Also note that their example docker config will allow anyone from the internet to connect, and even add a incoming rule in your host firewall to allow it. This

Also note that their example docker config will allow anyone from the internet to connect, and even add a incoming rule in your host firewall to allow it. This is because they don't specify the port like -p 127.0.0.1:hostport:containerport (or the analog in the docker-compose config).