master and slave controllers on different networks

[paul]

Hi Dan,

Is it possible to connect the master and slave controllers on different networks (i.e., with distinct public ip addresses)?

Here is what I have tried:

0. I installed mosquitto broker on my master controller.

1. I installed openvpn on the master controller so that I can access it from outside my home network via:
http://master01.ddns:xxxx, where xxxx denotes port forwarding which I configure on my router.

2. On the master controller, for mqtt_bases setting:
broker host: localhost
broker port: 1883
...

Then to verify that the master can control the slave when they are on the same network:

3. On the slave controller, for mqtt_base setting:
broker host: 192.168.0.167 # which is the local ip address of the master controller
broker port: 1883
...

I have verified the above setup works as expected.

4. Now I put the slave controller on a different network, and try to connect to the master via the master's public ip address:
broker host: master01.ddns:xxxx
broker port: 1883


Actually I have tried various things for #4 but none works so far:
4a. broker host: master01.ddns:xxxx
4b. broker host: master01.ddns:1883 # of course I set my router to port forward 1883 as well
4c. broker host: master01.ddns
4d. broker host: http://master01.ddns:xxxx
4e. broker host: http://master01.ddns:1883
4f. broker host: http://master01.ddns

So I am wondering if I am attempting to do something that is not possible.

If not possible, what about using an online mqtt broker instead of a private one?

I haven't looked at the plugin codes yet, but do you know offhand if I need to modify anything?

I am hoping if I use the same topic for both publication and subscription, as the plugins do in mqtt_base for master and slave respectively, then maybe the plugins will work without modifications.

--Paul