Glossary
A
A-type resource record A line (record) in a computer's Domain Name System database that maps a computer's domain name (host name) to an IP address in a DNS zone.
ActiveX
™ An umbrella term for Microsoft technologies that enable developers to create interactive content for the World Wide Web.
application programming interface (API) A set of routines that an application program uses to request and carry out lower-level services performed by another component, such as the computer's operating system or a service running on a network computer.
auditing Tracking activities of users by recording selected types of events in the security log of a server or a workstation.
authentication Validation of a user's logon information. Authentication is used to enforce selective permission to access resources or to perform an operation.
B
backup domain controller (BDC) In a Windows NT Server domain, a computer running Windows NT Server that receives a copy of the domain's directory database, which contains all account and security policy information for the domain. The copy is synchronized periodically and automatically with the master copy on the primary domain controller (PDC). BDCs also authenticate user logons and can be promoted to function as PDCs as needed. Multiple BDCs can exist on a domain. See also domain controller; primary domain controller.
bandwidth In communications, the difference between the highest and lowest frequencies in a given range. For example, a telephone line accommodates a bandwidth of 3000 Hertz (Hz), the difference between the lowest (300 Hz) and highest (3300 Hz) frequencies it can carry. In computer networks, greater bandwidth indicates faster data-transfer capability and is expressed in bits per second (bps).
Basic (clear-text) authentication A method of authentication that encodes user name and password data transmissions. Basic authentication is called "clear text" because the base-64 encoding can be decoded by anyone with a freely available decoding utility. Note that encoding is not the same as encryption. See also challenge/response authentication; encryption.
BDC See backup domain controller.
bits per second (bps) The measure of speed at which data is transferred over a network.
blue screen The screen displayed when Windows NT encounters a serious error.
bootstrap protocol (BOOTP) A TCP/IP network protocol used to configure network computers. Defined by RFC 951 and RFC 1542. DHCP provides a superset of the functions provided by BOOTP. DHCP and BOOTP interoperation is defined by RFC 1534. See also Dynamic Host Configuration Protocol.
bps See bits per second.
browser See Web browser.
BSD UNIX A version of UNIX developed by Berkeley Software Design Incorporated.
bulk data encryption The encryption of all data sent over a network.
C
CGI See Common Gateway Interface.
challenge/response authentication A method of authentication in which a server uses challenge/response algorithms and Windows NT security to control access to resources. See also Basic (clear-text) authentication; encryption.
clear-text authentication See Basic (clear-text) authentication.
Common Gateway Interface (CGI) A standard interface for HTTP server application development. The standard was developed by the National Center for Supercomputing Applications.
connection-oriented protocol A network protocol with four important characteristics: the path for data packets is established in advance; the resources required for a connection are reserved in advance; a connection's resource reservation is enforced throughout the life of that connection; and when a connection's data transfer is completed, the connection is terminated and the allocated resources are freed.
D
Data Source Name (DSN) The logical name used by ODBC to refer to the drive and other information required to access data. The name is use by Internet Information Server for a connection to an ODBC data source, such as a SQL Server database. To set this name, you double-click ODBC in the Control Panel.
dbWeb Administrator The graphical user tool for Microsoft dbWeb that allows an administrator to create definition templates referred to as schemas. Schemas control how and what information from a private database is available to visitors who use the Internet to access the public Microsoft dbWeb gateway to the private database. See also schemas.
default gateway In TCP/IP, the intermediate network device on the local network that has knowledge of the network IDs of the other networks in the Internet, so it can forward the packets to other gateways until the packet is eventually delivered to a gateway connected to the specified destination.
DHCP See Dynamic Host Configuration Protocol.
DHCP Relay Agent The component responsible for relaying DHCP and BOOTP (bootstrap protocol) broadcast messages between a DHCP server and a client across an IP router. See also bootstrap protocol; Dynamic Host Configuration Protocol.
DHCP server Dynamic Host Configuration Protocol server. A server that automatically administers client TCP/IP addresses and related settings for a network.
Dial-Up Networking A component of Windows NT and Windows 95. Enables users to connect to remote networks, such as the Internet or a private network.
directory replication The copying of a master set of directories from a server (called an export server) to specified servers or workstations (called import computers) in the same or other domains. Replication simplifies the task of maintaining identical sets of directories and files on multiple computers, because only a single master copy of the data must be maintained. Files are replicated when they are added to an exported directory, and every time a change is saved to the file. See also Directory Replicator service.
Directory Replicator service Replicates directories, and the files in those directories, between computers. See also directory replication.
Directory Service Manager for NetWare (DSMN) A component of Windows NT Server. Enables network administrators to add NetWare servers to Windows NT Server domains and to manage a single set of user and group accounts that are valid at multiple servers running either Windows NT Server or NetWare.
DLL See dynamic-link library.
DNS name See domain name.
DNS name servers In the DNS client/server model, the servers containing information about a portion of the DNS database, which makes computer names available to clients querying for name resolution across the Internet. See also Domain Name System.
DNS server See DNS name servers.
DNS service The service that provides domain name resolution. See also DNS name servers.
domain controller In a Windows NT Server domain, refers to the computer running Windows NT Server that manages all aspects of user-domain interactions, and uses information in the directory database to authenticate users logging on to domain accounts. One shared directory database is used to store security and user account information for the entire domain. A domain has one primary domain controller (PDC) and one or more backup domain controllers (BDCs). See also backup domain controller; primary domain controller.
domain name Part of the Domain Name System (DNS) naming structure, a domain name is the name by which a domain is known to the network. Domain names consist of a sequence of labels separated by periods. DNS domains are not Windows NT networking domains. See also Domain Name System.
Domain Name System (DNS) Sometimes referred to as the BIND service in BSD UNIX, DNS offers a static, hierarchical name service for TCP/IP hosts. The network administrator configures the DNS with a list of host names and IP addresses, allowing users of workstations configured to query the DNS to specify remote systems by host names rather than by IP addresses. For example, a workstation configured to use DNS name resolution can use the command
ping remotehost rather than
ping 172.16.16.235 if the mapping for the system named "remotehost" was contained in the DNS database. DNS domains are not the same as Windows NT networking domains.
DSMN See Directory Service Manager for NetWare.
dynamic assignment The automatic assignment of TCP/IP properties in a changing network.
Dynamic Host Configuration Protocol (DHCP) A protocol that offers dynamic configuration of IP addresses and related information. 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. Defined in RFC 1541.
dynamic-link library (DLL) An operating system feature that enables executable routines (generally serving a specific function or set of functions) to be stored separately as files with .dll extensions and to be loaded only when needed by the program that calls them.
E
encryption The process of making information indecipherable to protect it from unauthorized viewing or use, especially during network transmission or when it is stored on a transportable magnetic medium.
enterprise network A network for a large organization that has several thousand employees (for example, more than 40,000 users) and sometimes has multiple sites.
F
file allocation table (FAT) A table or list maintained by some operating systems to keep track of the status of various segments of disk space used for file storage. Also referred to as the FAT file system. See also Windows NT File System.
File and Print Services for NetWare (FPNW) A Windows NT Server component that enables a computer running Windows NT Server to provide file and print services directly to NetWare-compatible client computers.
File Transfer Protocol (FTP) An older TCP/IP protocol used for transferring files between different computers. FTP is characterized by a required logon to the remote computer and the ability to browse directories and two-way file transfer. Most of the functions of this protocol have been subsumed by Hypertext Transport Protocol (HTTP).
firewall A system or combination of systems that enforces a boundary between two or more networks and keeps intruders out of private networks. Firewalls serve as virtual barriers to passing packets from one network to another.
FPNW See File and Print Services for NetWare.
Frame Relay A synchronous High-level Data Link Control (HDLC) protocol–based network that sends data in HDLC packets.
FTP See File Transfer Protocol.
G
Gateway Service for NetWare (GSNW) A Windows NT Server component that enables a computer running Windows NT Server to connect to NetWare servers. Creating a gateway enables computers running only Microsoft client software to access NetWare resources through the gateway.
Gopher A hierarchical system for finding and retrieving information from the Internet or an intranet. Similar to FTP, Gopher uses a menuing system and enables links to other servers.
GSNW See Gateway Service for NetWare.
H
home directory The root directory for an Internet Information Server service. The directory is accessible to the user and contains files and programs. Typically the home directory for a site contains the home page. See also home page.
home page The initial page of information for a collection of pages. The starting point for a Web site or section of a Web site is often referred to as the home page. Individuals also post pages that are called home pages.
HOSTS file A local text file in the same format as the 4.3 Berkeley Software Distribution (BSD) UNIX \etc\hosts file. This file maps host names to IP addresses. In Windows NT, this file is stored in the \Systemroot\System32\Drivers\Etc directory.
HTML See Hypertext Markup Language.
hyperlink A way of jumping to another place on the Internet. Hyperlinks usually appear in a different format from regular text. You initiate the jump by clicking the link.
Hypertext Markup Language (HTML) A simple markup language used to create hypertext documents that are portable from one platform to another. HTML files are simple ASCII text files with codes embedded (indicated by markup tags) to indicate formatting and hypertext links. The formatting language used for documents on the World Wide Web.
Hypertext Transport Protocol (HTTP) The underlying protocol by which WWW clients and servers communicate. HTTP is an application-level protocol for distributed, collaborative, hypermedia information systems. It is a generic, stateless, object-oriented protocol. A feature of HTTP is the typing and negotiation of data representation, allowing systems to be built independently of the data being transferred.
I
IANA See Internet Assigned Numbers Authority.
IDC See Internet Database Connector.
IETF See Internet Engineering Task Force.
IIS See Internet Information Server.
IMIII See Intelligent Messaging III.
IMC See Internet Mail Connector.
Inetinfo A process containing the FTP, Gopher, and HTTP services. This process is about 400K in size. In addition to the FTP, Gopher, and HTTP services, this process contains the shared thread pool, cache, logging, and SNMP services of Internet Information Server.
Integrated Services Digital Network (ISDN) A type of phone line used to enhance WAN speeds, an ISDN line can transmit at speeds of 64 or 128 kilobits per second, as opposed to standard phone lines, which typically transmit at only 9600 bits per second (bps). An ISDN line must be installed by the phone company at both the server site and the remote site. See also bits per second.
Intelligent Messaging III (IMIII) Electronic mail server software for Banyan® VINES® networks.
internet A collection of two or more private networks.
Internet The global network of networks.
Internet Assigned Numbers Authority (IANA) The central coordinator for the assignment of unique parameter values for Internet protocols. IANA is chartered by the Internet Society (ISOC) and the Federal Network Council (FNC) to act as the clearinghouse to assign and coordinate the use of numerous Internet protocol parameters. Contact IANA at
http://www.iana.org/iana/.
Internet Assistant Several Internet Assistant add-on software components are available for Microsoft Office products. Each Internet Assistant adds functionality that is relevant to creating content for the Internet. For example, Internet Assistant for Microsoft Word enables Word to create HTML documents from within Microsoft Word.
Internet Database Connector (IDC) Provides access to databases for Internet Information Server by using ODBC. The Internet Database Connector is contained in Httpodbc.dll, which is an Internet Server API DLL.
Internet Engineering Task Force (IETF) A consortium that introduces procedures for new technology on the Internet. IETF specifications are released in documents called requests for comments (RFCs). See also request for comments.
Internet Information Server (IIS) A network file and application server that supports multiple protocols. Primarily, Internet Information Server transmits information in Hypertext Markup Language (HTML) pages by using the Hypertext Transport Protocol (HTTP).
Internet Mail Connector (IMC) The Internet Mail Connector is a component of Microsoft Exchange Server that runs as a Windows NT Server service. You can use the Internet Mail Connector to exchange information with other systems that use the Simple Mail Transfer Protocol (SMTP).
Internet Network Information Center (InterNIC) The coordinator for DNS registration. To register domain names and obtain IP addresses, contact InterNIC at
http://internic.net.
Internet Protocol (IP) The part of TCP/IP that routes messages from one Internet location to another. IP is responsible for addressing and sending TCP packets over the network. IP provides a best-effort, connectionless delivery system that does not guarantee that packets arrive at their destination or that they are received in the sequence in which they were sent. See also packet.
Internet Relay Chat (IRC) A protocol that enables two or more people, each in remote locations, who are connected to an IRC server to hold real-time conversations. IRC is defined in RFC 1459.
Internet Server Application Programming Interface (ISAPI) An API for developing extensions to the Microsoft Internet Information Server and other HTTP servers that support the ISAPI interface. See also application programming interface.
Internet service provider (ISP) A company or educational institution that enables remote users to access the Internet by providing dial-up connections or installing leased lines.
InterNIC See Internet Network Information Center.
intranet A TCP/IP network that uses Internet technology. May be connected to the Internet; if connected to the Internet, intranets are usually protected by a firewall or other security device.
IP See Internet Protocol.
IP address Used to identify a node on a network and to specify routing information. Each node on the network must be assigned a unique IP address, which is made up of the network ID, plus a unique host ID assigned by the network administrator. This address is typically represented in dotted-decimal notation, of four period-delimited octets (eight bits, or one byte) consisting of up to 12 numerals (for example, 138.57.7.27). See also Dynamic Host Configuration Protocol; node.
IPX Transport protocol used in Novell NetWare networks. Also referred to as IPX/SPX. Windows NT implements IPX through NWLink.
ISDN interface card Similar in function to a modem, an ISDN card is hardware that enables a computer to connect to other computers and networks on an Integrated Services Digital Network.
ISP See Internet service provider.
K
kiosk A computer, connected to the Internet, made available to users in a commonly accessible location.
L
LAN See local area network.
leased line A high-capacity line (most often a telephone line) dedicated to network connections.
line printer daemon (LPD) A line printer daemon service on the print server receives documents (print jobs) from line printer remote (LPR) utilities running on client systems.
LMHOSTS file A local text file that maps IP addresses to the computer names of Windows NT networking computers outside the local subnet. In Windows NT, this file is stored in the \Systemroot \System32\Drivers\Etc directory.
local area network (LAN) A group of computers and other devices dispersed over a relatively limited area and connected by a communications link that enables any device to interact with any other on the network.
Local Mail Delivery Agent The component of the SMTP server that processes messages that have been received by the SMTP server and downloads the messages to the user's local computer.
loopback address The IP address 127.0.0.1, which has been specified by the Internet Engineering Task Force as the IP address to use in conjunction with a loopback driver to route outgoing packets back to the source computer. See also loopback driver.
loopback driver A network driver that allow the packets to bypass the network adapter card completely and be returned directly to the computer that is performing the test. See also loopback address.
LPD See line printer daemon.
M
Mail Server (MailSrv) A Windows NT service that sends and receives electronic mail on a TCP/IP network by using the SMTP and POP3 protocols. Also simply referred to as an SMTP server, this tool is provided in the Windows NT Server Resource Kit.
Management Information Databases (MIBs) Software that describes manageable aspects of your network that use the Simple Network Management Protocol (SNMP). The MIB files included with Windows NT can be used by third-party SNMP monitors to enable SNMP monitoring.
Microsoft dbWeb A database publishing gateway provided in the Windows NT Server Resource Kit. dbWeb can run under Internet Information Server to provide public access to private enterprise ODBC sources as specified by an administrator of the private enterprise.
The Microsoft Network (MSN) Online service that offers a free Internet site to all Internet users. Subscribers can also use proprietary information and obtain Internet access.
MIME See Multipurpose Internet Mail Extensions.
modem Modulator/demodulator. A communications device that enables a computer to transmit information over a standard telephone line.
MPR See multiprotocol routing.
multihomed system A system with multiple network adapters attached to separate physical networks.
multiport serial adapter A communications device that enables a computer to simultaneously transmit information over standard telephone lines to multiple computers. Similar to multiple modems contained in one device. See also modem.
multiprotocol routing (MPR) Enables routing over IP and IPX networks by connecting LANs or by connecting LANs to WANs. MPR refers to both the
RIP for Internet Protocol service and the
RIP for NWLink IPX/SPX Compatible Transport service.
Multipurpose Internet Mail Extensions (MIME) A standard mechanism for specifying and describing the format of Internet message bodies. MIME enables the exchanging of objects, different character sets, and multimedia in e-mail on different computer systems. Defined in RFC 1521.
MX record The MX (mail exchanger) resource record specifies a mail exchange server for a DNS domain name. A mail exchange server is a host (computer or other network device) that will either process or forward mail for the DNS domain name.
N
NCSA National Center for Supercomputing Applications is a scientific research center that is developing and implementing a national strategy to create, use, and transfer advanced computing and communication tools and information technologies. Developed one of the first Web browsers.
NDS See NetWare Directory Services.
NetBEUI A network protocol usually used in small, department-size local area networks of 1 to 200 clients. It can use Token Ring source routing as its only method of routing. See also router.
NetBIOS See network basic input/output system.
NetWare Directory Services (NDS) A NetWare service that runs on NetWare servers. The service enables the location of resources on the network.
network basic input/output system (NetBIOS) An application programming interface (API) that can be used by applications on a local area network. NetBIOS provides applications with a uniform set of commands for requesting the lower-level services required to conduct sessions between nodes on a network and to transmit information back and forth. See also application programming interface.
network card An expansion card or other device used to connect a computer to a local area network (LAN). Also called a network adapter; network adapter card; adapter card; network interface card (NIC).
network drive See shared directory.
Network File System (NFS) A service for distributed computing systems that provides a distributed file system, eliminating the need to keep multiple copies of files on separate computers.
network interface card (NIC) See network card.
Network News Transfer Protocol (NNTP) The protocol used to distribute network news messages to NNTP servers and to NNTP clients (news readers) on the Internet. NNTP provides for the distribution, inquiry, retrieval, and posting of news articles by using a reliable stream-based transmission of news on the Internet. NNTP is designed so that news articles are stored on a server in a central database, thus enabling a user to select specific items to read. Indexing, cross-referencing, and expiration of aged messages are also provided. Defined in RFC 977.
network protocols Software that enables computers to communicate over a network. The Internet protocol is TCP/IP.
NFS See Network File System.
NIC See network card.
node Any workstation, server, printer, or other device on a network that uses TCP/IP. Also called host.
NTFS See Windows NT File System.
NWLink IPX/SPX Compatible Transport A standard network protocol that supports routing, and can support NetWare client/server applications, where NetWare-aware sockets-based applications communicate with IPX\SPX sockets-based applications.
O
Open Database Connectivity (ODBC) ODBC is an application programming interface that enables applications to access data from a variety of existing data sources.
P
packet A transmission unit of fixed maximum size that consists of binary information representing both data and a header containing an ID number, source and destination addresses, and error-control data.
PDC See primary domain controller.
Peer Web Services A collection of services that enable the user of a computer running Windows NT Workstation to publish a personal Web site from the desktop. The services include the WWW service, the FTP service, and the Gopher service.
Perl Practical Extraction and Report Language. A scripting (programming) language that is frequently used for CGI scripts.
Point-to-Point Protocol (PPP) A set of industry-standard framing and authentication protocols included with Windows NT Remote Access Service to ensure interoperability with third-party remote access software. PPP negotiates configuration parameters for multiple layers of the OSI (Open Systems Interconnection) model.
Point-to-Point Tunneling Protocol (PPTP) A new networking technology that supports multiprotocol virtual private networks (VPNs). PPTP enables secure access to private networks across the Internet. With PPTP enabled, remote users can dial into an Internet service provider (ISP), or connect directly to the Internet, and all communication between the user and private network is secure.
Post Office Protocol (POP) The Post Office Protocol version 3 (POP3) is a protocol that permits a workstation to dynamically access a mail drop on a server in a useful fashion. Usually, this means that a POP3 server is used to allow a workstation to retrieve mail that an SMTP server is holding for it. POP3 is specified in RFC 1725.
POTS Acronym for Plain-Old Telephone Service. Same as public switched telephone network (PSTN). POTS is also an acronym for point of termination station, which refers to where a telephone call terminates.
primary domain controller (PDC) In a Windows NT Server domain, the computer running Windows NT Server that authenticates domain logons and maintains the directory database for a domain. The PDC tracks changes made to accounts of all computers on a domain. It is the only computer to receive these changes directly. A domain has only one PDC. See also backup domain controller; domain controller.
PTR record The pointer (PTR) resource record maps an IP address to a host name in a DNS reverse zone (those in the In-addr.arpa DNS domain).
public key cryptography A method of encrypting data transmissions to and from a server.
Q
query-by-example (QBE) A simple-to-use query language implemented on relational database management systems.
R
Remote Access Service (RAS) A service that can be used by remote clients running Microsoft Dial-Up Networking, all Microsoft RAS clients, or any third-party PPP client to dial in to a network. Remote users with RAS on a Windows NT–based computer can dial in to their networks for services such as Internet access, file and printer sharing, electronic mail, scheduling, and SQL database access.
remote procedure call (RPC) A message-passing facility that allows a distributed application to call services available on various machines in a network. Used during remote administration of computers.
replicate See directory replication.
request for comments (RFC) An official document of the IETF (Internet Engineering Task Force) that specifies the details for protocols included in the TCP/IP family. See also Internet Engineering Task Force.
RIP See Routing Information Protocol.
router A network device that manages traffic between networks or subnets. Routers match packet headers to a location on a LAN and choose the best path for the packet, optimizing network performance.
Routing Information Protocol (RIP) Enables a router to exchange routing information with a neighboring router. See also router.
RPC See remote procedure call.
S
Schema Wizard Interactive tool in dbWeb Administrator that leads a user through creation of HTML pages or through implementing an ISAPI application.
schemas Schemas control how and what information from a private database is available to visitors who use the Internet to access the public Microsoft dbWeb gateway to the private database. See also dbWeb administrator.
Secure Sockets Layer (SSL) A protocol that supplies secure data communication through data encryption and decryption. SSL enables communications privacy over networks by using a combination of public key cryptography and bulk data encryption.
Serial Line Internet Protocol (SLIP) An older industry standard that is part of Windows NT Remote Access Service to ensure interoperability with third-party remote access software.
service pack An update to the Windows NT operating system.
shared directory A directory that network users can connect to.
Simple Mail Transfer Protocol (SMTP) A protocol used on TCP/IP networks to exchange mail on the Internet between SMTP servers.
Simple Network Management Protocol (SNMP) A protocol for monitoring your network. The protocol is used by SNMP consoles and agents to communicate. In Windows NT, the SNMP service is used to get and set status information about a host on a TCP/IP network. See also Management Information Databases.
SLIP See Serial Line Internet Protocol.
SMTP See Simple Mail Transfer Protocol.
sniffer A network device that monitors packets sent over a network.
SNMP See Simple Network Management Protocol.
socket A bidirectional pipe for incoming and outgoing data between networked computers. Defined in the University of California at Berkeley Sockets API. See also Windows Sockets.
SQL See structured query language.
SQL Server A server typically running on a personal computer that uses the structured query language to query, update, and manage a relational database.
SSL See Secure Sockets Layer.
static mapping A method provided on a WINS server to assign a static (unchanging) IP address to a client.
static routing Static routing limits you to fixed routing tables, as opposed to dynamically updating the routing tables.
structured query language (SQL) A database query and programming language originally developed by IBM for mainframe computers. It is widely used for accessing data in, querying, updating, and managing relational database systems. See also SQL Server.
subnet mask A TCP/IP configuration parameter that extracts network and host configuration from an IP address. This 32-bit value enables the recipient of IP packets to distinguish the network ID portion of the IP address from the host ID.
Systems Management Server A Windows NT Server network server application that remotely manages the personal computers on a network. Systems Management Server detects computers on the network, inventories software and hardware configurations, and installs desktop applications from a central location.
T
T1 or T3 connection Standard measurements of network bandwidth.
tag file A configuration file that contains information about a corresponding file on a Gopher server or links to other servers. This information is sent to clients in response to a Gopher request.
TCP/IP See Transmission Control Protocol/Internet Protocol.
Telnet (VTP) A terminal emulation protocol for logging on to remote computers. Once referred to as Virtual Terminal Protocol (VTP). Defined in RFC 854, among others. See also Telnet Server.
Telnet Server A server that runs a Telnet service, enabling remote users to log on and run programs. See also Telnet.
TFTP See Trivial File Transfer Protocol.
token ring network A local area network formed in a ring (closed loop) topology that uses token passing as a means of regulating traffic on the line.
transforms Rules the administrator creates to add, remove, and modify domain names appended to inbound and outbound messages.
Transmission Control Protocol/Internet Protocol (TCP/IP) A set of networking protocols that provide communications across interconnected networks made up of computers with diverse hardware architectures and various operating systems. TCP/IP includes standards for how computers communicate and conventions for connecting networks and routing traffic.
Trivial File Transfer Protocol (TFTP) A file transfer protocol that transfers files to and from a remote computer running the TFTP service. TFTP was designed with less functions than FTP. Defined in RFC 1350, among others. See also File Transfer Protocol.
U
UDP See User Datagram Protocol.
Uniform Resource Locator (URL) A naming convention that uniquely identifies the location of a computer, directory, or file on the Internet. The URL also specifies the appropriate Internet protocol, such as HTTP, FTP, IRC, or Gopher.
Uninterruptible Power Supply (UPS) A battery-operated power supply connected to a computer to keep the system running during a power failure.
URL See Uniform Resource Locator.
User Datagram Protocol (UDP) A TCP complement that offers a connectionless datagram service that guarantees neither delivery nor correct sequencing of delivered packets (much like IP). See also packet.
UUENCODE (UNIX-to-UNIX Encode) A utility that converts a binary file (such as a word-processing file or a program) to text so that it can be transmitted over a network. UUDECODE (UNIX-to-UNIX Decode) is the utility used to convert the file back to its original state.
V
virtual directory An Internet Information Server directory outside the home directory. A virtual directory appears to browsers as a subdirectory of the home directory.
virtual server A computer with several IP addresses assigned to the network adapter card. This configuration makes the computer look like several servers to a browser.
Virtual Terminal Protocol (VTP) See Telnet.
W
WAIS See wide area information server.
WAN See wide area network.
Web browser A software program, such as Internet Explorer, that retrieves a document from a Web server, interprets the HTML codes, and displays the document to the user with as much graphical content as the software can supply.
Web page A World Wide Web document. Pages can contain almost anything, such as news, images, movies, and sounds.
Web server A computer equipped with the server software to respond to HTTP requests, such as requests from a Web browser. A Web server uses the HTTP protocol to communicate with clients on a TCP/IP network.
Well Known Port Number The standard port numbers used by the Internet community for well known (commonly used) services. Ports are used in TCP to name the ends of logical connections that carry long-term conversations. Well known services are defined by RFC 1060. The relationship between the well known services and the well known ports is described in RFC 1340.
wide area information server (WAIS) A network publishing system designed to help users find information over a computer network. WAIS software has four main components: the client, the server, the database, and the protocol. Discussed in RFC 1625.
wide area network (WAN) A communications network that connects geographically separated areas.
Windows Internet Name Service (WINS) A name resolution service that runs on Windows NT Server. WINS resolves NetBIOS computer names to IP addresses for WINS clients on a routed network. A WINS server handles name registrations, queries, and releases. See also Domain Name System; IP address; WINS server.
Windows NT File System (NTFS) A file system used on computers running Windows NT that enables users to set access control permissions on files and directories. NTFS supports file system recovery, extremely large storage media, long filenames, and various features for the POSIX subsystem. It also supports object-oriented applications by treating all files as objects with user-defined and system-defined attributes. See also file allocation table.
Windows NT Server Event Viewer A program provided with Windows NT that enables users to monitor system, security, and application events by viewing logs generated by Event Viewer.
Windows Sockets Windows Sockets is a Windows implementation of the widely used UC Berkeley Sockets API. The Windows Sockets API is a networking API used by programmers to create TCP/IP–based sockets applications. Microsoft TCP/IP, NWLink, and AppleTalk® protocols use this interface. Windows Sockets provides interfaces between programs and the transport protocol and works as a bidirectional pipe for incoming and outgoing data. Also called WinSock API. See also application programming interface.
WINS See Windows Internet Name Service.
WINS server A computer running Windows NT Server and the WINS service.
World Wide Web (WWW) The World Wide Web has become synonymous with the Internet. However, the World Wide Web began as a networked information project developed by Tim Berners-Lee at the European Laboratory for Particle Physics (CERN). The World Wide Web is, specifically, the software, protocols, conventions, and information that enable hypertext and multimedia publishing of resources on different computers around the world.
X
X.25 (interface card) A recommendation published by the Comite Consultatif International de Telegraphique et Telephonique (CCITT) international communications standards organization, X.25 defines the connection between a terminal and a packet-switching network. An X.25 network is a type of packet-switching network that routes units of information (packets) as specified by X.25 and is used in public data communications networks. See also packet.
X.400 system A messaging system that is compliant with the X.400 standards developed under the Comite Consultatif International de Telegraphique et Telephonique (CCITT) and the International Standards Organization (ISO).
X Windows A graphical windowing system for UNIX computers.
Z
zone data file A Domain Name System database for a zone in the DNS name space.