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Access control entry (ACE)

An entry in an access control list (ACL) that defines the level of access for a user or group.

Access control list (ACL)

A set of data associated with a file, directory, or other resource that defines the permissions users or groups have for accessing it. In Active Directory, the ACL is a list of access control entries (ACEs) stored with the object it protects. In Microsoft Windows Server 2003, Windows 2000, and Windows NT, an ACL is included in a data structure called a security descriptor.

Access point

Hardware device or software that acts as a communication hub for users of a wireless device to connect to a wired LAN.

Account lockout

A security feature that disables a user account if failed logons exceed a specified number in a specified period of time. Locked accounts can’t log on and must be unlocked by an administrator.

Active Directory

Beginning in Microsoft Windows 2000 Server and continuing in Windows Server 2003, Active Directory replaces the Windows NT collection of directory functions with an integrated implementation that includes DNS, DHCP, LDAP, and Kerberos.

ActiveX

A loosely defined set of technologies that allows software components to interact with each other in a networked environment.

ActiveX component

Reusable software component that adheres to the ActiveX specification and can operate in an ActiveX-compliant environment.

Address

A precise location where a piece of information is stored in memory or on disk. Also, the unique identifier for a node on a network. On the Internet, the code by which an individual user is identified. The format is username@hostname, where username is your user name, logon name, or account number; and hostname is the name of the computer or Internet provider you use. The host name might be a few words strung together with periods.

Address Resolution Protocol (ARP)

A TCP/IP and AppleTalk protocol that provides IP-address-to-MAC (media access control) address resolution for IP packets.

Administrative credentials

Logon information used to verify the identity of a member of the administrators group.

Advanced Configuration Power Interface (ACPI)

An industry specification defining power management on a range of computer devices. ACPI compliance is necessary for devices to take advantage of Plug and Play and power management capabilities.

Allocation unit

The smallest unit of managed space on a hard disk or logical volume. Also called a cluster.

Anonymous FTP

A way to use the FTP program to log on to another computer to copy files when you don’t have an account on that computer. When you log on, type anonymous as the user name and your address as the password. This gives you access to publicly available files. See File Transfer Protocol (FTP).

AppleTalk

Local area network architecture built into Macintosh computers to connect them with printers and other devices. A network with a Windows Server 2003 server and Macintosh clients can function as an AppleTalk network with the use of AppleTalk network integration (formerly Services for Macintosh).

Associate

To connect files having a particular extension to a specific program. When you double-click a file with the extension, the associated program is launched and the file you clicked is opened. In the Windows operating system, associated file extensions are usually called registered file types.

Asynchronous Transfer Mode (ATM)

A network technology based on sending data in cells or packets of a fixed size. It is asynchronous in that the transmission of cells containing information from a particular user isn’t necessarily periodic.

Attribute

A characteristic. In Windows file management, it is information that shows whether a file is read-only, hidden, compressed, encrypted, ready to be backed up (archived), or should be indexed.

Audit policy

Defines the type of security events to be logged. It can be defined on a server or an individual computer.

Authentication

Verification of the identity of a user or computer process. In Windows Server 2003, Windows 2000, and Windows NT, authentication involves comparing the user’s security identifier (SID) and password to a list of authorized users on a domain.

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