title: TCP Three way handshake - Piggybacking ACKs
body: <p>I understand that in the three-way handshake, sometimes the receiving end will send a SYNACK packet when establishing a connection (piggybacking), but when would it ever send a SYN and then an ACK packet?</p>
  <p>For example:</p>
  <blockquote>
  <p>-&gt;SYN</p>
  <p>&lt;-SYN_ACK</p>
  <p>-&gt;ACK</p>
  </blockquote>
  <p>versus:</p>
  <blockquote>
  <p>-&gt;SYN</p>
  <p>&lt;-SYN</p>
  <p>-&gt;SYN_ACK</p>
  </blockquote>
  <p>Thanks!</p>