mod_geoipをインストールする必要があり、mod_rewrite を使用して使用できます。
# stuff for initializing mod_geoip
GeoIPEnable On
GeoIPDBFile /path/to/GeoIP.dat
RewriteEngine on
# rules per country
# User IP from the UK, domain name appears as www.example.co.uk
RewriteCond %{ENV:GEOIP_COUNTRY_CODE} ^GB$
RewriteCond %{HTTP_HOST} !example.co.uk [NC]
RewriteRule ^/?(.*)$ http://www.example.co.uk/$1 [R,L]
# User IP from Australia, domain name appears as www.example.co.au
RewriteCond %{ENV:GEOIP_COUNTRY_CODE} ^AU$
RewriteCond %{HTTP_HOST} !example.co.au [NC]
RewriteRule ^/?(.*)$ http://www.example.co.au/$1 [R,L]
# All other IPs, domain name appears as www.example.com
RewriteCond %{ENV:GEOIP_COUNTRY_CODE} !^GB$
RewriteCond %{ENV:GEOIP_COUNTRY_CODE} !^AU$
RewriteCond %{HTTP_HOST} !example.com [NC]
RewriteRule ^/?(.*)$ http://www.example.com/$1 [R,L]