title: Keep alive does not respond with ACK if interval more than 5 minutes
body: <p>I am using the <strong>SetKeepAlive</strong> method with 10 minutes interval and I get the following traces without ACK:</p>
  
  <ul>
  <li>TCP:[Keep alive]Flags=...A...., SrcPort=20100, DstPort=13529, PayloadLen=1, </li>
  <li>TCP:[Keep alive]Flags=...A...., SrcPort=20100, DstPort=13529, PayloadLen=1, </li>
  <li>TCP:[Keep alive]Flags=...A...., SrcPort=20100, DstPort=13529, PayloadLen=1, </li>
  </ul>
  
  <p>But if I change to 5 minutes, I get the ACKs</p>
  
  <ul>
  <li>TCP:[Keep alive]Flags=...A...., SrcPort=20100, DstPort=15067, PayloadLen=1, </li>
  <li>TCP:[<strong>Keep alive ack</strong>]Flags=...A...., SrcPort=15067, DstPort=20100, PayloadLen=0, </li>
  </ul>
  
  <p>I am using a TcpClient socket with ReceiveTimeout = 0 and a SslStream with ReadTimeout = Timeout.Infinite</p>
  
  <h2>Q1) Any suggestion on how to set the keep alives for more than 5 minutes and get ACK from the other side?</h2>
  
  <h2>Q2) Is it require to set Keep-Alives both ends? If yes do the interval need to match?</h2>