How can a Docker container reach a service that’s only listening on localhost of the host machine?

[tituse (Tituse Rateaux)]

What is the portable, recommended way to let a container reach a service that’s listening on the host machine’s localhost?

[rimelek (Ákos Takács)]

host.docker.internal domain in Docker Desktop or

Host.docker.internal in production environment

Once again a question that inspired me to try something. Actually I have been thinking for a while about trying to implement a feature like the one in Docker desktop that lets you use host.docker.internal to connect to the localhost of the host machine. I think I have done it. So host.docker.internal is not just a hostname that directly points to the IP address of your host. It will point to the “host gateway” which can be configured but it is 172.17.0.1 by default which is the gateway of the d…