Address Resolution Protocol (ARP)
A TCP/IP-based protocol that enables a sending station to determine the MAC address of the intended receiving station.
Used in IPv6, a packet that goes only to the closest interface and does not attempt to reach other interfaces with the same address.
A peer-to-peer protocol used on networks for communications between Macintosh computers.
AppleTalk Address Resolution Protocol (AARP)
An AppleTalk protocol that is used to detect the physical or MAC sublayer addresses of NICs so that they are incorporated in AppleTalk frames; when a Macintosh computer is configured for both AppleTalk and IP, AARP is used to detect physical (MAC) and IP addresses.
One copy of each frame or packet is sent to all points on a network, regardless of whether or not a node has requested it.
Challenge Handshake Authentication Protocol (CHAP)
A protocol used to encrypt passwords, such as server account passwords that are transferred over a WAN.
Classless Interdomain Routing (CIDR)
An IP addressing method that ignores address class designations and that uses a slash at the end of the dotted decimal address to show the total number of available addresses.
Common Management Interface Protocol (CMIP)
A protocol that gathers network performance data and is part of the OSI standards for network management.
A password used by network agents and the network management station so their communications cannot be easily intercepted by an unauthorized workstation or device.
Compressed Serial Line Internet Protocol (CSLIP)
An extension of the SLIP remote communications protocol that provides faster throughput than SLIP.
Data Encryption Standard (DES)
A network symmetric-key encryption standard developed by the National Institute of Standards and Technology (NIST) and ANSI.
DNS dynamic update protocol
ATCP/IP-based protocol that enables information in a DNS server to be automatically updated, such as a Windows XP Professional workstation updating its leased DHCP IP address.
A logical grouping of network resources such as computers, printers, and network devices.
Domain Name System (DNS)
A TCP/IP application protocol that resolves domain and computer names to IP addresses, and IP addresses to domain and computer names.
dotted decimal notation
An addressing technique that uses four octets, such as 10000110.11011110. 1100101.00000101, converted to decimal (for example, 134.222.101.005), to designate a network and individual hosts on the network.
Dynamic Host Configuration Protocol (DHCP)
A network protocol that provides a way for a server to automatically assign an IP address to a device on its network.
forward lookup zone
A DNS zone or table that maps computer names to IP addresses.
EtherTalk Link Access Protocol (ELAP)
An access method used on an AppleTalk network that employs CSMA/CD on a bus or star-bus hybrid topology.
File Transfer Protocol (FTP)
ATCP/IP application protocol that transfers files in bulk data streams and that is commonly used on the Internet.
host address (A) resource record
A record in a DNS forward lookup zone that consists of a computer or domain name correlated to an IPv4 (or 32-bit) address.
Hypertext Transfer Protocol (HTTP)
A protocol in the TCP/IP suite that transports information over the Internet for access by Web browsers.
Hypertext Transfer Protocol Secure (HTTPS)
A secure form of HTTP that uses Secure Sockets Layer to implement security.
Internet Corporation for Assigned Names and Numbers (ICANN)
An organization that coordinates domain naming (the Domain Name System) and guidelines for domain registration.
International Telecommunication Union (ITU)
An international standards organization that sets standards for modems, e-mail, and digital telephone systems.
Internet Protocol (IP)
A protocol used in combination with TCP or UDP that enables packets to reach a destination on a local or remote network by using dotted decimal addressing.
IP version 4 (IPv4)
The current version of IP used on most networks.
IP version 6 (IPv6)
The next version of IP after IPv4 that enables more addresses than are available through IPv4.Compared to IPv4, IPv6 also has a longer header coupled with IP extension headers for special communications needs.
IPv6 host address (AAAA) resource record
A record in a DNS forward lookup zone that consists of a computer or domain name mapped to an IPv6 (or 128-bit) address.
Internetwork Packet Exchange (IPX)
A protocol developed by Novell for use with its NetWare file server operating system.
Layer Two Tunneling Protocol (L2TP)
A protocol that transports PPP over a VPN, intranet, or the Internet. L2TP works similarly to PPTP, but unlike PPTP, L2TP uses an additional network communications standard called Layer Two Forwarding that enables forwarding on the basis of MAC addressing.
The time it takes for information to travel from the transmitting device to the receiving device.
Management Information Base (MIB)
A database of network performance information that is stored on a network agent for access by a network management station.
A transmission method in which a server divides users who request certain applications, such as multimedia applications, into groups. Each data stream of frames or packets is a one-time transmission that goes to multiple addresses, instead of sending a separate transmission to each address for each data stream.
A logical area on a network that contains a listing of named objects, such as computers, and that has the ability to perform name resolution.
NetBIOS Extended User Interface (NetBEUI)
Developed by IBM in the mid eighties, this protocol incorporates NetBIOS for communications across a network.
NetWare Link (NWLink)
A Microsoft protocol designed to emulate IPX/SPX protocol communications in Windows-based operating systems.
Managed devices that run agent software that is in contact with the network management station. Most devices connected to modern networks are agents. These include routers, repeaters, hubs, switches, bridges, PCs (via the NIC), print servers, access servers, and uninterruptible power sources (UPSs).
Network Driver Interface Specification (NDIS)
A set of standards developed by Microsoft for network drivers that enables communication between a NIC and one or more protocols.
Network File System (NFS) protocol
A TCP/IP file transfer protocol that transfers information in record streams instead of in bulk file streams.
network management station (NMS)
A computer with software that monitors networked devices that are equipped to communicate via SNMP.
Open Datalink Interface (ODI)
A driver used by Novell NetWare networks to transport multiple protocols.
Password Authentication Protocol (PAP)
A protocol that is used to authenticate an account password when accessing a server, host computer, or directory service over a WAN.
pointer (PTR) resource record
A record in a DNS reverse lookup zone that consists of an IP (version 4 or 6) address correlated to a computer or domain name.
Point-to-Point Protocol (PPP)
A widely used remote communications protocol that supports TCP/IP, NetBEUI, and IPX/SPX communications over WANs.
Point-to-Point Tunneling Protocol (PPTP)
A remote communications protocol that enables connections to networks, intranets, extranets, and VPNs through the Internet.
primary DNS server
A DNS server that is used as the main server from which to administer a zone, such as updating records in a forward lookup zone for a domain. A primary DNS server is also called the authoritative server for that zone.
Remote Network Monitoring (RMON)
A monitoring standard that uses remote network nodes, such as workstations or network devices, to perform network monitoring, including gathering information for network protocol analysis. Probes can be located on remote sections of the network, such as across bridges or routers.
Reverse Address Resolution Protocol (RARP)
A protocol used by a network node or by a software application at a node to determine its own IP address.
reverse lookup zone
A DNS server zone or table that contains records which map IP addresses to computer or domain names.
DNS servers that are on the Internet and are used to find TLDs, such as .com or .net. There are 13 root servers throughout the world that act as final authorities for finding a TLD.
secondary DNS server
A DNS server that is a backup to a primary DNS server and therefore is not authoritative.
Secure Hypertext Transfer Protocol (S-HTTP)
A secure form of HTTP that often uses Cryptographic Message Syntax and MIME Object Security Services. S-HTTP is not as commonly used as HTTPS.
Secure Shell (SSH)
A form of authentication developed for UNIX/Linux systems to provide authentication security for TCP/IP applications, such as Telnet and FTP.
Sequenced Packet Exchange (SPX)
An older Novell protocol that is used for network transport for application software, such as database information, when there is a particular need for data reliability. SPX is generally paired with IPX.
Serial Line Internet Protocol (SLIP)
Designed for UNIX environments for point-to-point communications between computers, servers, and hosts using TCP/IP.
service resource record (SRV RR)
A record in a DNS zone that is created to locate commonly used TCP/IP services. The SRV record is formatted to include information about the service that is provided by a server, the domain that is serviced by a server, and the protocol used by the server.
Signaling System 7 (SS7)
AWAN protocol for telecommunications networks that is used to set up the fastest route between two telecommunications carriers.
Simple Mail Transfer Protocol (SMTP)
A protocol in the TCP/IP suite used to transmit e-mail, such as over the Internet.
Simple Network Management Protocol (SNMP)
A protocol in the TCP/IP suite that enables computers and network equipment to gather standardized data about network performance.
The agreed-upon number of data bytes transmitted in a packet when two nodes are communicating via TCP. The amount of data can be dynamically varied, hence the sliding window, on the basis of network traffic conditions and available buffer space at each node.
start of authority (SOA) resource record
The first record in a DNS zone, it indicates if a server is authoritative for the current zone.
A subnet mask is a designated portion of an IP address that is used to indicate the class of addressing on a network and to divide a network into subnetworks as a way to manage traffic patterns.
Functioning like a virtual circuit, a TCP port enables communication between individual processes at two communicating nodes or devices. Each communicating process has its own port, and one or more ports can be used simultaneously to handle many communicating processes.
A TCP/IP application protocol that provides terminal emulation.
A device that consists of a monitor and keyboard, used to communicate with host computers that run the programs. The terminal does not have a processor to use for running programs locally.
Using software to make a computer, such as a PC, behave as though it were a terminal.
Token Talk Link Access Protocol (TLAP)
An access method used on an AppleTalk network that employs token passing and the star-ring hybrid topology.
Transmission Control Protocol (TCP)
This transport protocol, which is part of the TCP/IP suite, establishes communication sessions between networked software application processes and provides for reliable end-to-end delivery of data by controlling data flow.
Trivial File Transfer Protocol (TFTP)
A TCP/IP file transfer protocol that is designed for transfer of files that enable a diskless workstation to boot.
One copy of each frame or packet is sent to each destination point.
User Datagram Protocol (UDP)
A protocol used with IP, as an alternative to TCP, for low-overhead connectionless communications.
A partition in a DNS server that contains specific kinds of records in a lookup table, such as a forward lookup zone that contains records in a table for looking up computer and domain names to find their associated IP addresses.