title: How to proxy WebSockets in Traefik?
body: <p>I'm trying to set up Upsource to work behind Traefik: <a href="https://www.jetbrains.com/help/upsource/proxy-configuration.html" rel="noreferrer">https://www.jetbrains.com/help/upsource/proxy-configuration.html</a></p>
  
  <p>traefik is listening to port 8008 and 8443 (since 80/443 will be used for another):</p>
  
  <pre><code>--entryPoints='Name:http Address::8008 Redirect.EntryPoint:https' --entryPoints='Name:https Address::8443 TLS'
  </code></pre>
  
  <p>docker labels:</p>
  
  <pre><code>labels:
    traefik.backend: upsource
    traefik.enable: "true"
    traefik.port: "8080"
    traefik.frontend.rule: "Host:review.domain.com"
  </code></pre>
  
  <p>In <code>conf/internal/bundle.properties</code>, <code>base-url</code> is configured as follow:</p>
  
  <pre><code>base-url=https\://review.domain.com\:8443/
  </code></pre>
  
  <p>problem:</p>
  
  <pre><code>time="2017-09-20T03:23:59Z" level=error msg="Error getting ACME certificates [review.domain.com] : Cannot obtain certificates map[review.domain.com:acme: Error 400 - urn:acme:error:connection - Connection refused
  Error Detail:
          Validation for review.domain.com:443
  </code></pre>
  
  <p>Why it validate for port 443 instead of 8443?</p>
  
  <p>Moreover, to proxy WebSockets in Nginx:</p>
  
  <pre><code>        proxy_set_header Upgrade $http_upgrade;
          proxy_set_header Connection "upgrade";
          proxy_pass http://upsourcemachine.domain.local:1111;
          proxy_pass_header Sec-Websocket-Extensions;
  </code></pre>
  
  <p>Can you confirm that Traefik support WebSockets? And if so, how to configure?</p>