How to get the IP address of the docker host from inside a docker container

Question

As the title says. I need to be able to retrieve the IP address the docker hosts and the portmaps from the host to the container, and doing that inside of the container.

Answer 1

TLDR for Mac and Windows

docker run -it --rm alpine nslookup host.docker.internal

... prints the host's IP address ...

nslookup: can't resolve '(null)': Name does not resolve

Name:      host.docker.internal
Address 1: 192.168.65.2

Details

On Mac and Windows, you can use the special DNS name host.docker.internal.

The host has a changing IP address (or none if you have no network access). From 18.03 onwards our recommendation is to connect to the special DNS name host.docker.internal, which resolves to the internal IP address used by the host. This is for development purpose and will not work in a production environment outside of Docker Desktop for Mac.