Network/Reverse proxy

Install a reverse proxy behind firewall, use HAProxy.

Really great answer (especially links below) here: http://stackoverflow.com/a/366212 to this question here: https://stackoverflow.com/questions/224664/difference-between-proxy-server-and-reverse-proxy-server

Copied links for convenience:

Content Delivery Network

forward proxy software (server side)

reverse proxy software for HTTP (server side)

reverse proxy software for TCP (server side)

see also: