Having a physical access to the keyboard can simply use the Ctrl+Alt+Delete key combination to reboot the server without having to logged on, But we can prevent the use of this key combination on a production server for an accidental reboots.<\/p>\n
To disable the reboot action taken by pressing the Ctrl+Alt+Delete key combination,<\/p>\n
Comment out the following line in the file \/etc\/init\/control-alt-delete.conf<\/p>\n
$ sudo vi \/etc\/init\/control-alt-delete.conf<\/p>\n
Or<\/p>\n
$sudo gedit \/etc\/init\/control-alt-delete.conf<\/p>\n
Find line that read as follows:<\/p>\n
exec shutdown -r now \u201cControl-Alt-Delete pressed\u201d<\/p>\n
delete configuration line or comment out line by prefixing # symbol<\/p>\n
#exec shutdown -r now “Control-Alt-Delete pressed”<\/p>\n
Save and close the file.<\/p>\n
But In 16.04<\/p>\n
In the systemd world, Ctrl+Alt+Delete is handled by ctrl-alt-del.target<\/p>\n
ctrl-alt-del.target systemd starts this target whenever Control+Alt+Del is pressed on the console. Usually, this should be aliased (symlinked) to reboot.target.<\/p>\n
$systemctl mask ctrl-alt-del.target<\/p>\n
$systemctl daemon-reload<\/p>\n