IIS Reverse proxy and websockets, failed websocket handshake

Question

I am running a little website using IIS 7.5 on Windows Server 2008 R2. I've got a node.js application too running on port 3000.

Http calls from the website (client browser) are reverse proxied from http://example.com/node/whatever to http://localhost:3000/whatever. Everything works fine so far.

The problem is when i try to use socket.io.

I am receiving:

WebSocket connection to 'ws://example.com/socket.io/?EIO=3&transport=websocket&sid=adb9WRpoMFYRoS0vAAAB' failed: Error during WebSocket handshake: Unexpected response code: 502 

I am pretty sure, if i am not wrong, that:

It does forward the initial request to my server as the initial request to a websocket server is a standard HTTP request (with some additional headers). IIS does know about that and simply forwards the request. However, upon receiving the websocket request the websocket server sends a 101 response and switch into websocket mode. IIS does not understand the websocket traffic and it is not able to proxy that.

Is there a trick or solution to configure the reverse proxy for the ws:// adresses?

Solution

It seems that WebSocket support was not available in IIS 7.5.

http://www.iis.net/learn/get-started/whats-new-in-iis-8/iis-80-websocket-protocol-support

Comments

[Egidi]

that was just what I feared, isn't there any workaround on IIS 7.5?