title: NodeJS Server to NodeJS Client notification
body: <p>I've the following situation.</p>
  
  <p>I have a <strong>hosted node server</strong> application in Amazon, and I have <strong>node clients</strong> in our users, which serves in their internally network, so this is a server/client node app.</p>
  
  <p>The situation is, my hosted node, must send notifications to our node clients, and this node clients does not necessary have a valid internet IP and I can't access them directly. </p>
  
  <p>My hosted node have to notify its clients just a few times a day in random times, and this will not occurs all days, <strong>BUT</strong> when some condition is achieved in that server, the clients must be notified.</p>
  
  <p>So my options until now are: </p>
  
  <ul>
  <li>My node clients send a request from time to time to check that specific condition, which is a dummy way to do that;</li>
  <li>I can use websockets, and it works, but websockets keep the connection open to all my clients.</li>
  </ul>
  
  <p>This two options does not appears to fit my requirements.</p>
  
  <p>There is some functionality that works like push notifications, where my node server sends a notification to my node client? Thanks in advance. </p>