Clients that use a DNS server may not be able to gain
access to hosts on the Internet. When you try to configure root hints or
forwarders on the DNS server, the options for these items may be unavailable.
A DNS server behaves as a root server if there is a zone
named "." on the server. The "." zone indicates that the server is a top-level
root server. Because a root server is at the top of the DNS hierarchy, it
cannot be configured to forward and does not require root hints.
you run the Active Directory Installation Wizard (Dcpromo.exe), you can
configure a DNS server on the local computer and configure the forward lookup
zones. The wizard examines the TCP/IP configuration on the computer and
determines whether the computer is configured to use any DNS servers. If so,
the Active Directory Installation Wizard queries for the root servers. If the
computer is not configured to use any DNS servers, the wizard queries the root
servers that are listed in the Cache.dns file (the Internet root servers). If
the wizard cannot contact any root servers, it configures the local computer as
a root server and creates the "." zone.