title: Why a STUN Server Needs Two Different Public IP addresses
body: <p>I have took a look to STUN Server settings in <a href="http://www.igniterealtime.org/projects/openfire/index.jsp">openfire</a>, and this statement from there: </p>
  
  <p>"In order to act as a STUN server, two different public IP addresses on the same machine are required, as well as two different port numbers for each IP."</p>
  
  <p>I have researched on google, and generally stun servers need two public IPs, what is reason for that? </p>