Mollyguard detects if you are logged in using ssh when you try to reboot or shutdown (unfortunatly init 6 works) a server. In this case you have to enter the hostname to proceed with the shutdown.
The installation is quite simple. Just use
apt-get install mollyguard
Afterwards you will be asked for the server-name when rebooting the server over ssh:
root@srv01:~# reboot
W: molly-guard: SSH session detected!
Please type in hostname of the machine to reboot:
If you would like to protect local sessions too, uncomment ALWAYS_QUERY_HOSTNAME=true in the config-file /etc/molly-guard/rc.