SSH

SSH stands for "Secure SHell". It's great for administrating and controlling remote servers and devices.

Links

• good German tutorial and introduction: https://wiki.ubuntuusers.de/SSH/
• good tutorial for general SSH-hardening: https://stribika.github.io/2015/01/04/secure-secure-shell.html
• restrict execution of commands to predefined SSH-keys: https://cybermashup.com/2013/05/14/restrict-ssh-logins-to-a-single-command/