title: traefik hostname works for web apps but not for mongodb
body: <p>I'm running a mongo instance with docker-compose and traefik.</p>
  
  <pre><code>myapp-mongo:
    build: ../images/myapp-mongo
    restart: always
    ports:
      - "27017:27017"
    labels:
      - "traefik.ports=27017,27018"
      - "traefik.backend=myapp-mongo"
      - "traefik.frontend.rule=Host:myapp-mongo.docker.localhost"
    networks:
      - development
    environment:
      - MONGO_USER=${MONGO_USER}
      - MONGO_PASSWD=${MONGO_PASSWD}
      - MONGO_AUTHDB=${MONGO_AUTHDB}
  </code></pre>
  
  <p>Mongo is running fine and I can connect using <code>127.0.0.1</code> from my Mac.</p>
  
  <p>The problem is that I can't connect using hostname <code>myapp-mongo.docker.localhost</code>. It only works using IP 127.0.0.1.</p>
  
  <p>Trying to ping the IP 127.0.0.1 responds ok, but trying to ping the hostname doesn't work.</p>
  
  <p>I've already added <code>127.0.0.1 proxy.docker.localhost</code> into <code>/etc/hosts</code> to get traefik working.</p>
  
  <p>All other web apps has hostnames working fine like eg <code>myapp.docker.localhost</code>. This problem is only happening with this mongodb container.</p>