tracert 130.191.3.100" or "tracert
www.yahoo.com", and it will show all the routers it goes through. Although, the final destiniation could be a router, or the ISP office, sometimes, in which the true location of the individual will not be known. Often, the routers just before will have the names of cities or airport codes in their names. You can also try VisualRoute at
www.visualroute.com.
To see who a block of IP addresses is registered to, go to
www.arin.net (Americas Including US, Canada, Mexico, Brazil, Dominician Republic, Chile, and the Caribbean),
www.ripe.net (Europe including UK, France, Sweden, Swizterland, etc),
www.apnic.net (Asia including China, Japan, Thailand, , Austrialla, New Zealand, etc).
:DAnybody, prompt me a link to a program (programs) which detect or close home ips.