title: Building a webserver, client doesn't acknowledge HTTP 200 OK frame
body: <p>I'm building my own webserver based on a tutorial.
  I have found a simple way to initiate a TCP connection and send one segment of http data (the webserver will run on a microcontroller, so it will be very small)</p>
  
  <p>Anyway, the following is the sequence I need to go through:</p>
  
  <ol>
  <li><p>receive SYN </p></li>
  <li><p>send SYN,ACK</p></li>
  <li><p>receive ACK (the connection is now established)</p></li>
  <li><p>receive ACK with HTTP GET command</p></li>
  <li><p>send ACK</p></li>
  <li><p>send FIN,ACK with HTTP data (e.g 200 OK)</p></li>
  <li><p>receive FIN,ACK &lt;- I don't recieve this packet!</p></li>
  <li><p>send ACK</p></li>
  </ol>
  
  <p>Everything works fine until I send my acknowledgement and HTTP 200 OK message.
  The client won't send an acknowledgement to those two packages and thus
  no webpage is being displayed.
  I've added a pcap file of the sequence how I recorded it with wireshark.</p>
  
  <p>Pcap file: <a href="http://cl.ly/5f5/httpdump2.pcap" rel="nofollow noreferrer">http://cl.ly/5f5/httpdump2.pcap</a></p>
  
  <p>All sequence and acknowledgement numbers are correct, checksum are ok. Flags are also right.
  I have no idea what is going wrong.</p>