title: How to find an available port?
body: <p>I want to start a server which listen to a port. I can specify port explicitly and it works. But I would like to find a port in an automatic way. In this respect I have two questions.</p>
  
  <ol>
  <li><p>In which range of port numbers should I search for? (I used ports 12345, 12346, and 12347 and it was fine).</p></li>
  <li><p>How can I find out if a given port is not occupied by another software?</p></li>
  </ol>