title: Selenium Grid can't manage nodes in the private network
body: <ol>
  <li><p>Server side</p>
  
  <p>Our Selenium Grid server has public IP-address (104.131.xxx.xxx)</p>
  
  <pre><code>java -jar selenium-server-standalone-3.4.0.jar -role hub
  </code></pre></li>
  <li><p>Nodes</p>
  
  <p>There are node computers in the private network (192.168.43.xxx). They are able to connect to the Selenium Server without any problems:</p>
  
  <pre><code>java -jar selenium-server-standalone-3.4.0.jar -role webdriver -hub http://104.131.xxx.xxx:4444/grid/register -port 3456
  </code></pre></li>
  </ol>
  
  <p><a href="https://i.stack.imgur.com/RC2n8.png" rel="nofollow noreferrer">Selenium Grid Console</a></p>
  
  <ol start="3">
  <li><p>The issues</p>
  
  <p>3.1 There are repeated messages on the server:</p>
  
  <pre><code>Registered a node http://192.168.43.248:3456
  Marking the node http://192.168.43.248:3456 as down: cannot reach the node for 2 tries
  Unregistering the node http://192.168.43.248:3456 because it's been down for 60060 milliseconds
  Cleaning up stale test sessions on the unregistered node http://192.168.43.248:3456
  
  Registered a node http://192.168.43.248:3456
  Marking the node http://192.168.43.248:3456 as down: cannot reach the node for 2 tries
  ......
  </code></pre>
  
  <p>3.2 We can't start any test. When we try to start we got:</p>
  
  <pre><code>Got a request to create a new session: Capabilities [{marionette=true, loadImages=false, acceptInsecureCerts=true, browserName=firefox}]
  Trying to create a new session on test slot {seleniumProtocol=WebDriver, browserName=firefox, maxInstances=5, platform=WIN10}
  Marking the node http://192.168.43.248:3456 as down: cannot reach the node for 2 tries
  Unregistering the node http://192.168.43.248:3456 because it's been down for 60050 milliseconds
  Cleaning up stale test sessions on the unregistered node http://192.168.43.248:3456
  Removed a session that had not yet assigned an external key f83395be-cb27-43a3-8999-b5573f387715, indicates failure in session creation PROXY_REREGISTRATION
  Registered a node http://192.168.43.248:3456
  Marking the node http://192.168.43.248:3456 as down: cannot reach the node for 2 tries
  </code></pre>
  
  <p>3.3 The test's trace:</p>
  
  <pre><code>selenium.common.exceptions.WebDriverException: Message: Error forwarding the new session Error forwarding the request Connect to 192.168.43.248:3456 [/192.168.43.248] failed: Connection timed out (Connection timed out)
  </code></pre></li>
  </ol>
  
  <hr>
  
  <p><strong>Should we create VPN-network or Selenium Grid has some special way to manage this issues?</strong></p>
  
  <p>P.S. When we move the Selenium Server to the local environment everything works.</p>