title: JSch session timeout limit
body: <p>I'm using JSch 0.1.50 to set up a connection to the remote server for my CI Jenkins plugin. Let's assume I'm trying to use here <code>session.connect(60000);</code> for the timeout 60 sec:</p>
  
  <pre><code>Session session = null;
  try {
      JSch jsch = new JSch();
      if (rsaIdentity != null &amp;&amp; !rsaIdentity.equals("")) {
          jsch.addIdentity(rsaIdentity.trim());
      }
      session = jsch.getSession(serverLogin, serverHost, Integer.parseInt(serverPort));
      session.setPassword(getDescriptor().getOpenPassword(encryptedPasswordString));
      session.setConfig("StrictHostKeyChecking", "no"); // not use RSA key
  
      int timeOut = Integer.parseInt(getDescriptor().getConnectionTimeOut());
  
      session.connect(60000);
  
  } catch (SocketTimeoutException e) {
      logger.error(e.getMessage());
      return false;
  } catch (JSchException e) {
      logger.error(e.getMessage());
      return false;
  }
  </code></pre>
  
  <p>But in fact during the execution of this code during the connection to pretty slow sever I'm facing the timeout <code>Exception</code> in approximately 20 seconds every time:</p>
  
  <pre class="lang-none prettyprint-override"><code>2016-01-25 13:15:55.982 [INFO] Connecting to server: devsrv26:22 as [user] ...
  2016-01-25 13:16:16.991 [ERROR] java.net.ConnectException: Connection timed out: connect
  2016-01-25 13:16:16.992 com.jcraft.jsch.JSchException: java.net.ConnectException: Connection timed out: connect
  2016-01-25 13:16:16.992     at com.jcraft.jsch.Util.createSocket(Util.java:389)
  2016-01-25 13:16:16.993     at com.jcraft.jsch.Session.connect(Session.java:215)
  2016-01-25 13:16:16.993     at com.mycomp.jenkins.MyPlugin.perform(MyPlugin.java:225)
  </code></pre>
  
  <p>76991-55982=21008 msec</p>
  
  <p>Does anyone know what is the reason for this 20 seconds timeout?</p>