Hello everybody. I'm newbie here and searched little bit but none answer found so I have general question for connection of client.
Is it required the client is accessible directly from the Internet or is possible to be connected in the network behind the NAT without direct access in direction Internet->client?
Connection client->Internet is OK for any service i.e. this is not filtered by any firewall along the path.
behind a NAT router is fine
your receiver initiate the connection to the server, so any response from the server will be routed to the client-receiver, no special firewall configuration required