title: How IP divides to point sub domains
body: <p>I believe that default domain some <code>www.domain.com</code> points to some IP address <code>123.123.123.123</code> here when a sub domain is created which points to the same IP address. How the division of IP address works in real time to distribute IP to various sub domains. Do it uses port numbers to each sub domain? or any other method?</p>