For SME Server, you can use the Server-Manager web interface or the command line:

signal-event reboot

or:

signal-event halt

You can shut down or restart most any Linux server at a console prompt using one of the following commands.

Reboot at specified time:

shutdown hh:mm -r

Reboot now (three equivalent options):

shutdown now -r

or

reboot

Shutdown at specified time:

shutdown hh:mm -h

Shutdown now (two equivalent options):

shutdown now -h

or

halt