I've read in Wikipedia that one of the ways to obtain geolocation information for a given IP is done using DNSBL. The following link is: http://en.wikipedia.org/wiki/Geolocation_software#Data_sources
Could someone explain me how this is done? And in general, what is DNSBL rather than a banning list?
DNSBL is a blacklist/database based on dns. DNS is just your api to get a specific result. Others could be HTTP or a simple local file.
IP needs routing and thus the physical machines doing that are placed in certain locations. Knowing that makes it possible to collect data where the routing points are and thus get to closest location of a certain IP address. (Knowing that there are 5 big co
http://en.wikipedia.org/wiki/Geo_targeting
http://en.wikipedia.org/wiki/LOC_record
http://en.wikipedia.org/wiki/Regional_Internet_registry