Glossary

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account lockout

A Windows security feature that locks a user account if a number of failed logon attempts occur within a specified amount of time, based on security policy lockout settings. Locked accounts cannot log on.

See also user account.

Active Directory

The Windows-based directory service. Active Directory stores information about objects on a network and makes this information available to users and network administrators. Active Directory gives network users access to permitted resources anywhere on the network using a single logon process. It provides network administrators with an intuitive, hierarchical view of the network and a single point of administration for all network objects.

See also domain.

See also forest.

See also replication.

Active Directory Service Interfaces (ADSI)

A directory service model and a set of Component Object Model (COM) interfaces. ADSI enables Windows applications and Active Directory clients to access several network directory services, including Active Directory. ADSI is supplied as a software development kit (SDK).

See also Active Directory.

Active Directory-integrated zone

A primary Domain Name System (DNS) zone that is stored in Active Directory so that it can use multimaster replication and Active Directory security features.

See also Active Directory.

See also Domain Name System (DNS).

Address Resolution Protocol (ARP)

In TCP/IP, a protocol that uses broadcast traffic on the local network to resolve a logically assigned Internet Protocol version 4 (IPv4) address to its physical hardware or media access control (MAC) layer address.

In asynchronous transfer mode (ATM), ARP is used two different ways. For classical IPv4 over ATM (CLIP), ARP is used to resolve addresses to ATM hardware addresses. For ATM LAN emulation (LANE), ARP is used to resolve Ethernet/802.3 or Token Ring addresses to ATM hardware addresses.

See also asynchronous transfer mode (ATM).

See also Internet Protocol (IP).

See also IP address.

See also packet.

See also Transmission Control Protocol/Internet Protocol (TCP/IP).

administrator

In the Windows Server 2003 family, a person who is responsible for setting up and managing local computers, stand-alone servers, member servers, or domain controllers. An administrator sets up user and group accounts, assigns passwords and permissions, and helps users with networking problems. Administrators can be members of the Administrators group on local computers or servers. A person who is a member of the Administrators group on a local computer or server has full access to that computer or server and can assign access control rights to users as necessary.

Administrators can also be members of the Domain Admins group on domain controllers and have full control over user and computer accounts residing in that domain.

See also domain.

See also domain controller.

See also user account.

APIPA

See Automatic Private IP Addressing (APIPA).

area border router (ABR)

An Open Shortest Path First (OSPF) router that is attached to multiple areas. ABRs maintain separate topological databases for each area.

See also Open Shortest Path First (OSPF).

asynchronous transfer mode (ATM)

A highspeed, connection-oriented, virtual circuit-based packet switching protocol used to transport many different types of network traffic. ATM packages data in 53-byte, fixed-length cells that can be switched quickly between logical connections on a network.

authentication

The process for verifying that an entity or object is who or what it claims to be. Examples include confirming the source and integrity of information, such as verifying a digital signature or verifying the identity of a user or computer.

See also Kerberos V5 authentication protocol.

See also trust relationship.

authenticator

A data structure used by one party to prove that another party knows a secret key. In the Kerberos authentication protocol, authenticators include timestamps, to prevent replay attacks, and are encrypted with the session key issued by the Key Distribution Center (KDC).

authorization

The process that determines what a user is permitted to do on a computer system or network.

See also authentication.

auto-static updates

The process of adding static routes to the routing table automatically. When you configure an interface to use auto-static update mode, the router sends a request to other routers and inherits routes. The routes are saved in the routing table as auto-static routes and are kept even if the router is restarted or the interface goes down. Auto-static updates are supported in Routing Information Protocol (RIP) for Internet Protocol (IP) and in RIP for Internetwork Packet Exchange (IPX), but they are not available for use with Open Shortest Path First (OSPF).

See also Open Shortest Path First (OSPF).

Automatic Private IP Addressing (APIPA)

A TCP/IP feature in Windows XP and Windows Server 2003 that automatically configures a unique IP address from the range 169.254.0.1 through 169.254.255.254 with a subnet mask of 255.255.0.0 when the TCP/IP protocol is configured for dynamic addressing and a DHCP server is not available. The APIPA range of IP addresses is reserved by the Internet Assigned Numbers Authority (IANA) for use on a single subnet, and IP addresses within this range are not used on the Internet.

See also Dynamic Host Configuration Protocol (DHCP).

See also IP address.

See also Transmission Control Protocol/Internet Protocol (TCP/IP).

autonomous system boundary router (ASBR)

A router that exchanges routing information with routers that belong to other autonomous systems. The ASBR then advertises external routes throughout the autonomous system. ASBRs can be internal or area border routers, and they might or might not be connected to the backbone.

See also area border router (ABR).

See also router.