title: What is the difference between DEALER and ROUTER socket archetype in ZeroMQ?
body: <p>What is the difference between the <strong><code>ROUTER</code></strong> and the <strong><code>DEALER</code></strong> socket archetypes in zmq?</p>
  
  <p>And which should I use, if I have a server, which is receiving messages and a client, which is sending messages? The server will never send a message to a client.</p>
  
  <p><strong>EDIT:</strong> I forgot to say that there can be several instances of the client.</p>