August 22, 1996
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Contributor: John H Terpstra

Subject:     Windows NT Domain Control & Samba
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Windows NT Server can be installed as either a plain file and print server
or as a server that participates in Domain Control. The same is true for 
OS/2 Warp Server, Digital Pathworks and other similar products, all of which
can participate in Domain Control along with Windows NT.

To many people these terms can be confusing, so let's try to clear the air.

Every Windows NT system (workstation or server) has a registry database.
The registry contains entries that describe the initialisation information
for all services (the equivalent of Unix Daemons) that run within the Windows
NT environment. The registry also contains entries that tell application
software where to find dynamically loadable libraries that they depend upon.
In fact, the registry contains entries that describes everything that anything
may need to know to interact with the rest of the system.

The Microsoft Windows NT system is structured within a security model that
says that all applications and services much authenticate themselves before
they can obtain permission from the security manager to do what they set out
to do.

The Windows NT User database also resides within the registry. This part of
the registry contains the user's security identifier, home directory, group
memberships, desktop profile, and so on.

Every Windows NT system (workstation as well as server) will have it's own
registry. Windows NT Servers that participate in Domain Security control
have a database that they share in common - thus they do NOT own a complete
and independant full registry database of their own, as do Workstations and
plain Servers.

The User database is called the SAM (Security Access Manager) database and
is used for all user authentication as well as for authentication of inter-
process authentication (ie: to ensure that the service action a user has
requested is permitted within the limits of that user's privilidges).

Windows for Workgroups, Windows 95, and Windows NT Workstations and Servers
can participate in a Domain security system that is controlled by Windows NT
servers that have been correctly configured. At most every domain will have
ONE Primary Domain Controller (PDC). It is desirable that each domain will
have at least one Backup Domain Controller (BDC).

The PDC and BDCs then participate in replication of the SAM database so that
each Domain Controlling participant will have an up to date SAM component
within it's registry.

Samba can NOT at this time function as a Domain Controller for any of these
security services, but like all other domain members can interact with the
Windows NT security system for all access authentication.

When Samba is configured with the 'security = server' option and the
'password server = Your_Windows_NT_Server_Name' option, then it will
redirect all access authentication to that server.

