title: Adding second instance of Firefox with Marionette (change port)
body: <p>I'm having great difficulties creating two instances of firefox via marionette. Having one instance works fine: </p>
  
  <p>Starting up Firefox with marionette enabled:</p>
  
  <pre><code>firefox.exe -marionette
  </code></pre>
  
  <p>Controlling it with python:</p>
  
  <pre><code>from marionette import Marionette
  client = Marionette('localhost', port=2828)
  client.start_session()
  client.execute_script("alert('o hai there!');")
  </code></pre>
  
  <p>Now I'd like to add a second client alongside the current one, a <a href="https://groups.google.com/forum/#!msg/mozilla.tools.marionette/2JdqdzpUWqY/gtq86DqeEQAJ" rel="nofollow">quick search</a> resulted in the --address command:   </p>
  
  <pre><code>firefox.exe -marionette --address=localhost:2829
  </code></pre>
  
  <p>Trying to control it via python:</p>
  
  <pre><code>from marionette import Marionette
  client = Marionette('localhost', port=2829)
  client.start_session()
  client.execute_script("alert('o hai there!');")
  </code></pre>
  
  <p>I can't seem to get this to work, however:</p>
  
  <pre><code>error: [Errno 10061] No connection could be made because the target machine actively refused it
  </code></pre>
  
  <p>Any help is greatly appreciated.</p>