D

Data Source Name (DSN)

The logical name used by ODBC to refer to the drive and other information required to access data. The name is use by Internet Information Server for a connection to an ODBC data source, such as a SQL Server database. To set this name, you double-click ODBC in the Control Panel.

dbWeb Administrator

The graphical user tool for Microsoft dbWeb that allows an administrator to create definition templates referred to as schemas. Schemas control how and what information from a private database is available to visitors who use the Internet to access the public Microsoft dbWeb gateway to the private database. See also schemas.

default gateway

In TCP/IP, the intermediate network device on the local network that has knowledge of the network IDs of the other networks in the Internet, so it can forward the packets to other gateways until the packet is eventually delivered to a gateway connected to the specified destination.

DHCP

See Dynamic Host Configuration Protocol.

DHCP Relay Agent

The component responsible for relaying DHCP and BOOTP (bootstrap protocol) broadcast messages between a DHCP server and a client across an IP router. See also bootstrap protocol; Dynamic Host Configuration Protocol.

DHCP server

Dynamic Host Configuration Protocol server. A server that automatically administers client TCP/IP addresses and related settings for a network.

Dial-Up Networking

A component of Windows NT and Windows 95. Enables users to connect to remote networks, such as the Internet or a private network.

directory replication

The copying of a master set of directories from a server (called an export server) to specified servers or workstations (called import computers) in the same or other domains. Replication simplifies the task of maintaining identical sets of directories and files on multiple computers, because only a single master copy of the data must be maintained. Files are replicated when they are added to an exported directory, and every time a change is saved to the file. See also Directory Replicator service.

Directory Replicator service

Replicates directories, and the files in those directories, between computers. See also directory replication.

Directory Service Manager for NetWare (DSMN)

A component of Windows NT Server. Enables network administrators to add NetWare servers to Windows NT Server domains and to manage a single set of user and group accounts that are valid at multiple servers running either Windows NT Server or NetWare.

DLL

See dynamic-link library.

DNS name

See domain name.

DNS name servers

In the DNS client/server model, the servers containing information about a portion of the DNS database, which makes computer names available to clients querying for name resolution across the Internet. See also Domain Name System.

DNS server

See DNS name servers.

DNS service

The service that provides domain name resolution. See also DNS name servers.

domain controller

In a Windows NT Server domain, refers to the computer running Windows NT Server that manages all aspects of user-domain interactions, and uses information in the directory database to authenticate users logging on to domain accounts. One shared directory database is used to store security and user account information for the entire domain. A domain has one primary domain controller (PDC) and one or more backup domain controllers (BDCs). See also backup domain controller; primary domain controller.

domain name

Part of the Domain Name System (DNS) naming structure, a domain name is the name by which a domain is known to the network. Domain names consist of a sequence of labels separated by periods. DNS domains are not Windows NT networking domains. See also Domain Name System.

Domain Name System (DNS)

Sometimes referred to as the BIND service in BSD UNIX, DNS offers a static, hierarchical name service for TCP/IP hosts. The network administrator configures the DNS with a list of host names and IP addresses, allowing users of workstations configured to query the DNS to specify remote systems by host names rather than by IP addresses. For example, a workstation configured to use DNS name resolution can use the command ping remotehost rather than ping 172.16.16.235 if the mapping for the system named "remotehost" was contained in the DNS database. DNS domains are not the same as Windows NT networking domains.

DSMN

See Directory Service Manager for NetWare.

dynamic assignment

The automatic assignment of TCP/IP properties in a changing network.

Dynamic Host Configuration Protocol (DHCP)

A protocol that offers dynamic configuration of IP addresses and related information. DHCP provides safe, reliable, and simple TCP/IP network configuration, prevents address conflicts, and helps conserve the use of IP addresses through centralized management of address allocation. Defined in RFC 1541.

dynamic-link library (DLL)

An operating system feature that enables executable routines (generally serving a specific function or set of functions) to be stored separately as files with .dll extensions and to be loaded only when needed by the program that calls them.