E1

Generally used in Europe, a wide-area digital transmission scheme carrying data at 2.048Mbps. E1 transmission lines are available for lease from common carriers for private use.

E.164

1. Evolved from standard telephone numbering system, the standard recommended by ITU-T for international telecommunication numbering, particularly in ISDN, SMDS, and BISDN.
2. Label of field in an ATM address containing numbers in E.164 format.

EAP

See Extensible Authentication Protocol.

EAP Type

Authentication scheme supported in EAP.

EB

See Exabyte.

E Channel

Also known as Echo Channel. A 64Kbps ISDN control channel used for circuit switching. Specific description of this channel can be found in the 1984 ITU-T ISDN specification, but was dropped from the 1988 version. See also B Channel, D Channel, and H Channel.

ECHO

Displays messages, or turns command echoing on or off.

ECP

Acronym for “Enhanced Capabilities Port”.

Edge Device

A device that enables packets to be forwarded between legacy interfaces (such as Ethernet and Token Ring) and ATM interfaces based on information in the Data Link and Network layers. An edge device does not take part in the running of any Network layer routing protocol; it merely uses the route description protocol in order to get the forwarding information required.

EDIT

The MS-DOS screen editor which is used to create and modify ASCII formatted files, such as batch files, and the CONFIG.SYS file.

EDO

Acronym for “Extended Data Out”.

EEMS

Acronym for “Enhanced Expanded Memory Specification”.

EEOC

Acronym for “Equipment Exceeds Operator Capability”.

EEPROM

See Electrically Erasable Programmable Read-Only Memory.

EFCI

See Explicit Forward Congestion Indication.

Effective Rights

The rights that a user actually has to a file or folder. To determine a users’s effective rights, add all of the permissions that have been allowed through the user’s assignments based on that user’s username and group associations. Then subtract any permissions that have been denied the user through the username or group associations.

EFS

See Encrypting File System.

EGA

Acronym for “Enhanced Graphics Adapter”; it has 6 modes and 16 colors.

EGP (Exterior Gateway Protocol)

A reachability routing protocol used by gateways in a two-level internet. EGP is used in the Internet core system.

EIA

Acronym for “Electrical Industries Association”.

EICAR

See European Institute of Computer Anti-Virus Research.

EICAR Standard Anti-Virus Test File

This text file consists of one line of printable characters; if saved as EICAR.COM, it can be executed and displays message: “EICAR-STANDARD-ANTIVIRUS-TEST-FILE!” This provides a safe and simple way of testing the installation and behavior of anti-virus software without using a real virus.

EIGRP

See Enhanced Interior Gateway Routing Protocol.

EIP

See Ethernet Interface Processor.

EISA

Extended Industry Standard Architecture, for construction of PCs with the Intel 32-bit microprocessor.

ELAN

See Emulated LAN.

ELAP

See EtherTalk Link Access Protocol.

ElectroMagnetic Interference (EMI)

Interference caused by electromagnetic waves.

Electromagnetic Spectrum

The range of electromagnetic waves.

Electronic Mail (E-mail)

A type of client/server application that provides a routed, stored-message service between any two user e-mail accounts. E-mail accounts are not the same as user accounts, but a one-to-one relationship usually exists between them. Because all modern computers can attach to the Internet, users can send e-mail over the Internet to any location that has telephone or wireless digital service. See also Internet.

Electronically Erasable Programmable Read-Only Memory (EEPROM)

Programmed after their manufacture, these nonvolatile memory chips can be erased if necessary using electric power and reprogrammed. See also Erasable Programmable Read-Only Memory and Programmable Read-Only
Memory.

Electrostatic Discharge (ESD)

An electric shock created by a buildup of static electricity. ESD frequently damages computer components.

E-mail

Electronic mail

Emergency Repair Disk (ERD)

A disk containing the critical system files (such as portions of the Registry, the autoexec.bat file, and the config.sys file) necessary to recover your NT machine in some cases.

EMM

Expanded Memory Manager.

EMM386

Enables or disables EMM386 expanded memory support.

EMS

The Expanded Memory Specification developed by Lotus, Intel and Microsoft to enable programs to use Expanded memory and provided in DOS 5 & 6 by EMM386.EXE.

Emulated LAN (ELAN)

An ATM network configured using a client/server model in order to emulate either an Ethernet or Token Ring LAN. Multiple ELANs can exist at the same time on a single ATM network and are made up of LAN emulation client (LEC), an LAN Emulation Server (LES), a Broadcast and Unknown Server (BUS), and an LAN Emulation Configuration Server
(LECS). ELANs are defined by the LANE specification. See also LAN Emulation, LAN Emulation
Client, LAN Emulation Configuration Server, and LAN Emulation Server.

Enable Boot Logging

A Windows Advanced Options menu item that is used to create a log file that tracks the loading of drivers and services.

Enable VGA Mode

A Windows Advanced Options menu item that loads a standard VGA driver without starting the computer in Safe Mode. See also Safe Mode.

Encapsulating Security Payload (ESP)

Used to encrypt the entire payload of an IPSec packet, rendering it undecipherable by anyone other than the intended recipient. It provides confidentiality only.

Encapsulation

The technique used by layered protocols in which a layer adds header information to the protocol data unit (PDU) from the layer above. As an example, in Internet terminology, a packet would contain a header from the Physical layer, followed by a header from the Network layer (IP), followed by a header from the Transport layer (TCP), followed by the application protocol data.

Encoding

The process of translating a message from the native form of the sender to a transmittable standard form.

Encrypted Virus

An encrypted virus’s code begins with a decryption algorithm and continues with scrambled or encrypted code for the remainder of the virus. Each time it infects, it automatically encodes itself differently, so its code is never the same. Through this method, the virus tries to avoid detection by anti-virus software.

Encrypting File System (EFS)

The Windows 2000 and Windows Server 2003 technology used to store encrypted files on NTFS partitions. Encrypted files add an extra layer of security to the file system.

Encryption

Encryption codes the information sent on the network using a special algorithm and then decodes it on the other end. This technique offers varying degrees of safety, largely based on the length and complexity of the code used to encrypt the data. See also Security.

End-to-End Mode

When you use IPSec to encrypt or authenticate connections between two machines, network traffic is protected before it leaves the originating machine, and it remains secured until the receiving machine gets it and decrypts it.

Enhanced IGRP

See Enhanced Interior Gateway Routing Protocol.

Enhanced Interior Gateway Routing Protocol

An advanced routing protocol created by Cisco, combining the advantages of link-state and distance-vector protocols. Enhanced IGRP has superior convergence attributes, including high operating efficiency. See also Interior Gateway Protocol, Open Shortest Path First, and Routing Information Protocol.

Enter Key

The key that must be pressed after entering data.

Enterprise

See Forest.

Enterprise Initialization

The process of expanding the Active Directory schema, populating it with the necessary attributes and objects to support ISA Server arrays in an enterprise environment.

Enterprise Manager

See SQL Enterprise Manager.

Enterprise Network

A complex network consisting of multiple servers and multiple domains; it can be contained within one or two buildings or encompass a wide geographic area.

Entities

In a Public Key Infrastructure (PKI), parties to a transaction are known as entities, and they can be users, organizations, computers, or devices.

Environment Variables

Variables, such as the search path, that contain information available to programs and batch files about the current operating system environment.

Epoxy

See EXIPC.

EPROM

See Erasable Programmable Read-Only Memory.

ERASE

Deletes one or more files.

Erasable Programmable Read-Only Memory (EPROM)

Programmed after their manufacture, these nonvolatile memory chips can be erased if necessary using high-power light and reprogrammed. See also Electronically Erasable Programmable Read-Only Memory and Programmable Read-Only Memory.

ERD

See Emergency Repair Disk.

Error Control

An arrangement that combines error detection and error correction.

Error Correction

A method used to correct erroneous data produced during data transmission, transfer, or storage.

Error Event

An Event Viewer event type that indicates the occurrence of an error, such as a driver failure to load. See also Event Viewer.

ESF

See Extended Super Frame.

ESP

See Encapsulating Security Payload.

Ethernet

The most popular Data Link layer standard for local area networking. Ethernet implements the carrier sense multiple access with collision detection (CSMA/CD) method of arbitrating multiple computer access to the same network. This standard supports the use of Ethernet over any tpe of media including wireless broadcast. Standard Ethernet operates at 10 megabits per second. Fast Ethernet operates at 100 megabits per second. See also Data Link Layer.

Ethernet II Frame Type

Ethernet II frame types are similar to 802.3 frame types, except they contain a type field instead of a length field. This frame type can also be used with TCP/IP and AppleTalk.

Ethernet Interface Processor (EIP)

A Cisco 7000 series router interface processor card, supplying 10Mbps AUI ports to support Ethernet Version 1 and Ethernet Version 2 or IEEE 802.3 interfaces with a high-speed data path to other interface processors.

Ethernet_SNAP Frame

Ethernet_SNAP can be used for TCP/IP and AppleTalk Phase II transport protocols, as well as for IPX/SPX on Ethernet networks.

EtherTalk

A data-link product from Apple Computer that permits AppleTalk networks to be connected by Ethernet.

EtherTalk Link Access Protocol (ELAP)

In an EtherTalk network, the link-access protocol constructed above the standard Ethernet Data Link layer.

ETRN

An SMTP authentication method used by SMTP clients using dial-up connections to request their queued mail from their SMTP server.

European Institute of Computer Anti-Virus Research (EICAR)

In conjunction with several anti-virus software companies, EICAR has developed a test file for anti-virus software. See also EICAR Standard Anti-Virus Test File.

Event Sink

A piece of code that is activated by a defined trigger, such as the reception of a new message. The code is normally written in any COM-compatible programming language such as Visual Basic, VBScript, JavaScript, C, or C++. Exchange 2000 supports the following event sinks: transport, protocol, and store. Event sinks on the store can be synchronous (code executes as the event is triggered) or asynchronous (code executes sometime after the event).

Event Viewer

A Windows utility that creates logs containing a record of previous errors, warnings, and other messages from the system. Studying the event log can help you find recurring errors and discover when a problem first appeared. This information is stored in three log files: the Application log, the Security log, and the System log. See also Application Log, Security Log, and System Log.

Everyone

A Windows special group that includes anyone who could possibly access the computer. The Everyone group includes all of the users (including Guests) who have been defined on the computer.

Exabyte

A computer storage measurement equal to 1,024 petabytes.

Excess Rate

In ATM networking, traffic exceeding a connection’s insured rate. The excess rate is the maximum rate less the insured rate. Depending on the availability of network resources, excess traffic can be discarded during congestion episodes.

Exchange

Microsoft’s messaging application. Exchange implements Microsoft’s mail application programming interface (MAPI) as well as other messaging protocols such as POP, SNMP, and faxing to provide a flexible message composition and reception service. See also Electronic Mail and Fax Modems.

Exchange Conferencing Services (ECS)

A service that allows users to meet in virtual rooms on the Exchange server. Exchange Conferencing Services defines the use of a Conferencing Management Service to coordinate the room bookings and a T.120 Multipoint Control Unit (MCU) for the actual connection of clients to a conferencing session.

Exchange Virtual Server (EVS)

When clustering, you allocate different resources (such as Storage Groups) to an EVS. Upon node failure, an EVS can be moved from the failed node to one of the remaining nodes.

Exclusion

Any IP addresses within the scope range that you never want the DHCP server to automatically assign.

EXE File

An executable file; as contrasted with a document or data file. Usually, executed by double-clicking its icon or a shortcut on the desktop, or by entering the name of the program at a command prompt. Executable files can also be executed from other programs, batch files or various script files. The vast majority of known viruses infect program files. However, real-world infections by program-infecting viruses are much less common. Also known as a Program File.

EXIPC

Formerly known as Epoxy. A queuing layer that allows the IIS and store processes (Inetinfo.exe and Store.exe) to shuttle data back and forth very quickly. This is required to achieve the best possible performance between the protocols and database services on an Exchange 2000 server. Conventional applications require the processor to switch contexts when transferring data between two processes. Exchange Server 5.5 incorporated protocols such as NNTP, Post Office Protocol 3 (POP3), and Internet Messaging Access Protocol (IMAP) directly into the Store.exe process, so data transfer was very efficient. The Exchange 2000 architecture separates the protocols from the database for ease of management and to support future architectures.

EXIT

Quits the COMMAND.COM program (command interpreter).

Exit Modules

In Microsoft Certificate Services, predefined sets of instructions that tell the CA how to proceed after a request is approved. Contain rules that specify where and how a newly issued certificate is published.

EXPAND

Decompresses one or more compressed files.

Expanding a Distribution List

The process of determining the individual addresses contained within a distribution list. This process is performed by the Message Transfer Agent (MTA).

Expanded Memory

This is memory outside the conventional RAM (first 640K) that DOS uses. It can be used by software to store data and run applications.

Expansion

The procedure of directing compressed data through an algorithm, restoring information to its original size.

Expedited Delivery

An option that can be specified by one protocol layer, communicating either with other layers or with the identical protocol layer in a different network device, requiring that identified data be processed faster.

Expiration Policy

Settings that define when certain web content is no longer “fresh” and should be updated by the ISA Server.

Explicit Forward Congestion Indication (EFCI)

A congestion feedback mode permitted by ABR service in an ATM network. The EFCI may be set by any network element that is in a state of immediate or certain congestion. The destination end-system is able to carry out a protocol that adjusts and lowers the cell rate of the connection based on value of the EFCI. See also Area Border Router.

Explorer

The default shell for Windows. Explorer implements the more flexible Desktop objects paradigm rather than the Program Manager paradigm used in earlier versions of Windows. See also Desktop.

Explorer Packet

An SNA packet transmitted by a source Token Ring device to find the path through a source-route-bridged network.

Export Utility

A Microsoft Exchange utility that enables the copying (i.e., exporting) of the Exchange directory to a text file where it could be modified in a batch manner and then imported back into the directory. This utility is accessed through the Tools menu of Microsoft Exchange Administrator. See also Import Utility.

Extended Binary Coded Decimal Interchange Code (EBCDIC)

EBCDIC is the character set commonly used on large IBM mainframe computers, most IBM minicomputers, and computers from many other manufacturers. It is an 8-bit code, allowing 256 different characters. Unlike ASCII, the placement of the letters of the alphabet in EBCDIC is discontinuous. Also, there is no direct character-to-character match when converting from EBCDIC to ASCII; some characters exist in one set but not in the other. See also American Standard Code for Information Interchange, Double-Byte Character Set, ISO 10646, and Unicode.

Extended IP Access List

IP access list that filters the network by logical address, protocol field in the Network layer header, and even the port field in the Transport layer header.

Extended IPX Access List

IPX access list that filters the network by logical IPX address, protocol field in the Network layer header, or even socket number in the Transport layer header.

Extended Memory

This is memory above the 1MB memory address which DOS can use for certain operations.

Extended Partition

In basic storage, a logical drive that allows you to allocate the logical partitions however you wish. Extended partitions are created after the primary partition has been created. See also Basic Storage, Logical Drive, and Primary Partition.

Extended Setup

Used in setup mode to configure the router with more detail than Basic Setup mode. Allows multiple protocol support and interface configuration.

Extended Stored Procedure

See Stored Procedure.

Extended Super Frame (ESF)

Made up of 24 frames with 192 bits each, with the 193rd bit providing other functions including timing. This is an enhanced version of SF. See also Super Frame.

Extensible

Used to refer to a database whose schema can be modified.

Extensible Authentication Protocol (EAP)

A protocol that allows third parties to write modules that implement new authentication methods and retrofit them to fielded servers.

Extensible Storage Engine (ESE)

Formerly known as JET, the ESE is a method that defines a very low-level API to the underlying database structures in Exchange Server. Other databases, such as the Active Directory database (Ntds.dit), also use ESE. Exchange 2000 uses ESE98, whereas Exchange 5.5 and Active Directory use the older ESE97 interface. See also Joint Engine Technology (JET).

Extent

In SQL Server, the unit of allocation for tables and indexes. All SQL Server objects and data are stored in tables. Tables and indexes are organized into extents. Each extent consists of eight 8KB pages. When a table or an index requires additional storage space, a new extent is allocated.

External Command

A command DOS executes by first loading it from an external disk file.

External Interface

The connection mechanism joining your ISA Server to the Internet or other outside network that you wish to protect yourself from. This could be a second network interface card or even a modem or DSL connection.

External Trusts

Provide access to resources on a Windows NT 4 domain or forest that cannot use a forest trust.

Extinction

In reference to WINS, the Extinction interval (four days by default) controls how long a released WINS record will remain marked as “released” before it is marked as “extinct”. The extinction timeout, set to six days by default, controls how long an extinct record may remain in the database before it is removed.

Extraction

The process of copying foreign message resources, such as mailboxes, messages, etc. and putting them in a format that can be imported into Exchange. See also Source Extractors.

Extranet

A network between two or more companies that takes advantage of the low-cost internet connection rather than privately held dedicated communication lines.