So in my installation where Port 3000 is blocked by wanderer, my /var/www/cryptpad/config/config.js looks like this:
/* httpPort specifies on which port the nodejs server should listen.
* By default it will serve content over port 3000, which is suitable
* for both local development and for use with the provided nginx example,
* which will proxy websocket traffic to your node server.
*
*/
httpPort: 3001,
/* httpSafePort allows you to specify an alternative port from which
* the node process should serve sandboxed assets. The default value is
* that of your httpPort + 1. You probably don't need to change this.
*
*/
// httpSafePort: 3001,
/* Websockets need to be exposed on a separate port from the rest of
* the platform's HTTP traffic. Port 3003 is used by default.
* You can change this to a different port if it is in use by a
* different service, but under most circumstances you can leave this
* commented and it will work.
*
* In production environments, your reverse proxy (usually NGINX)
* will need to forward websocket traffic (/cryptpad_websocket)
* to this port.
*
*/
websocketPort: 3003,