Ok - so the date is now August 11, 2016. Things have changed.
1. ACP Commander in GUI mode will kill your NAS if you try to activate ssh - it will never recover - ACP commander will never see the NAS again and you will not even see the NAS in the NAS Navigator - it will be gone - do not run the automated fix
2. The /etc/sshd_config can be used without modifications - Passwords are turend on, Root login is enabled
3. The SSH host keys are missing on the NAS - which is why /usr/sbin/sshd refuses to start
4. The /etc/nas_feature is restored on each reboot, so sshd does not run on boot. Even if you change the init script. No dice.
1. Set the new admin password in the GUI and enable the first shared folder
2. Set the IP address to fixed - make sure you set the DNS (but you will have to fix this again later)
3. Generate ssh_host_key (dsa), ssh_host_dsa_key, ssh_host_rsa_key (all files are separate invocations of ssh-keygen) on a linux computer (ssh-keygen -t <type> -f <filename> -N "" - create key without a passphrase)
4. Copy the files into the primary share (share).
5. Create a file called "adjust.sh" in any text editor
5a. Add commands to move the ssh_host* files from /mnt/disk1/share to /etc
5b. Add commands to set the file mode of the /etc/ssh*key files to 600
5c. Add commands to set the owner and group of the /etc/ssh*key files to root
5d. Add the following command, replace X.X.X.X with your DNS server: echo "nameserver X.X.X.X" > /etc/resolv.conf
5e. Save adjust.sh
6. Copy adjust.sh into the primary share
7. Use ACP commander to set the root password
8. Use ACP commander to execute "sh /mnt/disk1/share/adjust.sh"
9. Use ACP commander this time (and every subsequent time) to run /usr/sbin/sshd
10. SSH into your LS210D
1-8 are a one time set of instructions.
9 and 10 are on every reboot.
You could try to use ACP commander to generate the ssh-keys in "adjust.sh" directly into /etc - YMMV.
For me, simpler steps in an more controlled environment is saner.
Also, you will want to make the adjust.sh comments be the verbose version so you can see output.
I leave it to someone else to post the files mentioned above. There is enough detail to create them.
If you want to login via ssh keys, you can set them up just as you would any other ssh server.
How are you copying the SSH keys to /etc/?
This is hilarious. I just bought another LS210D today and was searching for these instructions and found my own post.
To answer your question - please READ item 4 and 5 - it tells you to COPY the files to the NAS main share (it still works like a NAS) and then create an EXECUTABLE script called "adjust.sh" which you will place on your main share and EXECUTE via acp_commander - this will contain the command needed to move the files to the correct place.
If you are unable to execute step 4, please return your NAS. You do not requrie another paperweight.
If you are unable to execute step 5, please stop before you brick your NAS - you do not require ssh.
Hope you figure it out. The recipe is here. I'm about to follow it myself.