Commenting out the line with a # listed below in your /etc/inittab file will disable the possibility of using
the Ctrl-Alt-Delete command to shutdown your computer. This is pretty important if you don't have the best physical security on the box.
To do this, edit the inittab file vi /etc/inittab and change the line:
ca::ctrlaltdel:/sbin/shutdown -t3 -r now
#ca::ctrlaltdel:/sbin/shutdown -t3 -r now
Now, for the change to take effect type in the following at a prompt:
[root@deep] /#/sbin/init q