Description:

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 March 2003. This database simply
contains IP blocks as keys, and countries as values. This database
should be more complete and accurate than using reverse DNS lookups.
Commercial databases and automatic update services are available from
<http://www.maxmind.com/>.

This library 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.