There have been few requests on forums where people wanted to control access to sites based on country from where request originated. We recommended people to use IP restriction module functionality which required people to add IP address ranges of the countries they want to grant or deny access in ipSecurity section. This is easier said than done. There are a number of IP-to-country mapping lists available for free and updated frequently. These lists are usually in CSV format and identify countries (and sometimes even regions in the country) to which a particular IP-range is assigned.