Red Hat ENTERPRISE LINUX 4.5.0 Reference Manual page 281

A domain controller in Windows NT is functionally similar to a Network Information Service (NIS)
server in a Linux environment. Domain controllers and NIS servers both host user/group
information databases as well as related services. Domain controllers are mainly used for
security, including the authentication of users accessing domain resources. The service that
maintains the user/group database integrity is called the Security Account Manager (SAM). The
SAM database is stored differently between Windows and Linux Samba-based systems,
therefore SAM replication cannot be achieved and platforms cannot be mixed in a PDC/BDC
environment.
In a Samba environment, there can be only one PDC and zero or more BDCs.
Important
Samba cannot exist in a mixed Samba/Windows domain controller environment
(Samba cannot be a BDC of a Windows PDC or vice versa). Alternatively,
Samba PDCs and BDCs can coexist.
3.3.1. Primary Domain Controller (PDC) using
The simplest and most common implementation of a Samba PDC uses the
database backend. Planned to replace the aging
improvements that are explained in more detail in
Databases ". The
passdb backend
[global]
workgroup = DOCS
netbios name = DOCS_SRV
passdb backend = tdbsam
security = user
add user script = /usr/sbin/useradd -m %u
delete user script = /usr/sbin/userdel -r %u
add group script = /usr/sbin/groupadd %g
delete group script = /usr/sbin/groupdel %g
add user to group script = /usr/sbin/usermod -G %g %u
add machine script = \
/usr/sbin/useradd -s /bin/false -d /dev/null \
-g machines %u
# The following specifies the default logon script
# Per user logon scripts can be specified in the user
# account using pdbedit
logon script = logon.bat
# This sets the default profile path.
# Set per user paths with pdbedit
logon path = \\%L\Profiles\%U
logon drive = H:
logon home = \\%L\%U
domain logons = Yes
os level = 35
preferred master = Yes
smbpasswd
Section 5, " Samba Account Information
directive controls which backend is to be used for the PDC.
Domain Controller
tdbsam
tdbsam
backend, has numerous
tdbsam
password
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