Networking: A Beginner's Guide
You can configure Windows Server 2008 in one of three modes to support either
domains or workgroups, as follows:
Domain controllers hold the domain's Active Directory information and
authenticate users and access to resources. Most Windows Server 2008
networks have at least one domain and therefore need at least one domain
Member servers are part of a domain, but do not hold a copy of the Active
Stand-alone servers do not participate in a domain, but instead participate in a
Earlier versions of Windows servers (NT and 2000) needed to be designated as
either primary domain controllers (PDCs) or backup domain controllers (BDCs). The
PDC performed all administrative tasks, and the BDCs simply kept read-only copies of
the domain information to continue authenticating security on the network in case the
Newer Windows servers, such as those running Windows Server 2008, simplify
matters, so that all Windows Server 2008 domain controllers are just that--domain
controllers. Each domain controller holds a copy of the Active Directory data and can
perform all the functions of the other domain controllers. Windows Server 2008 uses
the concept of multimaster domain controllers, which all seamlessly operate the same way
as the other domain controllers.
Except in the smallest of networks, it's a very good idea to have two domain controllers. This
way, all of your domain information is preserved and available to the network should one of the
domain controllers crash. Domain information is automatically synchronized between the available
Per Seat or Per Server?
Yet another important choice to make when installing Windows Server 2008 is how the
server will manage its Client Access Licenses (CALs). Windows Server 2008 supports
two different ways of managing CALs:
Per-server licensing assigns the CALs to the server, which will allow only as
many connections from computers as there are installed CALs on that server.
Per-seat licensing requires purchasing a CAL for each of your client computers,
which gives them the right to access as many Windows servers as they wish;
the servers will not monitor the number of connections.