128 lines
4.1 KiB
Markdown
128 lines
4.1 KiB
Markdown
---
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description: Networking
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keywords: windows, networking
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title: Networking features in Docker Desktop for Windows
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---
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{% assign Arch = 'Windows' %}
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Docker Desktop provides several networking features to make it easier to
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use.
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## Features
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### VPN Passthrough
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Docker Desktop networking can work when attached to a VPN. To do this,
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Docker Desktop intercepts traffic from the containers and injects it into
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{{Arch}} as if it originated from the Docker application.
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### Port Mapping
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When you run a container with the `-p` argument, for example:
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```
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$ docker run -p 80:80 -d nginx
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```
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Docker Desktop makes whatever is running on port 80 in the container (in
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this case, `nginx`) available on port 80 of `localhost`. In this example, the
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host and container ports are the same. What if you need to specify a different
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host port? If, for example, you already have something running on port 80 of
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your host machine, you can connect the container to a different port:
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```
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$ docker run -p 8000:80 -d nginx
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```
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Now, connections to `localhost:8000` are sent to port 80 in the container. The
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syntax for `-p` is `HOST_PORT:CLIENT_PORT`.
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### HTTP/HTTPS Proxy Support
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See [Proxies](index.md#proxies).
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## Known limitations, use cases, and workarounds
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Following is a summary of current limitations on the Docker Desktop for {{Arch}}
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networking stack, along with some ideas for workarounds.
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### There is no docker0 bridge on {{Arch}}
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Because of the way networking is implemented in Docker Desktop for {{Arch}}, you cannot
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see a `docker0` interface on the host. This interface is actually within the
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virtual machine.
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### I cannot ping my containers
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Docker Desktop for Windows can't route traffic to Linux containers. However, you can
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ping the Windows containers.
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### Per-container IP addressing is not possible
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The docker (Linux) bridge network is not reachable from the Windows host.
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However, it works with Windows containers.
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### Use cases and workarounds
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There are two scenarios that the above limitations affect:
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#### I want to connect from a container to a service on the host
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The host has a changing IP address (or none if you have no network access). We recommend that you connect to the special DNS name
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`host.docker.internal` which resolves to the internal IP address used by the
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host. This is for development purpose and will not work in a production environment outside of Docker Desktop for Windows.
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You can also reach the gateway using `gateway.docker.internal`.
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If you have installed Python on your machine, use the following instructions as an example to connect from a container to a service on the host:
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1. Run the following command to start a simple HTTP server on port 8000.
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`python -m http.server 8000`
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If you have installed Python 2.x, run `python -m SimpleHTTPServer 8000`.
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2. Now, run a container, install `curl`, and try to connect to the host using the following commands:
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```console
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$ docker run --rm -it alpine sh
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# apk add curl
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# curl http://host.docker.internal:8000
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# exit
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```
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#### I want to connect to a container from Windows
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Port forwarding works for `localhost`; `--publish`, `-p`, or `-P` all work.
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Ports exposed from Linux are forwarded to the host.
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Our current recommendation is to publish a port, or to connect from another
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container. This is what you need to do even on Linux if the container is on an
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overlay network, not a bridge network, as these are not routed.
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The command to run the `nginx` webserver shown in [Getting Started](index.md#explore-the-application)
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is an example of this.
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```bash
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$ docker run -d -p 80:80 --name webserver nginx
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```
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To clarify the syntax, the following two commands both publish container's port `80` to host's port `8000`:
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```bash
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$ docker run --publish 8000:80 --name webserver nginx
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$ docker run -p 8000:80 --name webserver nginx
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```
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To publish all ports, use the `-P` flag. For example, the following command
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starts a container (in detached mode) and the `-P` flag publishes all exposed ports of the
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container to random ports on the host.
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```bash
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$ docker run -d -P --name webserver nginx
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```
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See the [run command](../engine/reference/commandline/run.md) for more details on
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publish options used with `docker run`.
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