Explanation needed for FW rule


I’m running a Synology NAS with a Plex Media Server in green network. I have set up a port forwarding to reach this server from the internet and from the Sonos controller to stream any music from this media server to the Sonos speaker. (Sonos uses a cloud service and cannot access Plex locally but using a redirection over the internet).

Source: Standard networks: RED
Use NAT, DNAT, Firewall Interface Automatic
Destination: Host:
Protocol: Preset

Using this rule I can access Plex server from internet and play any music available. However, when trying to access this server from the Sonos app, playing the same music fails.

I already know you to get around this issue, by modifying the above FW rule and set:

Source: Standard networks: ANY

So can sbdy please explain the difference between Source: RED and ANY in this case?


I don’t know why that’s the case but why don’t you just have a look into the firewall log to see the recognized input source when the packages are beeing dropped?