title: Http requests from external and internal IP
body: <p>I have web server with Internet domain name. That server has 2 IP: <code>Internal</code> and <code>External</code>.
  My web application receives <code>HTTP</code> requests from Internet (external IP). If that web app makes <code>HTTP</code> request to other web server inside our Intranet network, but which also has 2 IP (external and internal), which IP will be used by first server?
  And if I receive request from Internet at external IP how can I change IP to internal for doing <code>HTTP</code> requests to other server inside Intranet?</p>