MQTT Distributor WebSocket Connection Refused

Ignition Modules MQTT Modules
1

Hi all,

I’m trying to open a WebSocket listener in MQTT Distributor to expose some tag values to a webpage. I’m seeing some odd behaviour where the WebSocket port doesn’t appear to open at all, even after restarting the module.

Ignition version: 8.1.43
MQTT Distributor version: 4.0.24

Configuration:

  • WebSocket enabled on port 8090, non-TLS

  • Log shows: “Started WS WebSocket Server on hostname: 0.0.0.0, port: 8090”

Observed behaviour:

  • From the Ignition server itself, testing ws://localhost:8090/ via a simple HTML WebSocket client consistently returns ERR_CONNECTION_REFUSED

  • Tried changing the port and restarting the module, but the listener still won’t accept a connection locally

Any guidance would be appreciated.

2

There are no known recently known issues with this. However, that version of Distributor is pretty old. I would recommend upgrading regardless:

What client are you using to connect?

Also, do you have a firewall running that might be preventing connection?

3

Just testing using a plain new WebSocket(“ws://localhost:8090/”) inside a minimal HTML page - no MQTT library involved yet, just confirming whether the WebSocket listener will accept a basic connection.

I’ll upgrade to a more recent Distributor version and test again.
There’s also a possibility a firewall is interfering, so I’ll engage IT to confirm whether port 8090 is being filtered.

I’ll report back with the results once I’ve tried both.