The differences between the Everyone, Users, and Authenticated Users groups aren't apparent from the group names. In a nutshell, the Everyone group is the least secure of these groups because it does indeed include everyone. The Everyone group often contains the same set of users as the Users and Authenticated Users groups. However, if you've enabled the Guest account, you'll find that users who have logged on as Guest are members of Everyone but not members of Users or Authenticated Users.
The difference between the Users and Authenticated Users groups is a bit more esoteric. After all, if all users must authenticate, aren't all users authenticated users? If they are, why do you need a different group called Authenticated Users? The answer is that not all members of the Users group are authenticated. Windows networks include the ability to have computer-to-computer connections that involve
null sessions. Computers use these sessions to exchange lists of shared folders, printers, and other network resources; workstations use null sessions to connect to domain controllers (DCs) before users authenticate to the domain. (For more information about null sessions, see the Microsoft articles "Local System Account and Null Sessions in Windows NT" at
Microsoft Help and Support default.aspx?scid=kb;en-us;q132679 and "Restricting Information Available to Anonymous Logon Users" at
Restricting information available to anonymous logon users.)
I 'll try this!