So is this how your setup?
That is not streaming - that is an index with graphics that points you to where to open the file at. That is NOT a streamer!! Seems very sim to YAMJ.
Also -- pfsense is not involved in this sort of configuration anyway. Unless your talking clients on one network segment and server/nas on different network segment.
Pfsense does not come into play for devices on the same network talking to each other.
as to stop stealing?? Like I said you DONT!! If they have READ, they have COPY - PERIOD!