Enabling passwordless ssh for Synology DSM version 6

Synology DSM 6.0 does not allow, let alone passwordless ssh by default. In order to enable that, so that we can have automated backup to Synology NAS, below are the steps:

1. Enable User Home in User → Advanced

 

2. Enable SSH in "Terminal & SNMP" → Terminal

3. (Recommended) Create a user, and add the user into administrator group by going to User → Create. As an example, I created a user called dbbackup.

4. Change permission of the user's home directory to 755. You can do this by ssh'ing into synology as admin, and run below command

$ ssh administrator@synology-ip

$ sudo chmod 775 /var/services/homes/dbbackup 

$ exit 

5. Ssh into synology as your new user. Edit below lines in /etc/ssh/sshd_config, and save the file.

$ ssh dbbackup@synology-ip

$ sudo vi /etc/ssh/sshd_config

...

PubkeyAuthentication yes

AuthorizedKeysFile .ssh/authorized_keys

ChallengeResponseAuthentication no

...

6. Restart sshd service

$ sudo synoservicectl --restart sshd

7. Exit from synology shell, and create a pair of ssh key in client machine, and press enter for all the questions

$ ssh-keygen

8. Transfer the public key into synology

$ ssh-copy-id dbbackup@synology-ip

9. Test you ssh connection to synology. You should be able to ssh without password into synology.

$ ssh dbbackup@synology-ip