title: Network port is occupied, but there is no processuse it
body: <p>My 4000 port is occupied, however, I want to kill the process which occupy it. When I use <code>netstat -anp | grep 4000</code> However the result is:</p>
  
  <pre><code>$ netstat -anp | grep 4000
  (Not all processes could be identified, non-owned process info
   will not be shown, you would have to be root to see it all.)
  tcp        0      0 0.0.0.0:4000            0.0.0.0:*               LISTEN      -
  </code></pre>
  
  <p>When I use <code>lsof -i:4000</code>, I got nothing, so the process which ever owned the port 4000 died, the port 4000 is still  not released?</p>
  
  <p>How to solve it?</p>