using reverse proxy,

google key: linux http https reverse proxy load balancer/

Deploy DNSSEC at Authoritative DNS Servers

Using a load balancer or reverse proxy http://drupal.org/node/425990

Pound – Light weight Reverse Proxy and Load Balancer

Using Pound as a reverse Proxy

K/n , d/n: http://en.wikipedia.org/wiki/Proxy_server

Apache Module mod_proxy