Additional Link: Country Block Tutorial
Want to restrict or block someone from certain countries accessing your Joomla web site? Country Block module is the answer.
CountryBlock, a Joomla Module, is designed to offer your maximum flexibility to control where and how to restrict visitors based on their countries. In addition, it can be set as a regular module to display IP, Country and Flag information for the visitor.
Countries are determined by visitors' IP address. To use the tool, publish the module and place it to the places where you want to