[AndyL]

If I understand correctly, the master is the "local" device. If so, then I'm rather surprised you needed to forward the port that was using to connect out to the remote devices. There shouldn't be any port forwarding going on when it makes a connection out. Maybe it is just that "unusual" ports are being blocked in general and adding the forwarding config unblocked it.

Anyway, good that you got it sorted. And I might have to investigate some of those "jamming" services. I'm missing playing with others.

Andy