I can't remember but I'm pretty sure you have to install an add on for it or something. I guarantee 5 minutes of googling will reveal the answer. That's how I figured it out.

Ironic that this is the top result on Google.

I am on v6.3.2 and ssh supposed to be enabled by default. However, when I tried to ssh, I got 'connection refused'

# ps aux | grep sshd  
root     23907  0.0  0.0   9640  1848 pts/1    S+   21:26   0:00 grep sshd   

All the files in /boot/config/ssh/ have 0 bytes, but the sshd_config

unRAID v6 and later automatically sets up the SSH keys necessary for SSH access For terminal access from a Windows station, use the PuTTY instructions below to install, configure, and set up the SSH connection

can you check to see if sshd is running?

what would be the command for that? I tried to use service, and got command not found.

I ran this command

# ps aux | grep sshd  
root     23907  0.0  0.0   9640  1848 pts/1    S+   21:26   0:00 grep sshd  

SSH should be enabled by default. However, the only account that can connect (by default) is the root user. :)

So if you do get it running, keep that in mind :)

I tried to ssh using root, and got connection refused. I nmap'd my server and it says it was closed.

Settings > Management Access > Use SSH > Yes