mosquitto-clients

name	mosquitto-clients
description	Auth/lab ref: Mosquitto client tools, primarily `mosquitto_pub` and `mosquitto_sub`, for interacting with MQTT brokers.
compatibility	Linux, Windows, macOS; mosquitto client package installed.
metadata	{"author":"AeonDave","version":"1.0"}

Mosquitto Clients

Small, sharp MQTT tooling for quick broker interaction without writing a custom client first.

When to use mosquitto-clients

Use these tools when you need to:

• subscribe to MQTT topics and observe message flow
• publish controlled messages to a topic
• validate broker auth, TLS, or topic structure quickly

Quick Start

# Subscribe to everything verbosely
mosquitto_sub -h broker.local -t '#' -v

# Publish a test message
mosquitto_pub -h broker.local -t test/topic -m 'hello'

High-Value Workflows

Authenticated subscribe/publish

mosquitto_sub -h broker.local -p 1883 -u user -P pass -t 'sensors/#' -v
mosquitto_pub -h broker.local -p 1883 -u user -P pass -t 'actuators/cmd' -m 'on'

TLS example

mosquitto_sub -h broker.local -p 8883 --cafile ca.pem -t '#' -v

Practical Notes

• Start with a broad read-only subscription pattern like # only in controlled environments.
• Use -v so topic names and payloads stay paired in output.
• Pair with packet capture or device docs when topic semantics are unclear.

Caveats

• Publishing to a live broker can trigger real actions.
• Some brokers enforce ACLs, retained messages, or TLS requirements that change what you see.
• Topic wildcards are powerful and noisy; use them intentionally.

Resources

No bundled scripts/, references/, or assets/. Use the Mosquitto man pages for TLS, session, retained-message, and last-will options.