The Internet Control Message Protocol (ICMP) is a supporting protocol in the Internet protocol suite. It is used by network devices, including routers, to send error messages and operational information indicating success or failure when communicating with another IP address. For example, an error is indicated when a requested service is not available or that a host or router could not be reached. ICMP differs from transport protocols such as TCP and UDP in that it is not typically used to exchange data between systems, nor is it regularly employed by end-user network applications.
The Internet protocol suite, commonly known as TCP/IP, is a framework for organizing the set of communication protocols used in the Internet and similar computer networks according to functional criteria. The foundational protocols in the suite are the Transmission Control Protocol (TCP), the User Datagram Protocol (UDP), and the Internet Protocol (IP). Early versions of this networking model were known as the Department of Defense (DoD) model because the research and development were funded by the United States Department of Defense through DARPA.
In computing, traceroute and tracert are diagnostic command-line interface commands for displaying possible routes (paths) and transit delays of packets across an Internet Protocol (IP) network.
In computer networking, the User Datagram Protocol (UDP) is one of the core communication protocols of the Internet protocol suite used to send messages to other hosts on an Internet Protocol (IP) network. Within an IP network, UDP does not require prior communication to set up communication channels or data paths.
Network address translation (NAT) is a method of mapping an IP address space into another by modifying network address information in the IP header of packets while they are in transit across a traffic routing device. The technique was originally used to bypass the need to assign a new address to every host when a network was moved, or when the upstream Internet service provider was replaced, but could not route the network's address space. It has become a popular and essential tool in conserving global address space in the face of IPv4 address exhaustion. One Internet-routable IP address of a NAT gateway can be used for an entire private network.
Berkeley sockets is an application programming interface (API) for Internet sockets and Unix domain sockets, used for inter-process communication (IPC). It is commonly implemented as a library of linkable modules. It originated with the 4.2BSD Unix operating system, which was released in 1983.
NetBIOS is an acronym for Network Basic Input/Output System. It provides services related to the session layer of the OSI model allowing applications on separate computers to communicate over a local area network. As strictly an API, NetBIOS is not a networking protocol. Operating systems of the 1980s ran NetBIOS over IEEE 802.2 and IPX/SPX using the NetBIOS Frames (NBF) and NetBIOS over IPX/SPX (NBX) protocols, respectively. In modern networks, NetBIOS normally runs over TCP/IP via the NetBIOS over TCP/IP (NBT) protocol. This results in each computer in the network having both an IP address and a NetBIOS name corresponding to a host name. NetBIOS is also used for identifying system names in TCP/IP (Windows). Simply stated, it is a protocol that allows communication of data for files and printers through the Session Layer of the OSI Model in a LAN.
STUN is a standardized set of methods, including a network protocol, for traversal of network address translator (NAT) gateways in applications of real-time voice, video, messaging, and other interactive communications.
In computer networking, the Datagram Congestion Control Protocol (DCCP) is a message-oriented transport layer protocol. DCCP implements reliable connection setup, teardown, Explicit Congestion Notification (ECN), congestion control, and feature negotiation. The IETF published DCCP as RFC 4340, a proposed standard, in March 2006. RFC 4336 provides an introduction.
NetBIOS over TCP/IP is a networking protocol that allows legacy computer applications relying on the NetBIOS API to be used on modern TCP/IP networks.
The Discard Protocol is a service in the Internet Protocol Suite defined in RFC 863. It was designed for testing, debugging, measurement, and host-management purposes.
The Echo Protocol is a service in the Internet Protocol Suite defined in RFC 862. It was originally proposed as a way to test and measure an IP network.
The Daytime Protocol is a service in the Internet Protocol Suite, defined in 1983 in RFC 867. It is intended for testing and measurement purposes in computer networks.
The Character Generator Protocol (CHARGEN) is a service of the Internet Protocol Suite defined in RFC 864 in 1983 by Jon Postel. It is intended for testing, debugging, and measurement purposes. The protocol is rarely used, as its design flaws allow for ready misuse.
inetd is a super-server daemon on many Unix systems that provides Internet services. For each configured service, it listens for requests from connecting clients. Requests are served by spawning a process which runs the appropriate executable, but simple services such as echo are served by inetd itself. External executables, which are run on request, can be single- or multi-threaded. First appearing in 4.3BSD, it is generally located at /usr/sbin/inetd. inetd is based on the (service) activator pattern
In computer networking, xinetd is an open-source super-server daemon which runs on many Unix-like systems, and manages Internet-based connectivity.
UDP hole punching is a commonly used technique employed in network address translation (NAT) applications for maintaining User Datagram Protocol (UDP) packet streams that traverse the NAT. NAT traversal techniques are typically required for client-to-client networking applications on the Internet involving hosts connected in private networks, especially in peer-to-peer, Direct Client-to-Client (DCC) and Voice over Internet Protocol (VoIP) deployments.
A network socket is a software structure within a network node of a computer network that serves as an endpoint for sending and receiving data across the network. The structure and properties of a socket are defined by an application programming interface (API) for the networking architecture. Sockets are created only during the lifetime of a process of an application running in the node.
In computer networking, a port or port number is a number assigned to uniquely identify a connection endpoint and to direct data to a specific service. At the software level, within an operating system, a port is a logical construct that identifies a specific process or a type of network service. A port at the software level is identified for each transport protocol and address combination by the port number assigned to it. The most common transport protocols that use port numbers are the Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP); those port numbers are 16-bit unsigned numbers.
Transparent Inter Process Communication (TIPC) is an inter-process communication (IPC) service in Linux designed for cluster-wide operation. It is sometimes presented as Cluster Domain Sockets, in contrast to the well-known Unix Domain Socket service; the latter working only on a single kernel.