http://www.ols.es/exim/dlext/

ip2country

   Get country from reverse dns country tld or from MaxMind GeoIP
   http://www.maxmind.com/app/geoip_country if not
   possible (minimizes GeoIP outdated database records). Requires GeoIP C
   API http://www.maxmind.com/app/c

   Usage:
   ${dlfunc{/usr/local/exim/exim-ext.so}{ip2country}{$sender_host_address}}
   returns: 2 letter iso code for given ip address or "--" if not found.