Introduction

The introduction of the container feature into the RouterOS made it possible to run all kinds of servers for all sorts of tasks inside the router. This is especially relevant for people, who want to reduce the number of devices in their network. Instead of running a server on a separate device/machine, why not run it inside the router?

In this guide, we will showcase how to install a basic MQTT broker (or in other words, server) called eclipse-mosquitto. MQTT protocol is a very popular choice, especially in IoT topologies. It is an open OASIS and ISO standard lightweight, publish-subscribe network protocol that transports messages between devices. A typical topology consists of an MQTT publisher (a device that sends information), an MQTT broker (a server where the data is stored), and an MQTT subscriber (a device that listens to the data published on the server).

RouterOS supports MQTT publish, subscribe feature, and, now, we can also run the MQTT broker as well.

The image that we are going to use, can be found by following the hub.docker link.

Summary

Make sure to study our container guide before proceeding with the configuration. Make sure to check the disclaimer and requirements sections to understand all the risks and necessary steps you might be required to do.

You can find supported architectures by following the link.

At the time, when the guide was published, eclipse-mosquitto image was available for ARM32, ARM64, and AMD64 (CHR and x86) devices. In this example, we will run it on an ARM32 architecture device → RB1100AHx4.

A very basic and quick configuration will be shown. Make sure to check mosquitto documentation page for more information about additional options and settings you can implement. If you want to use it for production, please make sure to harden the security in any way possible:

Firewall, so that access to the container is allowed only from your trusted IP addresses;
Increasing security from the mosquitto broker/server-side → use strong passwords, non-standard ports ...etc;
Use SSL MQTT.

Container configuration

Sub-menu: /container

note: container package is required.

Container mode

Enable container mode:

/system/device-mode/update container=yes

You will need to confirm the device-mode with a press of the reset button, or a cold reboot, if using container on X86.

Networking

Add veth interface for the container:

/interface/veth/add name=veth2 address=172.19.0.2/24 gateway=172.19.0.1

Create a bridge for containers and add veth to it:

/interface/bridge/add name=msqt
/ip/address/add address=172.19.0.1/24 interface=msqt
/interface/bridge/port add bridge=msqt interface=veth2

Forward TCP 1883 for non-SSL MQTT (where 192.168.88.1 is the device's LAN IP address) for testing purposes if NAT is required (optional):

/ip firewall nat add action=dst-nat chain=dstnat dst-address=192.168.88.1 dst-port=1883 protocol=tcp to-addresses=172.19.0.2 to-ports=1883

Environment variables and mounts

Per the eclipse-mosquitto docker hub, define a mount for the configuration file. We will mount not just the configuration file, but the whole folder, because, for SSL MQTT, we will need to upload certificates into the folder as well:

/container mounts add src=/mosquitto_mounted dst=/mosquitto/config name=msqt_config

Getting image

To simplify the configuration, we will get the image from an external library but you can also import it via the .tar file.

In this example, we will use the device's own storage. RB1100AHx4 has 128 MB disk space and a basic mosquitto installation should not take up more than ~15 MB.

Make sure that you have "Registry URL" set accordingly, limit RAM usage (if necessary), and set up a directory for the image:

/container/config/set registry-url=https://registry-1.docker.io tmpdir=pull

Pull image:

/container/add remote-image=library/eclipse-mosquitto:latest interface=veth2 root-dir=mosquitto mounts=msqt_config logging=yes

After running the command, RouterOS should start "extracting" the package. Check "File System" for newly created folders and monitor container status with the command /container/print.

Setting up mosquitto configuration file

To get the mosquttio.conf file, we will need to use SFTP (file transfer over SSH) protocol, so make sure that SSH service is enabled. You can also use FTP.

Open your command terminal ("CMD", as Administrator, for Windows users, or "Linux Shell or Command Terminal" for Linux users) and navigate it to the directory where you want to download the configuration file. For example, to the "Container" folder on your "Desktop":

C:\WINDOWS\system32>cd C:\Users\Administrator\Desktop\Container

C:\Users\Administrator\Desktop\Container>

Initiate SFTP to the device's IP address:

C:\Users\Administrator\Desktop\Container>sftp admin@192.168.88.1
The authenticity of host '192.168.88.1 (192.168.88.1)' can't be established.
RSA key fingerprint is SHA256:lfxxs+xMrXlvP7hiHi9ZAEZlPi6/c5US+r6J7ljhkaA.
Are you sure you want to continue connecting (yes/no/[fingerprint])?yes
Warning: Permanently added '192.168.88.1' (RSA) to the list of known hosts.
Connected to 192.168.88.1.
sftp>

Go to the mosquitto configuration file folder (use dir or ls command to see the content of the folder you are in and cd command to go to the folder of our choice). By default, the configuration is loaded from the "/mosquitto/config/mosquitto.conf", so, navigate there and use get command to download it:

sftp> cd mosquitto/mosquitto/config
sftp> dir
mosquitto.conf
sftp> get mosquitto.conf
Fetching /mosquitto/mosquitto/config/mosquitto.conf to mosquitto.conf
/mosquitto/mosquitto/config/mosquitto.conf

Open "mosquitto.conf" via your preferred text editor (notepad or any other), and just overwrite it with two lines shown below:

In this section, we will configure a basic non-SSL MQTT setup for testing purposes. Non-SSL MQTT is not secure for a production environment unless you are certain the required security/restrictions are in place.

For a production environment, topologies where the MQTT traffic can be captured/sniffed and/or topologies where the MQTT traffic is routed directly via the internet (not locally), use SSL MQTT. Check the SSL MQTT section for more information.

listener 1883
allow_anonymous true

The first line, listener 1883, will make the installation listen for incoming network connection on the specified port.
The second line, allow_anonymous true, determines whether clients that connect without providing a username are allowed to connect.

Overwrite the file using the same mosquitto.conf name.

After you have created your own custom configuration file, upload it into the mounted directory/folder "mosquitto_mounted". If you have not run the container yet, you will not have the "mosquitto_mounted" folder and you can create it manually. If you did run it (/container start 0), it should have been created automatically:

sftp> dir
mosquitto           mosquitto_mounted   pub                 pull                skins

Use SFTP from the directory where the edited mosquitto.conf file is located and put it into the mounted directory:

C:\Users\Administrator\Desktop\Container>dir
 Directory of C:\Users\Administrator\Desktop\Container

02/03/2023  12:09 PM    <DIR>          .
02/03/2023  12:09 PM    <DIR>          ..
02/03/2023  12:09 PM            40,449 mosquitto.conf
               1 File(s)         40,449 bytes
               2 Dir(s)  76,166,430,720 bytes free

C:\Users\Administrator\Desktop\Container>sftp admin@192.168.88.1
Connected to 192.168.88.1.
sftp> dir
mosquitto           mosquitto_mounted   pub                 pull                skins
sftp> cd mosquitto_mounted
sftp> put mosquitto.conf
Uploading mosquitto.conf to /mosquitto_mounted/mosquitto.conf
mosquitto.conf                                                                        100%  162    40.5KB/s   00:00

Restart the container:

[admin@MikroTik] > /container/stop 0
[admin@MikroTik] > /container/start 0

Make sure to wait for the container to stop (status=stopped should be shown after using /container/print command) before initiating it again.

Starting the container

After you make sure that the container has been added and the status changed to status=stopped after using /container/print → you can initiate it:

/container/start 0

If you have enabled container logging, you would see something like this in the Logs section:

 12:12:46 container,info,debug 1707214366: mosquitto version 2.0.18 starting
 12:12:46 container,info,debug 1707214366: Config loaded from /mosquitto/config/mosquitto.conf.
 12:12:46 container,info,debug 1707214366: Opening ipv4 listen socket on port 1883.
 12:12:46 container,info,debug 1707214366: Opening ipv6 listen socket on port 1883.
 12:12:46 container,info,debug 1707214366: mosquitto version 2.0.18 running

MQTT publish and subscribe

Sub-menu: /iot mqtt

note: iot package is required.

Add an MQTT broker:

/iot/mqtt/brokers/add name=mosquitto username=test address=172.19.0.2

Subscribe to the MQTT broker and the required topic:

/iot/mqtt/subscribe broker=mosquitto topic=test/topic

Publish a static MQTT message:

/iot/mqtt/publish broker="mosquitto" topic="test/topic" message="{\"test\":\"123\"}"

Check subscriptions for received messages:

/iot/mqtt/subscriptions/recv/print
 0 broker=mosquitto topic="test/topic" data="{"test":"123"}" 
   time=2023-07-12 10:01:40

You can also check the container logs (if enabled), to confirm the mosquitto is operational:

 12:47:28 container,info,debug 1675421248: New connection from 172.19.0.1:42240 on port 1883.
 12:47:28 container,info,debug 1675421248: New client connected from 172.19.0.1:42240 as MTD8580EC793C4 (p2, c1, k60, u'test').
 12:47:38 container,info,debug 1675421258: Client MTD8580EC793C4 disconnected.

SSL MQTT

Using non-SSL MQTT for a production environment is not secure. One can easily capture/sniff the packet exchange between the broker and the publisher and, as a result, will be able to obtain user credentials and other sensitive information.

To increase security, use SSL MQTT.

The first step is to generate the certificates. In this example, we will use a simple Root CA scenario (with no device/client certificate requirement).

Use the official mosquitto-tls user guide for the step-by-step.

Server configuration

You should have generated ca.crt (Certificate Authority file), server.crt (server certificate) and server.key (server's key):

C:\Users\Administrator\Desktop\Container>dir
 Directory of C:\Users\Administrator\Desktop\Container

07/12/2023  10:58 AM    <DIR>          .
07/12/2023  10:58 AM    <DIR>          ..
07/12/2023  10:56 AM             1,322 ca.crt
07/12/2023  10:56 AM             1,854 ca.key
07/12/2023  09:57 AM                35 mosquitto.conf
07/12/2023  10:58 AM             1,164 server.crt
07/12/2023  10:57 AM               960 server.csr
07/12/2023  10:56 AM             1,704 server.key
               6 File(s)          7,039 bytes
               2 Dir(s)  52,401,184,768 bytes free

Open mounted "mosquitto.conf" via your preferred text editor (notepad or any other), and just overwrite it with the lines shown below:

tls_version tlsv1.2
port 8883
allow_anonymous true
cafile /mosquitto/config/ca.crt
keyfile /mosquitto/config/server.key
certfile /mosquitto/config/server.crt

tls_version line sets minimal TLS version;
listener 8883, will make the installation listen for incoming network connection on the specified port;
allow_anonymous true, determines whether clients that connect without providing a username are allowed to connect;

We are using a basic SSL configuration for testing purposes. allow_anonymous true is not a secure setting for the production environment.

cafile /mosquitto/config/ca.crt line specifies a path to the CA certificate file;
keyfile /mosquitto/config/server.key line specifies a path to the server key file;
certfile /mosquitto/config/server.crt line specifies a path to the server certificate file.

Upload the certificate files, and updated SSL-ready mosquitto.conf file into the mounted folder "mosquitto_mounted":

C:\Users\Administrator\Desktop\Container>sftp admin@192.168.88.1
Connected to 192.168.88.1.
sftp> cd mosquitto_mounted
sftp> dir
mosquitto.conf
sftp> put ca.crt
Uploading ca.crt to /mosquitto_mounted/ca.crt
ca.crt                                                                                100% 1322   323.0KB/s   00:00
sftp> put server.crt
Uploading server.crt to /mosquitto_mounted/server.crt
server.crt                                                                            100% 1164   227.3KB/s   00:00
sftp> put server.key
Uploading server.key to /mosquitto_mounted/server.key
server.key                                                                            100% 1704   415.7KB/s   00:00
sftp> dir
ca.crt           mosquitto.conf   server.crt       server.key
sftp> put mosquitto.conf
Uploading mosquitto.conf to /mosquitto_mounted/mosquitto.conf
mosquitto.conf                                                                        100%  162    32.2KB/s   00:00