mqtt_sniffer

MQTT Sniffer

Subscribes to a broker and snoops on incoming data.

The MQTT Sniffer runs on Python 3. Although it was developed on and for small Linux systems, it will run on any Linux system. It should also be compatible with Mac or Windows systems.

Windows users will not be able to run the installation script. They will have to manually install the following Python 3 libraries:

• protobuf
• paho-mqtt

To install the program the easy way:

If on a Zum, copy mqtt_sniffer.tar.gz to the directory /home/devuser/apps .

If not on a Zum, copy it to wherever you want to run it from.

Unpack the tarball using this command: tar xzvf mqtt_sniffer.tar.gz

Change to the directory mqtt_sniffer .

Run the script install-mqtt_sniffer.sh and follow the on-screen prompts.

To install the program the harder way:

If on a Zum, change to the directory /home/devuser/apps .

If not on a Zum, change to the directory you want to run the program from.

Clone the repo:

git clone https://github.com/rdepew/mqtt_sniffer.git

Either:

• Run the script install-mqtt_sniffer.sh and follow the on-screen prompts.

Or:

• Install the dependencies by executing these three commands:

sudo apt update -y
sudo apt install -y python3-pip python3-protobuf
pip3 install paho-mqtt

To run the program:

Run it as

python3 mqtt_sniffer.py -i <broker-ip-address>

That only shows you the topic names. That may be all you need to see.

If you want to see all the data in a topic, then add the ‘-N’ option:

python3 mqtt_sniffer.py -i <broker-ip-address> -N <nodename>

The nodename is the first field after the DDATA keyword in a DDATA message.

There’s also a ‘-h’ or ‘--help' option if you need it.

Real-life examples:

python3 mqtt_sniffer.py -i 45.33.105.244
python3 mqtt_sniffer.py -i 45.33.105.244 -N Z9-PE2_3732

Other useful programs in the repo mqtt_sniffer:

• simple_listener.py - listens to everything that goes into the broker.
• listener_and_decoder.py - same as simple_listener.py, but it decodes any SparkPlug B DDATA payloads. If a "search string" is specified, filters output to report only MQTT topics which contain the search string. For example: python3 listener_and_decoder.py --search dogs reports only topics with dogs in the topic namespace.
• recv_image_via_mqtt.py - a snippet of code that saves a binary file sent using plain vanilla MQTT, not Sparkplug B.

What's this 'tahu' directory?

The 'tahu' directory has a small number of files copied from the Eclipse Tahu project (see https://github.com/eclipse/tahu). I don't need everything in the tahu repository, only the protobufs definitions and the Python files. Thanks to the great project team at Eclipse Tahu.

tahu and protobuf versions

This repository was updated to keep up with updates to Eclipse Tahu and Google Protobufs. This commit supports

• Eclipse Tahu version v1.0.0, from https://github.com/eclipse/tahu
• Google Protobufs v23.4, from https://github.com/protocolbuffers/protobuf/releases/tag/v23.4