Re: CloudFoundry websocket failed: Establishing a tunnel via proxy server failed

Nicholas Calugar

Hi Behroz,

There are a couple items to consider when doing web sockets on Cloud

1. Port 4443 is recommended for load balancers that don’t support passing
the WebSocket handshake requests to the CF router on the same port as
HTTPS. [1] Read more about this here. You’ll have to confirm this setup
with your operator, the person that manages your Cloud Foundry deployment.
2. If your app server does not support upgrading to WebSocket, you’ll have
to open an additional port using the Cloud Foundry API, you can use any
port in the range 1024-65535. [2] The application update endpoint takes a
list of ports, remember you’ll still want 8080 open for your REST API.
Please note, this is an experimental feature and it is not related to the
port mentioned above on the load balancer.
3. If you are using an additional port for WebSockets, you’ll need an
additional route and route mapping to use that port. [3] See the mapping an
app and a route documentation.

Hope this helps, I’ve actually never tried it but it is supported.



Nicholas Calugar
Product Manager - Cloud Foundry API
Pivotal Software, Inc.

On November 19, 2016 at 4:21:22 AM, Behroz Sikander (bsikander(a)

Note: I am not using Pivotal CF.

I have a java application deployed on CloudFoundry. I am using embedded
Jetty to host my Jersey REST API. This API is by default exposed on port
8080 by cloud foundry.

My application also needs some websockets to stream data to the browser. I
am using Java-WebSocket ( for
this. On my local machine, I was using port 8887 for my websocket
connection. Everything worked fine.

After deploying on CloudFoundry, I can access my REST API but not my
websocket. After searching a bit online, I found that websocket connections
are only allowed on port 4443 (

I changed my server side to reflect this

import org.java_websocket.server.WebSocketServer;
public class MyWebSocket extends WebSocketServer {
public MyWebSocket() throws UnknownHostException {
super(new InetSocketAddress(4443));

public void onOpen(org.java_websocket.WebSocket websocket, ClientHandshake
handshake) {
// Handle this

On my client side, I am connecting the websocket using the following


But I am getting the following exception.

"WebSocket connection to 'wss://' failed: Establishing a
tunnel via proxy server failed"

I also tried to connect the websocket on server side using "PORT"
environment variable of CF but I get "Address already in use" error in
Java-WebSocket because 8080 is already taken by Jersey REST API.

I have tried many different things but I am unable to figure this out. Any
help would be awesome.

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