GeoIPgen is a country-to-IPs generator. It’s a geographic IP generator for IPv4 networks that uses the MaxMind GeoLite Country database.
Geoipgen is the first published software that uses a geographic ip database in reverse to translate from country-to-IPs instead of the usual use of IP-to-country to produce the complete set of IP addresses for a country. Previously software has generated IP address ranges so that entire countries can be blocked by a firewall and the technique used by geoipgen has been discussed before by the GNUcitizen researchers.
Downlaod Here :: GeoIPgen v0.4 (for Linux)
Tutorial & Official Website :: http://www.morningstarsecurity.com/research/geoipgen