docker-portfwd-server

This is a 🐳 Docker image containing an OpenSSH server that can be used for local port forwarding only.

If you want a rootless version of this image, check out dmotte/docker-portfwd-server-rootless.

📦 This image is also on Docker Hub as dmotte/portfwd-server and runs on several architectures (e.g. amd64, arm64, ...). To see the full list of supported platforms, please refer to the .github/workflows/main.yml file. If you need an architecture which is currently unsupported, feel free to open an issue.

Usage

The first things you need are host keys for the OpenSSH server and an SSH key pair for the client to be able to connect. See the usage example of dmotte/docker-portmap-server for how to get them.

In general, the use of this image is very similar to dmotte/docker-portmap-server-rootless.

Example:

docker run -it --rm \
    -v "$PWD/hostkeys:/ssh-host-keys" \
    -v "$PWD/myclientkey.pub:/ssh-client-keys/myuser/myclientkey.pub:ro" \
    -p2222:22 \
    dmotte/portfwd-server myuser:10.0.2.15:8080

See dmotte/docker-portmap-server for further details on usage; it's very similar to this one.

For a more complex example, refer to the docker-compose.yml file.

Environment variables

List of supported environment variables:

Variable	Required	Description
KEEPALIVE_INTERVAL	No (default: 30)	Value for the ClientAliveInterval option of the OpenSSH server

Development

If you want to contribute to this project, you can use the following one-liner to rebuild the image and bring up the Docker-Compose stack every time you make a change to the code:

docker-compose down && docker-compose up --build