(New user for Mosquitto and MQTT in general, but old hand at IT)
I have set up a Mosquitto broker (1.5.5 via Homebrew) on my iMac (High Sierra 10.13.6) and I can publish and subscribe to messages.
I want to set up a bridge (to io.adafruit.com
for historical reasons) but I cannot get a connection between the two brokers.
Using Wireshark to view the communications between a 'straight forward' publish from the iMac to io.adafruit.com
I can see the connection packet and its contents. (The packet is acknowledged etc and the message published OK.) When I view the connection from the mosquitto broker to the adafruit broker, the only difference I can see is the "Version" field.
According to the MQTT protocol (V3.1.1) the version field should have a value of 0x04 (which the publish packet has) but the bridge connection request has a value of 0x84 (decimal 132, i.e. the top bit is set).
I suspect the version field is beig interpreted as 'invalid' by the remote broker and so the connect request is being ignored.
Is there some way I can control the "version" field value in the bridge setup?
I've tried altering the "bridge_protocol_version" in the mosquitto conf file but only the default (of 'mqttv311') seems to work - anything else seems to stop the local broker from starting.