Proxy one server’s content through a different webserver. You may have an intranet (internal) server whose content you want exposed to the public internet without actually giving it a public IP. You can use the following rewrite rule on a public server to proxy requests to the private server.
Refer also to: Virtual Host Config or .htaccess?
Proxy Via HTTPS Protocol
Add the following rule to .htaccess or virtual host config:
RewriteRule "^(.*)$" "https://your-internal-servername/$1" [P] ProxyPassReverse "/" "https://your-internal-servername/"
This would cause all requests to the public server to be proxied to the ‘your-internal-servername’ server using the HTTPS protocol. To proxy via HTTP simply modify the action’s url attribute. This rule can also be modified to only proxy specific directories or file types.