title: Java socket between 2 hosts on different subnets
body: <p>In Java, we can open a ServerSocket with <em>new ServerSocket(port)</em>, and connect to it with new *Socket(server_adress",port)*; <br/>
  But how to connect, if server is in a different network, while both networks are behind a NAT.</p>
  
  <p>I know that there must be a solution. Skype and other applications already found it.</p>
  
  <p>Any ideas ?</p>
  
  <p>Regards, Andrew.</p>