Communication between two node-red applications

General
1

Hi folks,
I have node red applications running on two separate systems (PC). I wish to push /move data from one application to another.
I tried by hooking these computers on to a VPN (zerotier) and using MQTT broker (Mosquitto) but its not working..
Any alternatives ?
Please assist

2

Why?

In what sense?

If the two PCs are not on the same network, there are plenty of cloud based MQTT brokers.

3

I wanted to use Mosquitto broker to publish from one application and subscribe with the other and for that to work I needed to get them on a VPN (was not considering MQTT on cloud owing to involvement of cost).
I am using the mqtt nodes to publish but not receiving any data at the subscribed node.

4

Then you have a configuration issue. There is no fundamental reason this shouldn't work.

Have you tried the Mosquitto client tools to manually subscribe on the remote PC and submit on the local one? Does that work? If not, you likely have some kind of firewall issue on the PC's.

You could also, by the way, run Mosquitto on BOTH PC's and configure the brokers to sync topic trees.

1 Like
5

I have successfully used Node-red and an MQTT broker on a Raspberry Pi to exchange data with another Pi when both are connected over Zerotier.

6

MQTT Explorer is an excellent tool to help "see" what's happening with your MQTT broker(s).

7

Have you looked at the config file for Mosquitto - you are probably limiting the networks it can talk to - remember when using Zerotier it creates a new Virtual network between the nodes on the network. As such (dependant on version of Mosquitto) you may well have to enable communication on that network. Assuming you are running Linux and/or windows on each machine - you need to drop to a command prompt and first verify connectivity between the nodes by pinging each of them on their Virtual Addresses as assigned in the Zerotier Control panel.

Once you have done that then make sure that both of the Node Red instances are setup to talk to the broker - this broker config should be the Virtual network IP address not the real address of the machine it is running on

Craig

8

Thanks folks for the responses. I was in a bit of hurry so configured a public broker (Mqhive) to get started with.

I would still prefer an on-premises broker so will try out the suggestions provided...

9

Ok folks!.. Finally got it to work ! ... I had to register Zerotier as a private network and it started to send and receive data.

Thanks a ton for the assistance...