=====MQTT=====

MQTT Broker:

  mosquitto
  
Install:

  apt install mosquitto mosquitto-clients
or
  snap install mosquitto mosquitto-clients
  
Commands:

   mosquitto_pub -h 10.0.0.10 -t SENSOR3/+ -m '123' -d
   mosquitto -v -c /etc/mosquitto/mosquitto.conf

Trigger relay:

  mosquitto_pub -t <devicename>/GPIO/2 -m 0                      #on
  mosquitto_pub -t <devicename>/GPIO/2 -m 1                      #off

Gosund (switch power1):

  mosquitto_pub -t <devicename>/cmnd/Power1 -m OFF
  mosquitto_pub -t <devicename>/cmnd/Power1 -m ON

To send a message to a mqtt server:

https://diy.waziup.io/sensors/publish_using_MQTT/publish_using_MQTT.html

https://github.com/plapointe6/EspMQTTClient                                      #authentication example!

====Interfaces====

Mosquitto listens on default on localhost (127.0.0.1). If you want to make mosquitto listen on all interfaces, you have to edit

  /etc/mosquitto/mosquitto.conf
and add
  
  #individual
  listener 1883 0.0.0.0
  allow_anonymous true
  
Afterwards you have to restart mosquitto to make it active:

  systemctl restart mosquitto.service
  
Check:

  netstat -an | grep 1883
  tcp        0      0 0.0.0.0:1883            0.0.0.0:*               LISTEN