title: How to use Traefik for WebSocket backend
body: <p>I am trying to configure Traefik for a WebSocket app, I just try with a simple WS app on docker: <a href="https://hub.docker.com/r/jmalloc/echo-server/" rel="nofollow noreferrer">https://hub.docker.com/r/jmalloc/echo-server/</a></p>
  
  <p>To test it I use Chrome SimpleWebSocketClient, so if I use the IP:Port of the app it works fine. If I add the Traefik DNS it fails, I just try with other WS server and clients and fails too, so it would be something of Traefik.</p>
  
  <p>I just try with Traefik versions:</p>
  
  <pre><code>-v1.3.0/raclette
  -v1.2.3/morbier
  </code></pre>
  
  <p>Those are my Traefik rules:</p>
  
  <pre><code>[backends.ws-test-backend]
      [backends.ws-test-backend.LoadBalancer]
        method = "drr"
      [backends.ws-test-backend.servers.server1]
      url = "ws://172.16.8.231:3000"
  
  [frontends.ws-test-frontend]
    backend = "ws-test-backend"
    passHostHeader = true
    entrypoints = ["http","https","ws", "wss"]
      [frontends.ws-test-frontend.routes.manager]
      rule = "Host:ws-test.ikcloud.ikerlan.es"
  </code></pre>
  
  <p>What could it be wrong?
  Any recommended reverse proxy for doing this?</p>