How to connect to docker host from container on Windows 10 (Docker for Windows)

Short answer: in most cases, you'll need 10.0.75.1 .

In Docker for Windows, the container communicates through a vEthernet adapter called DockerNAT. To find its details, open Command Prompt and type

ipconfig

Look for an entry that looks like

Ethernet adapter vEthernet (DockerNAT):

   Connection-specific DNS Suffix  . :
   Link-local IPv6 Address . . . . . : fe80::fd29:297:4583:3ad4%4
   IPv4 Address. . . . . . . . . . . : 10.0.75.1
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Default Gateway . . . . . . . . . :

The IP address to the right of IPv4 Address is the one you need.

Note: make sure the service allows connections from outside your host. As far as that service is concerned, your docker container is a different machine. Also make sure Windows Firewall allows communication to and from the service.

One of options that allows you to connect from container to host, is to run your container with parameter

--net="host"

Example:

docker run -it --net="host" container_name

Then from container, you can connect to service on host using:

localhost:port

But in this case, you will not be able to link more containers using --link parameter.

More on this topic: http://phillbarber.blogspot.sk/2015/02/connect-docker-to-service-on-parent-host.html

UPDATE:

From version 18.03, you can use DNS name host.docker.internal, which resolves to the internal IP address used by the host.

More: https://docs.docker.com/docker-for-windows/networking/

On older versions, you can connect to service running on host Windows using IP address you get executing command ipconfig on host -> Ethernet adapter -> IPv4 Address

UPDATE As per Datz comment below, docker.for.win.localhost is working in Docker for Windows (confirmed).