Accessing Services from Host Machine in Docker 🐳

[kristiyan22 (Kristiyan Velkov)]

If you’re running a local development server and need to access it from within a Docker container, you can use host.docker.internal a Docker Desktop feature.

For example, if your local service is running on port 3000, you can access it inside the container using:

http://host.docker.internal:3000

This is especially useful when working with microservices, API calls, or testing Front-end applications inside a containerized environment.

Learn more in my article:

Accessing Localhost service from a Docker Container

[meyay (Metin Y.)]

This is a documented feature of Docker Desktop (regardless of the os):
https://docs.docker.com/desktop/features/networking/#i-want-to-connect-from-a-container-to-a-service-on-the-host

I feel it should be mentioned in your post that it’s a Docker Desktop feature.

[rimelek (Ákos Takács)]

@kristiyan22

On Linux, you may need to manually set up host.docker.internal using:

Or as @meyay pointed out, install Docker Desktop on Linux

It works by default on macOS and Windows because you can run Linux containers on those operating systems only in a Linux virtual machine manually or using Docker Desktop, which runs a VM while you can still run the client on the host operating system. It should work the same way on Linux too when using Docker Desktop.

If you just use --add-host with the host-gateway alias, it will just point to the host gateway while Docker Desktop’s host.docker.internal domain points to the “localhost” of your host machine so you don’t have to publish the ports on the LAN IP or any Docker network gateway IP.

If you want to access the local port without Docker Desktop, you can do it as I described here

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…

[kristiyan22 (Kristiyan Velkov)]

You’re absolutely right! host.docker.internal is a documented feature of Docker Desktop, regardless of the OS. I’ll update the post to make that clearer. Thanks for pointing it out!

[kristiyan22 (Kristiyan Velkov)]

@rimelek

Or as @meyay pointed out, install Docker Desktop on Linux

It works by default on macOS and Windows because you can run Linux containers on those operating systems only in a Linux virtual machine manually or using Docker Desktop, which runs a VM while you can still run the client on the host operating system. It should work the same way on Linux too when using Docker Desktop.

If you just use --add-host with the host-gateway alias, it will just point to the host gateway while Docker Desktop’s host.docker.internal domain points to the “localhost” of your host machine so you don’t have to publish the ports on the LAN IP or any Docker network gateway IP.

If you want to access the local port without Docker Desktop, you can do it as I described here

That’s a great point! Installing Docker Desktop on Linux enables host.docker.internal to work out of the box, just like on macOS and Windows. Thanks for the clarification!

Docker Desktop’s host.docker.internal maps directly to the localhost of your host machine, making it more convenient than just using --add-host=host-gateway, which only points to the host gateway.

For those not using Docker Desktop, your alternative method for accessing local ports without it is definitely useful— good explanation!