<s>
A	O
Windows	B-General_Concept
domain	I-General_Concept
is	O
a	O
form	O
of	O
a	O
computer	B-Architecture
network	I-Architecture
in	O
which	O
all	O
user	O
accounts	O
,	O
computers	O
,	O
printers	O
and	O
other	O
security	B-General_Concept
principals	I-General_Concept
,	O
are	O
registered	O
with	O
a	O
central	O
database	O
located	O
on	O
one	O
or	O
more	O
clusters	O
of	O
central	O
computers	O
known	O
as	O
domain	B-General_Concept
controllers	I-General_Concept
.	O
</s>
<s>
Authentication	O
takes	O
place	O
on	O
domain	B-General_Concept
controllers	I-General_Concept
.	O
</s>
<s>
Starting	O
with	O
Windows	O
Server	O
2000	O
,	O
Active	B-Protocol
Directory	I-Protocol
is	O
the	O
Windows	O
component	O
in	O
charge	O
of	O
maintaining	O
that	O
central	O
database	O
.	O
</s>
<s>
The	O
concept	O
of	O
Windows	B-General_Concept
domain	I-General_Concept
is	O
in	O
contrast	O
with	O
that	O
of	O
a	O
workgroup	B-Device
in	O
which	O
each	O
computer	O
maintains	O
its	O
own	O
database	O
of	O
security	B-General_Concept
principals	I-General_Concept
.	O
</s>
<s>
Computers	O
can	O
connect	O
to	O
a	O
domain	O
via	O
LAN	B-General_Concept
,	O
WAN	O
or	O
using	O
a	O
VPN	B-Application
connection	O
.	O
</s>
<s>
Users	O
of	O
a	O
domain	O
are	O
able	O
to	O
use	O
enhanced	O
security	O
for	O
their	O
VPN	B-Application
connection	O
due	O
to	O
the	O
support	O
for	O
a	O
certification	B-Architecture
authority	I-Architecture
which	O
is	O
gained	O
when	O
a	O
domain	O
is	O
added	O
to	O
a	O
network	O
,	O
and	O
as	O
a	O
result	O
,	O
smart	O
cards	O
and	O
digital	O
certificates	O
can	O
be	O
used	O
to	O
confirm	O
identities	O
and	O
protect	O
stored	O
information	O
.	O
</s>
<s>
In	O
a	O
Windows	B-General_Concept
domain	I-General_Concept
,	O
the	O
directory	O
resides	O
on	O
computers	O
that	O
are	O
configured	O
as	O
domain	B-General_Concept
controllers	I-General_Concept
.	O
</s>
<s>
A	O
domain	B-General_Concept
controller	I-General_Concept
is	O
a	O
Windows	O
or	O
Samba	B-Language
server	O
that	O
manages	O
all	O
security-related	O
aspects	O
between	O
user	O
and	O
domain	O
interactions	O
,	O
centralizing	O
security	O
and	O
administration	O
.	O
</s>
<s>
A	O
domain	B-General_Concept
controller	I-General_Concept
is	O
generally	O
suitable	O
for	O
networks	O
with	O
more	O
than	O
10	O
PCs	B-Device
.	O
</s>
<s>
The	O
computers	O
in	O
a	O
domain	O
can	O
share	O
physical	O
proximity	O
on	O
a	O
small	O
LAN	B-General_Concept
or	O
they	O
can	O
be	O
located	O
in	O
different	O
parts	O
of	O
the	O
world	O
.	O
</s>
<s>
Where	O
PCs	B-Device
running	O
a	O
Windows	O
operating	O
system	O
must	O
be	O
integrated	O
into	O
a	O
domain	O
that	O
includes	O
non-Windows	O
PCs	B-Device
,	O
the	O
free	B-Application
software	I-Application
package	O
Samba	B-Language
is	O
a	O
suitable	O
alternative	O
.	O
</s>
<s>
Computers	O
inside	O
an	O
Active	B-Protocol
Directory	I-Protocol
domain	O
can	O
be	O
assigned	O
into	O
organizational	B-Protocol
units	I-Protocol
according	O
to	O
location	O
,	O
organizational	O
structure	O
,	O
or	O
other	O
factors	O
.	O
</s>
<s>
In	O
the	O
original	O
Windows	B-General_Concept
Server	I-General_Concept
Domain	I-General_Concept
system	O
(	O
shipped	O
with	O
Windows	B-Device
NT	I-Device
3.x/4	O
)	O
,	O
machines	O
could	O
only	O
be	O
viewed	O
in	O
two	O
states	O
from	O
the	O
administration	O
tools	O
;	O
computers	O
detected	O
(	O
on	O
the	O
network	O
)	O
,	O
and	O
computers	O
that	O
actually	O
belonged	O
to	O
the	O
domain	O
.	O
</s>
<s>
Active	B-Protocol
Directory	I-Protocol
makes	O
it	O
easier	O
for	O
administrators	O
to	O
manage	O
and	O
deploy	O
network	O
changes	O
and	O
policies	O
(	O
see	O
Group	O
Policy	O
)	O
to	O
all	O
of	O
the	O
machines	O
connected	O
to	O
the	O
domain	O
.	O
</s>
<s>
Windows	B-Device
Workgroups	I-Device
,	O
by	O
contrast	O
,	O
is	O
the	O
other	O
model	O
for	O
grouping	O
computers	O
running	O
Windows	O
in	O
a	O
networking	O
environment	O
which	O
ships	O
with	O
Windows	O
.	O
</s>
<s>
Workgroup	B-Device
computers	O
are	O
considered	O
to	O
be	O
'	O
standalone	O
 '	O
-	O
i.e.	O
</s>
<s>
there	O
is	O
no	O
formal	O
membership	O
or	O
authentication	O
process	O
formed	O
by	O
the	O
workgroup	B-Device
.	O
</s>
<s>
A	O
workgroup	B-Device
does	O
not	O
have	O
servers	O
and	O
clients	O
,	O
and	O
hence	O
represents	O
the	O
peer-to-peer	O
(	O
or	O
client-to-client	O
)	O
networking	O
paradigm	O
,	O
rather	O
than	O
the	O
centralized	O
architecture	O
constituted	O
by	O
Server-Client	O
.	O
</s>
<s>
Workgroups	B-Device
are	O
considered	O
difficult	O
to	O
manage	O
beyond	O
a	O
dozen	O
clients	O
,	O
and	O
lack	O
single	O
sign	O
on	O
,	O
scalability	O
,	O
resilience/disaster	O
recovery	O
functionality	O
,	O
and	O
many	O
security	O
features	O
.	O
</s>
<s>
Windows	B-Device
Workgroups	I-Device
are	O
more	O
suitable	O
for	O
small	O
or	O
home-office	O
networks	O
.	O
</s>
