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Directory service

A means of storing directory data and making it available to network users and administrators. For example, Active Directory stores information about user accounts, such as names, passwords, and phone numbers, and enables other authorized users on the same network to access this information.

Disk quota

A limitation, set by an administrator, on the amount of disk space available to a user.

Distinguished name (DN)

In the context of Active Directory, “distinguished” means the qualities that make the name distinct. The distinguished name identifies the domain that holds the object, as well as the complete path through the container hierarchy used to locate the object.

Distributed file system (DFS)

A file management system in which files can be located on separate computers but are presented to users as a single directory tree.

DNS name servers

Servers that contain information about part of the Domain Name System (DNS) database. These servers make computer names available to queries for name resolution across the Internet. Also called domain name servers.

Domain

A group of computers that share a security policy and a user account database.

Domain controller

A server in a domain that accepts account logons and initiates their authentication. In an Active Directory domain, a domain controller controls access to network resources and participates in replication.

Domain local group

A local group used on ACLs only in its own domain. A domain local group can contain users and global groups from any domain in the forest, universal groups, and other domain local groups in its own domain.

Domain name

In Active Directory, the name given to a collection of networked computers that share a common directory. On the Internet, the unique text name that identifies a specific host. A machine can have more than one domain name, but a given domain name points to only one machine. Domain names are resolved to IP addresses by DNS name servers.

Domain Name System (DNS)

A service on TCP/IP networks (the Internet included) that translates domain names into IP addresses. This allows users to employ friendly names like Finance-Server or Ourbusiness.com when querying a remote system, instead of using an IP address such as 198.45.233.59.

Dynamic Data Exchange (DDE)

Communication between processes implemented in the Windows family of operating systems. When programs that support DDE are running at the same time, they can exchange data by means of conversations. Conversations are two-way connections between two applications that transmit data alternately.

Dynamic Host Configuration Protocol (DHCP)

A TCP/IP protocol used to automatically assign IP addresses and configure TCP/IP for network clients.

Dynamic-link library (DLL)

A program module that contains executable code and data that can be used by various programs. A program uses the DLL only when the program is active, and the DLL is unloaded when the program closes.

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