su does not appear to be working

[Jason Stechschulte <jpstech@unoh.edu>]

I've encountered a strange behavior with a debian machine I have
inherited.  If I try to su to root, it always comes back with:

su: Authentication failure
Sorry.

If I look at the permissions for /bin/su, I see this:
-rwxr-xr-x
   ^
If I look at the permissions for /bin/su, on a working machine:
-rwsr-xr-x
   ^
I'm assuming this has something to do with it.  From my limited
knowledge, I believe this is called the sticky bit?  Could someone please
point me to where I can find out how to change the permissions to this
and to get a little more knowledge on the subject?

-- 
Jason Stechschulte
jpstech@unoh.edu
--
Tcl long ago fell into the Forth trap, and is now trying desperately to
extricate itself (with some help from Sun's marketing department).
             -- Larry Wall in <199705101952.MAA00756@wall.org>