Good day.
The port for websocket is already specified in the flashphoner.properties configuration file:
Possible settings for the WS connection, you can see in the file
flashphoner.properties.
But note that you can publish WebRTC stream via Secure Websocket only (wss).
Please write in which case you needed a WS connection (not secure).
Perhaps you are having problems with creating a certificate, please read the
documentation.