Illustrated TCP/IP by Matthew G. Naugle Wiley Computer Publishing, John Wiley & Sons, Inc. ISBN: 0471196568   Pub Date: 11/01/98

Chapter 26
Introduction to the TCP/IP Standard Applications

Remote terminal emulation is provided through the TELNET protocol. For new users of the TCP/IP protocol, this is not Telenet, a packet switching technology using the CCITT standard X.25. It is pronounced TELNET. This is an application–level protocol that allows terminal emulation to pass through a network to a remote network station. TELNET runs on top of the TCP protocol and allows a network workstation to appear as a local device to a remote device (i.e., a host).

The File Transfer Protocol (FTP) is similar to TELNET in terms of control, but this protocol allows for data files to be reliably transferred on the Internet. FTP resides on top of TCP and uses it as its transport mechanism. TFTP is a simplex file transfer protocol (based on an unreliable transport layer called UDP), and is primarily used for boot loading of configuration files across an internet.

The Simple Mail Transport Protocol (SMTP) is an electronic mail system that is robust enough to run on the entire Internet system. This protocol allows for the exchange of electronic mail between two or more systems on an internet. Along with a system known as Post Office Protocol, individual users can retrieve their mail from centralized mail repositories.

The Domain Name Service (DNS) is a centralized name service that allows users to establish connections to network stations using human–readable names instead of cryptic network addresses. It provides a name–to–network address translation service. There are many other functions of DNS, including mail server name to IP address translation. Mail service would not exist if not for the DNS.

The Boot Protocol (BOOTP) and Dynamic Host Configuration Protocol (DHCP) allow for management of IP parameters on a network. These protocols do not provide for router configurations but endstation configurations. BOOTP was the original protocol that provided not only a workstation’s IP address but possibly its operating image as well. DHCP is best known for its management allocation scheme of IP addresses and is a superset of BOOTP that provides extended functions of IP as well as IP address management.