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access lists

Programming that can be added to a router's configuration that enables it to filter traffic going into and out of its interfaces.

access token

A virtual list created for a user at logon based on permissions that are assigned to the user and to groups of which that user is a member. This list is used to gain access to resources in a computer or a domain.

Accessibility Features

Tools located on the Accessories menu that can be used to magnify elements on the screen, read text, and provide other assistance for users with physical disabilities.

Accessibility Options

Settings in the Control Panel that control the keyboard, display, and sounds that a computer generates when keys are pressed. These settings can be configured to assist a user who has a physical disability.

activate

See Windows Product Activation (WPA).

Active Directory

A proprietary name given to Microsoft's X.500-compliant directory structure hosted by domain controllers. Active Directory is a distributed yet hierarchical database used to host user, computer, and group accounts as well as domain, application, and object configuration information.

active partition

The partition that contains the files that are required to boot a computer and find the operating system. This partition must always be on the first disk in the computer.

Address Resolution Protocol (ARP)

A name resolution protocol that is part of the TCP/IP protocol suite. ARP resolves an IP address to a MAC address by first checking a cache and then broadcasting when necessary.

Advanced Configuration Power Interface (ACPI)

An open industry specification that defines a flexible method of controlling power to components on a system board.

Alternate Configuration

The ability to assign an IP configuration that will be used in the event that a DHCP server is not available. Only Windows XP clients and Windows Server 2003 servers have this option.

anding

A binary calculation that the computer uses with all IP addresses and subnet masks to determine the network ID and host ID of the address.

answer files

Files that contain configuration information that is common to a group of computers being installed using an unattended installation. These files can be used to automate the installation process and answer the questions asked by the installation program.

antivirus software

Special software designed to protect computers by identifying and eradicating viruses before they have a chance to damage the computer or the data that it contains.

Appleshare IP

A service from Apple that is specifically designed to provide secure remote access for Macintosh clients to Mac OS X servers.

AppleTalk

A protocol suite designed specifically for Apple computers. Includes many protocols that Apple clients use to communicate with other Apple clients and servers.

AppleTalk File Protocol (AFP)

A protocol that allows Apple clients and servers to communicate on an Apple network or on a TCP/IP network.

archive bit

A special designation created by the system that (when set to "on") tells the backup software that the file has been modified since the last backup and therefore should be recopied.

arp cache

A list of entries on a computer for which the IP address has been recently been resolved to a MAC address. The arp cache is used first by the arp utility before it broadcasts.

Asymmetric Digital Subscriber Line (ADSL)

A communication line that can provide data rates from 1.5 to 9Mbps when receiving data but only 16 to 640Kbps when sending data.

attended installation

A type of software installation that requires a person to monitor the entire installation and occasionally choose options or enter additional information.

auditing

The process of recording a sequence of events on servers, workstations, and other networking devices. Audited events are recorded in one or more logs.

authentication

The process of verifying the identity of a user. For example, a user might be authenticated by providing the username and password combination.

authorization

The process of a person in the Enterprise Admins group giving approval for the use of a server such as a DHCP server. Without this approval, the server cannot function.

AutoCorrect

A feature of applications in Microsoft Office software that automatically corrects common typing errors or replaces text based configuration by the user.

Automatic Private IP Address (APIPA)

An automatic addressing system that can configure each client computer with a unique IP address in the 169.254.0.0 subnet. This type of addressing is typically seen when a DHCP server has failed and a client is configured to obtain an address automatically.