Hello.
UDP ports are used to transfer audio and video data. In simplest case, the following range that is set in WCS_HOME/conf/flashphoner.properties file out of the box, is enough for WebRTC streaming:
Code:
media_port_from =31001
media_port_to =32000
This doc describes in details what ports are used for what purposes. At this page you can find settings to change default ports range (search by "port_from" and "port_to" keywords).