---
tags:
  - Linux
  - Debian
  - mqtt
---

## Config

At `/etc/mosquitto/mosquitto.conf`.

Most important lines:

```
listener 1883
allow_anonymous true
```

This means `mosquitto` will run on port:1883 and that I am not using
authentication with requests to the broker.

### Websockets

In order to enable [websockets](./Web_sockets.md), must create a config file at
`/etc/mosquitto/mosquitto.conf/websockets.conf`:

```
# /etc/mosquitto/mosquitto.conf/websockets.conf`
listener 8083
protocol websockets
```

This is only relevant if you require access from outside of the local network.

## Basic usage

## Create a topic

```sh
mosquitto_sub -d -t test_topic
```

This then enters listening mode and takes control of terminal:

```
$ mosquitto_sub -d -t test_topic
Client (null) sending CONNECT
Client (null) received CONNACK (0)
Client (null) sending SUBSCRIBE (Mid: 1, Topic: test_topic, QoS: 0, Options: 0x00)
Client (null) received SUBACK
Subscribed (mid: 1): 0
```

## Publish to a topic

From my other machine I install `mosquitto` and:

```sh
mosquitto_pub --host 192.168.68.53 --port 1883 --topic test_topic --message 'hello world'
```

This registers on the broker device:

```
Client (null) received PUBLISH (d0, q0, r0, m0, 'test_topic', ... (11 bytes))
hello world
```