Active Directory Logical Structure

DNS and the Internet

The Internet is a TCP/IP network. Every computer on the Internet or on any other TCP/IP network has an IP address. DNS locates TCP/IP hosts by resolving the computer names that end users understand to the IP addresses that computers understand. For example, the computer name DC1.reskit.com is resolved to the IP address 172.16.44.1. The addresses on the Internet are managed by using the globally distributed DNS database, but DNS can also be implemented locally to manage addresses within private TCP/IP networks. To create a presence on the Internet, it is recommended that an organization register its domain name with an Internet DNS registration agency so that other computers on the Internet can locate its servers, and vice versa. Registration is important to ensure that another organization does not use the same domain name.

Because DNS is the organizational structure of the Internet, the entire Internet is a single global namespace that is subdivided into a set of top-level domains that are then further subdivided into second-level domains. The root of the Internet domain namespace is managed by an Internet authority that is responsible for delegating administrative responsibility for the top-level domains of the DNS namespace and for registering second-level domain names. The top-level domains are the basic domain categories, such as commercial (.com), educational (.edu), and governmental (.gov). Second-level domains represent namespaces that are formally registered to individuals and to institutions and, thus, provide an Internet presence for these individuals and institutions. Their presence is supported by pointers in the relevant top-level domains to DNS servers that are authoritative for an individual's or organization's root domain; for example, name servers that are authoritative for the .com DNS database contain pointers to DNS name servers in the root domain of the private domain (reskit.com). These DNS pointers enable other domains to use the Internet to find the reskit.com domain. Similarly, DNS servers that are authoritative for the root domain for an individual or organization provide pointers to all DNS servers in child domains of the root domain, and so on down the hierarchy. DNS name servers on a private network likewise can contain pointers to Internet name servers if you want to be able to locate other domains on the Internet.

For more information about DNS and the Internet, see "Introduction to DNS" in the TCP/IP Core Networking Guide. For more information about top-level and second-level domains, see Windows 2000 Server Help.