@mfalkvidd Is there a tutorial on how to accomplish this? When I go to the MQTT tutorial, it says to build an Ethernet setup first, followed by setting up either a DNS or static IPs, along with using ESP8266 libraries.

My Arduino modules will initially be Nano's. The only WiFi or Ethernet will be the ones built into the Rpi, used solely for accessing NodeRed. I'm wanting all communications in the system itself to be via the RS485 network if possible.

I'm not going to bore everyone with the details of my project, but here's the basics:

Raspberry pi, running Mosquito broker and node-red

Multiple Arduino "modules" for sensors & control

What I'm wondering about is if I can use RS-485s to create a network, all able to publish & subscribe to the topics on the MQTT broker running on the Rpi via the my sensors gateway library.