JeoIP is a Java implementation of net/GeoIP, which looks up an IPV4
address in a local file and returns the country that it is in.
The database is maintained, and the GeoIP code provided, by MaxMind,
who sells on subscription more detailed datatabases that identify the
sender down to particular regions within a country. 
See http://www.maxmind.com/

JeoIP does not use any code from GeoIP but does use its data file.
JeoIP was written to make the database accessible from within
Java Servlet/JSP web sites without having either to run an
external program or to link with "native code".
There are functions that return the country name as well as
its two- and three-letter ISO-3166 country code.
