How to install dropbear SSH server

Dropbear is a Lightweight SSH server. You can use it as openssh server alternative. Dropbear is particularly useful for embedded type Linux systems, such as wireless routers.

I have used this when I have a problem with openssh server, after an apt upgrade, openssh server stopped working. I installed dropbear and made it run on an alternative port, so I can debug openssh server problem without worrying about disconnecting from the server.

To install dropbear on Ubuntu, run

apt install dropbear

Dropbear SSH configuration

Let’s change SSH port to non default port by editing the file

vi /etc/default/dropbear

Find

DROPBEAR_PORT=22

Replace 22 with your custom port, I will use port 2222

DROPBEAR_PORT=2222

Find

NO_START=1

Replace with

NO_START=0

That completes the basic dropbear ssh configuration.

Using Dropbear SSH Server

Let’s restart dropbear service with

systemctl restart dropbear

Verify dropbear is working with command

ss -lntp | grep dropbear

As you can see dropbear is listening on port 2222. You will be able to login to the server using the custom port

ssh -p 2222 user@IP_ADDR

See SSH