broker

# MQTT broker example

## Overview

This example runs a TCP broker on a specified host and port.

### How to use this example

Choose the preferred connection in the project configuration menu, build and run the example.
After it connects via the specified network interface, it starts the mosquitto broker, which by default listens on all IPv4 interfaces ("0.0.0.0").

If you enabled also the mqtt client, this example will connect to the local broker, subscribe and publish to a topic.

You can connect to the ESP32 mosquitto broker using some other client using the ESP32 IPv4 address and the port specified in the project configuration menu.

### Test version

This example is also used for testing on loopback interface only, disabling any actual connection, just using the local mqtt client to the loopback interface.

### Example output

```console
I (477) main_task: Calling app_main()
0: mosquitto version 0.1.0 starting
0: Using default config.
0: Opening ipv4 listen socket on port 1883.
0: mosquitto version 0.1.0 running
I (1507) test: Other event id:7
1: New connection from 127.0.0.1:56424 on port 1883.
1: New client connected from 127.0.0.1:56424 as ESP32_d58788 (p2, c1, k120).
I (1528) mqtt_broker: MQTT_EVENT_CONNECTED
I (1528) mqtt_broker: sent subscribe successful, msg_id=54859
I (1538) mqtt_broker: MQTT_EVENT_SUBSCRIBED, msg_id=54859
I (1538) mqtt_broker: sent publish successful, msg_id=0
I (1548) mqtt_broker: MQTT_EVENT_DATA
I (1548) mqtt_broker: TOPIC=/topic/qos0
I (1548) mqtt_broker: DATA=data
```