Merge pull request #2076 from dokku/josegonzalez-patch-1

Add a note to dockerfile deploys concerning ports being exposed as http

docs/deployment/dockerfiles.md

@@ -19,6 +19,8 @@ Dokku will extract all tcp ports exposed using the `EXPOSE` directive (one port
 
 If you do not explicitly `EXPOSE` a port in your `Dockerfile`, dokku will configure the nginx proxy to listen on port 80 (and 443 for TLS) and forward traffic to your app listening on port 5000 inside the container. Just like buildpack apps, you can also use the `$PORT` environment variable in your app to maintain portability.
 
+When ports are exposed through the default nginx proxy, they are proxied externally as HTTP ports. At this time, in no case do we proxy plain TCP or UDP ports. If you'd like to investigate alternative proxy methods, please refer to our [proxy documentation](/dokku/proxy/).
+
 ## Customizing the run command
 
 By default no arguments are passed to `docker run` when deploying the container and the `CMD` or `ENTRYPOINT` defined in the `Dockerfile` are executed. You can take advantage of docker ability of overriding the `CMD` or passing parameters to your `ENTRYPOINT` setting `$DOKKU_DOCKERFILE_START_CMD`. Let's say for example you are deploying a base nodejs image, with the following `ENTRYPOINT`: