I'm using Eclipse's Paho MQTT library to stream DAQ data to a PC.
It all works fine using the cloud based Eclipse test broker over WiFi. Unfortunately my application will be in a place where there is no WiFi available. So I'm trying to do this through a LAN via the ethernet port using Mosquitto as a local broker. To be clear the application will have no internet access via either WiFi or LAN. The network needs to be just Pi to PC.
Raspberry Pi: Client: DAQ >> local broker >> eth0 >> PC: Client
I can ping my Pi from the PC successfully and the DAQ code connects with the local broker with no error & broadcasts its data.
But on the PC: Client side I get the following error,
ConnectionRefusedError: [WinError 10061] No connection could be made because the target machine actively refused it
Is there some security lock out going on here?
127.0.0.1), hence nothing is listening on the same port via the inet interface (wlan or eth), so the OS refuses the connection via the TCP mechanism as per my answer. You could combine this with the bit edited out of the question.