restrict root access to physical console

[Mike <mike@iolo.com>]

Hello:

Is there some way to restrict root access to the physical terminal 
connected to my machine?  I recently had a server rooted and I'm starting 
from scratch with serious security in mind.  If I did restrict root access 
as above, would that successfully thwart root exploits?

Also, is there a Debian security HowTo anywhere?  I've looked and can only 
find general linux info (which is good) and RedHat specific stuff.

TIA