SSHD Configuration Hands-on Demo

An Ubuntu/deb based container with OpenSSH daemon to quickly experiment with sshd_config (aka sshd.conf) in a relatively safe Docker environment. WARNING: The container is not hardened and clear text passwords are in the Dockerfile do not expose it to public networks.

TODO: Expand make functionality by specifying what you want to have

How To

Change the config via Dockerfile, re-build, and run. You can practice Docker skills, sed, and sshd_config.

Using GNU make You will need make to do the following

make help     This help.
make build    Build the container
make run      Run container on port configured in `config.env`
make up       Build and Run container with `config.env` (Alias)
make stop     Stop and remove a running container

Example To utilize public key ssh auth generate the key

ssh-keygen -f ./my_ssh_key

Uncoment the following in the Dockerfile

COPY my_ssh_key.pub /home/sshuser/.ssh/authorized_keys
RUN chown -R sshuser:sshuser /home/sshuser/.ssh
RUN chmod 600 /home/sshuser/.ssh/authorized_keys

Build Every time something is changed in the Dockerfile you need to rebuild the container.

docker build -t sshd-ubnt .

Run

docker run -d -p2222:22 --name sshd-demo sshd-ubnt

If Docker complains that the container with the same name already exists

docker container rm sshd-demo

SSH to the Container with the password

ssh root@localhost -p 2222

SSH to the Container with the key

ssh -i ./my_ssh_key sshuser@localhost -p 2222

OpenSSH Manual

Read The Fantastic Manual: OpenSSH