Mosquitto bridge connect uses version 132

[vk3...@gmail.com]

(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.

Susan

[vk3...@gmail.com]

(Can't seem to edit my posting)

To be clear, the 'Version' field I refer to is the label given by Wireshark to the packet field.

In the MQTT protocol, it is referred to as the 'Protocol Level' byte (3.1.2.2 in the protocol document)

Susan

[Karl Palsson]

Set try_private = false. You'll often need that when connecting
to non-mosquitto brokers, though it's commonly implemented to
help with bridge detection.

[vk3...@gmail.com]

Magic - thank you.

I must admit that I would not have connected the name with the effect.

Susan