Microsoft Internet Security and Acceleration Server 2000

D

data filter
An application filter that monitors content, as in a check for viruses, and that can also modify content.
data packet
A sequence of binary digits, including data and control signals, that is transmitted and switched as a composite whole. The data, control signals, and, possibly, error control information are arranged in a specific format.
Data Source Name (DSN)
The logical name that allows a connection to an ODBC data source, such as a SQL Server database.
demand-dial connectivity
A process used by Autodial to perform on-demand dialout connections either to an Internet service provider or to a corporate office from a branch office.
DHCP
See Dynamic Host Configuration Protocol (DHCP).
DHCP relay agent
The component that relays DHCP and BOOTP broadcast messages between a DHCP server and a client across an IP router.
dial-up networking
A component of Windows 2000 and Windows 95/98 that enables users to connect to remote networks, such as the Internet or an internal network, over a telephone line.
discretionary access-control list (DACL)
A list that is controlled by the owner of an object and that specifies the access that particular users or groups can have to the object.
distributed caching
The caching of Internet objects in an array or chain of ISA computers, providing load balancing and fault tolerance. Client requests are sent through the array, to upstream ISA computers, or any combination thereof.
DNS
See Domain Name System (DNS).
DNS spoofing
The practice of assuming the DNS name of another system either by corrupting a name-service cache or by compromising a domain-name server for a valid domain.
domain filtering
Controlling access to specific Internet sites by denying or granting permission based on the Internet computer's domain name or friendly name.
domain name
The computer name that substitutes for a network IP address. For example, www.microsoft.com instead of the IP address 157.45.60.81. Also called the friendly name. See also Domain Name System (DNS).
Domain Name System (DNS)
A protocol and computer-naming hierarchy used throughout the Internet to map computer IP addresses to their domain names. DNS is sometimes referred to as the BIND service.
downstream/upstream routing
The routing of a response from one ISA computer to another ISA computer. Client computers connecting to an ISA computer are always downstream. A request from a client computer always flows upstream to ISA computers until the requested item is found, whether it is in the cache of an ISA computer or from the Internet. ISA sends the response downstream to the client computer.
driver
A software component that allows a computer to send and receive information to and from a hardware device.
DSN
See Data Source Name (DSN).
dual-homed
Having connections to two separate physical networks. Each ISA computer in an array has both an internal and external network adapter for Internet connectivity. The internal adapter connects to the internal network. The external adapter connects to the Internet.
dynamic addressing
The automatic assignment of IP addresses in a changing network.
dynamic filters
Dynamic filters are automatically started by the Firewall service, Web proxy, or SOCKS proxy service. This feature allows the ISA services to automatically open and close communication ports on the external interface when transmission of packets is needed.
Dynamic Host Configuration Protocol (DHCP)
A protocol that offers dynamic assignment of IP addresses and related information for temporarily connected network users. 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.