HyperText Transfer Protocol (HTTP) the underlying protocol used by the World Wide Web. HTTP defines how messages are formatted and transmitted, and what actions Web servers and browsers should take in response to various commands. For example, when you enter a URL in your browser, this actually sends an HTTP command to the Web server directing it to fetch and transmit the requested Web page.
The other main standard that controls how the World Wide Web works is HyperText Markup Language Protocol (HTML) which covers how Web pages are formatted and displayed.
HTTP is called a stateless protocol because each command is executed independently, without any knowledge of the commands that came before it. This is the main reason that it is difficult to implement Web sites that react intelligently to user input. This shortcoming of HTTP is being addressed in a number of new technologies, including ActiveX, Java, JavaScript and cookies.
File Transfer Protocol (FTP) the protocol for exchanging files over the Internet. FTP works in the same way as HTTP for transferring Web pages from a server to a user's browser and SMTP for transferring electronic mail across the Internet in that, like these technologies, FTP uses the Internet's TCP/IP protocols to enable data transfer.
FTP is most commonly used to download a file from a server using the Internet or to upload a file to a server (e.g., uploading a Web page file to a server).
Telnet is a terminal emulation program for TCP/IP networks such as the Internet. The Telnet program runs on a computer and connects the computer to a server on the network. Commands entered through the Telnet program will be executed as if they were entered directly on the server console. This enables the user to control the server and communicate with other servers on the network. To start a Telnet session, the user must log in to a server by entering a valid username and password. Telnet is a common way to remotely control Web servers.
Simple Mail Transfer Protocol (SMTP) is a protocol for sending e-mail messages between servers. Most e-mail systems that send mail over the Internet use SMTP to send messages from one server to another; the messages can then be retrieved with an e-mail client using either POP or IMAP. In addition, SMTP is generally used to send messages from a mail client to a mail server. This is it is necessary to specify both the POP (or IMAP) server and the SMTP server when the e-mail application is configured.
Simple Network Management Protocol (SNMP) is a set of protocols for managing complex networks. SNMP works by sending messages, called protocol data units (PDUs), to different parts of a network. SNMP-compliant devices, called agents, store data about themselves in Management Information Bases (MIBs) and return this data to the SNMP requesters
Serial Line Internet Protocol (SLIP)is a protocol for connection to the Internet via a dial-up connection. Developed in the 1980s when modem communications typically were limited to 2400 bps, it was designed for simple communication over serial lines. SLIP can be used on RS-232 serial ports and supports asynchronous links.
A more common protocol is PPP (Point-to-Point Protocol) because it is faster and more reliable and supports functions that SLIP does not, such as error detection, dynamic assignment of IP addresses and data compression.
In general, Internet service providers offer only one protocol although some support both protocols.
Point-to-Point Protocol (PPP) is a method of connecting a computer to the Internet. PPP is more stable than the older SLIP protocol and provides error checking features. Working in the data link layer of the OSI model, PPP sends the computer's TCP/IP packets to a server that puts them onto the Internet.