title: tcp application exit will send FIN always?
body: <p>When a TCP application exits it will  send a FIN packet.</p>
  
  <p>Consider a tcp client which get connected to a always listening server(server never exits).</p>
  
  <p>if the tcp client is exiting abruptly after few exchange of packets, will it always send a FIN packet to the server?</p>
  
  <p>Thx!</p>