Anetwork host is acomputer or other device connected to acomputer network. A host may work as aserver offering information resources, services, and applications to users or other hosts on the network. Hosts are assigned at least onenetwork address.
A computer participating in networks that use theInternet protocol suite may also be called anIP host. Specifically, computers participating in theInternet are calledInternet hosts. Internet hosts and other IP hosts have one or moreIP addresses assigned to their network interfaces. The addresses are configured either manually by an administrator, automatically at startup by means of theDynamic Host Configuration Protocol (DHCP), or bystateless address autoconfiguration methods.
Network hosts that participate in applications that use theclient–server model of computing are classified asserver orclient systems. Network hosts may also function as nodes inpeer-to-peer applications, in which all nodes share and consume resources in an equipotent manner.
Inoperating systems, the termterminal host denotes atime-sharing computer ormulti-user software providing services tocomputer terminals, or a computer that provides services to smaller or less capable devices,[1] such as amainframe computer servingteletype terminals or video terminals. Other examples of this architecture include atelnet host connected to a telnet server and anxhost connected to anX Window client.
The termInternet host or justhost is used in a number ofRequest for Comments (RFC) documents that define the Internet and its predecessor, theARPANET. RFC 871 defines a host as a general-purpose computer system connected to a communications network for "... the purpose of achieving resource sharing amongst the participating operating systems..."[2]
While the ARPANET was being developed, computers connected to the network were typically mainframe computer systems that could be accessed fromdumb terminals connected viaserial ports. Since these terminals did not host software or perform computations themselves, they were not consideredhosts as they were not connected to anyIP network, and were not assigned IP addresses. User computers connected to the ARPANET at apacket-switching node were considered hosts.[3]
Anetwork node is any device participating in a network. A host is a node that participates in user applications, either as a server, client, or both. Aserver is a type of host that offers resources to the other hosts. Typically a server accepts connections fromclients who request a service function.[4]
Every network host is a node, but not every network node is a host.Network infrastructure hardware, such asmodems,Ethernet hubs, andnetwork switches are not directly or actively participating in application-level functions, and do not necessarily have a network address, and are not considered to be network hosts.