docker eclipse-mosquitto run only on localhost

Question

I want to use docker eclipse-mosquitto just for communication on a local machine. Which settings do I need for mosquitto.conf to make the mosquitto broker only visible on localhost but not from outside? Since a second mosquitto is running, port 1883 is blocked and I'm using port 1884.

This is what I have:

port 1884
bind_address 127.0.0.1

is visible from outside.

port 1884
bind_address localhost

gives error Error: Address not available.

Binding to docker-ip

port 1884
bind_address 172.17.0.1

gives error Error: Address not available.

What can I do?

Answer 1

Your answer is the wrong approach, you should only really be using --network="host" for things that need to open raw sockets or receive broadcast messages from the local network.

The correct answer is to not use the bind_address option in the mosquitto.conf file and use the docker -p option to do the port mapping correctly (docs).

e.g.

docker run exec -rm -p 127.0.0.1:1884:1884/tcp mosquitto

Here the -p 127.0.0.1:1884:1884 maps port 1884 in the container to port 1884 bound to the loopback ip (127.0.0.1) on the host.

Answer 2

Ok, solved it myself:

Running docker with additional option --network="host" and than in mosquitto.conf:

port 1884
bind_address 127.0.0.1

does the job.