Dropbear

Dropbear is lightweight SSH server that is commonly run on routers and other low memory devices. It is also often configured to run during the boot process.

Installation

Install the dropbear package.

Configuration

Dropbear server does not have any configuration file. It is configured with command line options.

Enable/start dropbear.service.

Disable password and root logins

Edit the dropbear.service. This creates a new drop-in file. Adding content to it will override corresponding sections in main configuration.

Override the command to start Dropbear:

[Service]
ExecStart=
ExecStart=/usr/bin/dropbear -F -P /run/dropbear.pid -R -w -s

-R

Is used to generate hostkeys automatically.

-F

Is used to forbid forking into background.

-w

Is used to disallow root logins.

-s

Is used to disable password logins.

Set SSH key from GitLab

Change GitLab URL to your own.

$ mkdir -p ~/.ssh -m 0700
$ curl -sSLf https://gitlab.com/example.keys >> ~/.ssh/authorized_keys

Dropbear in Docker container

This article or section is being considered for removal.

Reason: Not specific to Arch nor Dropbear. (Discuss in Talk:Dropbear)

systemctl does not work in `archlinux` Docker container.

# systemctl start dropbear

System has not been booted with systemd as init system (PID 1). Can't operate.
Failed to connect to bus: Host is down

You need to start Dropbear manually.

# /usr/bin/dropbear -F -P /run/dropbear.pid -R -w -s