Download
The open source GeoIP C API includes a free GeoLite Country database. The code is licensed under the LGPL. Download C API now.

A free geolocation database, GeoLite City, is also available.

Install
This API should work on most UNIX and GNU/Linux platforms and is thread-safe.

./configure make make check make install

For installing on Windows, see the READMEwin32.txt file supplied with the distribution.

Usage
This following sample code looks up the country code by IP address:

#include <GeoIP.h> int main (int argc, char *argv[]) { GeoIP * gi; gi = GeoIP_new(GEOIP_STANDARD); printf("code %s\n", GeoIP_country_code_by_name(gi, "yahoo.com")); }

To compile this example, run gcc -lGeoIP example.c.

For additional examples, see test/test-geoip.c and apps/geoiplookup.c.

A FreeBSD Port is available from http://cvsweb.FreeBSD.org/ports/net/GeoIP/