To allow root to login Dragonfly BSD through SSH, you need to modify two parts in /etc/ssh/sshd_config:
......
PermitRootLogin yes
......
PasswordAuthentication yes
......
Otherwise you will bump into following error:
$ ssh root@192.168.35.195
The authenticity of host '192.168.35.195 (192.168.35.195)' can't be established.
......
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.35.195' (ECDSA) to the list of known hosts.
root@192.168.35.195: Permission denied (publickey,keyboard-interactive).