title: Netscaler: sudden ACK,RST packet
body: <p>One of our clients uses Netscaler as a balancer middleware between Fuse server and our Tomcat-hosted software.
  Currently we are experiencing strange communication behavior between our software and netscaler (we're making SOAP-request using Spring-WS): after some time, since a request to netscaler is being made and response is being awaited, netscaler sends ACK,RST packet to our server, and, consequently, Java throws "connection reset" IOException.
  The tcp dump is as follows:
  <a href="https://i.stack.imgur.com/HCkf4.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/HCkf4.png" alt="fireshark screenshot"></a></p>
  
  <p>As per netscaler docs, <code>Win</code> field of reset packet contains error code which is <code>9300</code> in this situation and means 'cleanup of idle connections', which in it's turn means that netscaler runs "zombie" process, which cleans up idle connections and that this process has recognized our connection as being idle.</p>
  
  <p>Why would connection be treated as being <code>idle</code> by netscaler in this case?</p>
  
  <p><strong>UPDATE</strong>
  Here is more complete communication log:
  <a href="https://i.stack.imgur.com/kEo0f.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/kEo0f.png" alt="enter image description here"></a></p>