There are three methods of querying the GeoIP databases from PHP. The easiest to setup is the Pure PHP API. The setup for the high performance PHP extension and mod_geoip APIs is more advanced.

Pure PHP module
Download pure PHP module. Free GeoLite Country and GeoLite City databases are available.

A port to PHP5 of the PHP API is available from PEAR.

The Pure PHP API is cross-platform, works on Windows as well as Linux, and does not require Apache, nor does it require the C API.

PHP Extension on PECL
Download a PHP extension that allows you to embed the GeoIP C Library inside PHP for improved performance.

Using mod_geoip with PHP
For improved performance, you can access the mod_geoip from PHP. There is a trade-off between performance and ease of installation - the Apache module is faster (benchmark), but the pure PHP module is much easier to install.

The following must be installed to use mod_geoip from PHP.

• GeoIP C Library
• Apache web server
• GeoIP Apache module

Usage
Once mod_geoip is installed, it is easy to use from PHP. Use something like the following:

<% $country_code = apache_note("GEOIP_COUNTRY_CODE"); $country_name = apache_note("GEOIP_COUNTRY_NAME"); %>