GeoIP is a C library that enables the user to find the country that any IP
address or hostname originates from.  It uses a file based database that is
accurate as of January 2008. This database simply contains IP blocks as keys,
and countries as values. It should be more complete and accurate than using
reverse DNS lookups.

This module can be used to automatically select the geographically closest
mirror, to analyze your web server logs to determine the countries of your
visitors, for credit card fraud detection, and for software export controls.