title: TCP four-way handshake
body: <p>Four-way handshake connection termination can be reduced to three-way and even two way one. Is it possible the three-way handshake connection establishment would be extended to four-way?</p>
  
  <pre><code>SYN=&gt;
  &lt;=ACK
  &lt;=SYN
  ACK=&gt;
  </code></pre>