A quick tip for Synology enthusiasts ;-).
If you are using SSH to connect to your Synology NAS, you'll notice that only the
admin user are allowed by default. If you try to login as another user, the terminal says that "permission is denied" and then cuts the connection. I wouldn't really call this desired behaviour.
Luckily, this issue is easy to overcome… Just edit
/etc/passwd with your favorite (command line) text editor. You should replace
/bin/ash for users you want allow secure shell access. Save the file, quit the editor and… "SSH like a boss" (with your wee custom user)!