setting up dropbear as an alternative ssh daemon

install

apt install dropbear

setup (zero-conf)

generate the host keys

dropbear -s -R -EF
^C

ls -lF /etc/dropbear/dropbear_*_host_key

tune the tcp port to listen on

vi /etc/default/dropbear

DROPBEAR_PORT=2223

eventually force edwards curve host key only

DROPBEAR_EXTRA_ARGS="-r /etc/dropbear/dropbear_ed25519_host_key"

ready to go

systemd

systemctl status dropbear
systemctl enable dropbear
systemctl restart dropbear

rc-local

dropbear -s -p 2223 -j -k -r /etc/dropbear/dropbear_ed25519_host_key