Simple Mail Transfer Protocol (SMTP) is an Internet standard In computer network engineering, an Internet Standard is a normative specification of a technology or methodology applicable to the Internet. Internet Standards are created and published by the Internet Engineering Task Force (IETF) for electronic mail Electronic mail, commonly called email or e-mail, is a method of exchanging digital messages across the Internet or other computer networks. Originally, email was transmitted directly from one user to another computer. This required both computers to be online at the same time, a la instant messenger. Today's email systems are based on a store-and- (e-mail) transmission across Internet Protocol The Internet Protocol is a protocol used for communicating data across a packet-switched internetwork using the Internet Protocol Suite, also referred to as TCP/IP (IP) networks. SMTP was first defined in RFC 821 (STD In computer network engineering, an Internet Standard is a normative specification of a technology or methodology applicable to the Internet. Internet Standards are created and published by the Internet Engineering Task Force (IETF) 15) (1982)[1], and last updated by RFC 5321 (2008)[2] which includes the extended SMTP Extended SMTP , sometimes referred to as Enhanced SMTP, is a definition of protocol extensions to the Simple Mail Transfer Protocol standard. The extension format was defined in IETF publication RFC 1869 (1995) which established a general structure for all existing and future extensions (ESMTP) additions, and is the protocol in widespread use today. SMTP is specified for outgoing mail transport and uses TCP The Transmission Control Protocol is one of the core protocols of the Internet Protocol Suite. TCP is one of the two original components of the suite (the other being Internet Protocol, or IP), so the entire suite is commonly referred to as TCP/IP. Whereas IP handles lower-level transmissions from computer to computer as a message makes its way port 25.
While electronic mail servers Within Internet message handling services , a message transfer agent or mail transfer agent (MTA) or mail relay is a computer process or software agent that transfers electronic mail messages from one computer to another, in single hop application-level transactions. A MTA implements both the client (sending) and server (receiving) portions of the and other mail transfer agents Within Internet message handling services , a message transfer agent or mail transfer agent (MTA) or mail relay is a computer process or software agent that transfers electronic mail messages from one computer to another, in single hop application-level transactions. An MTA implements both the client (sending) and server (receiving) portions of use SMTP to send and receive mail messages, user-level client mail applications typically only use SMTP for sending messages to a mail server for relaying. For receiving messages, client applications usually use either the Post Office Protocol In computing, the Post Office Protocol is an application-layer Internet standard protocol used by local e-mail clients to retrieve e-mail from a remote server over a TCP/IP connection. POP and IMAP (Internet Message Access Protocol) are the two most prevalent Internet standard protocols for e-mail retrieval. Virtually all modern e-mail clients and (POP) or the Internet Message Access Protocol The Internet Message Access Protocol is one of the two most prevalent Internet standard protocols for e-mail retrieval, the other being the Post Office Protocol (POP). Virtually all modern e-mail clients and mail servers support both protocols as a means of transferring e-mail messages from a server (IMAP) or a proprietary system (such as Microsoft Exchange or Lotus Notes/Domino) to access their mail box accounts on a mail server.
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History
Various forms of one-to-one electronic messaging were used in the 1960s. People communicated with one another using systems developed for specific mainframe Mainframes are powerful computers used mainly by large organizations for critical applications, typically bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing computers. As more computers were interconnected, especially in the US Government's ARPANET ARPANET , created by a small research team at the head of the Massachusetts Institute of Technology and the Defense Advanced Research Projects Agency (DARPA) of the United States Department of Defense, was the world's first operational packet switching network, and one of the networks that came to compose the global Internet. The packet switching, standards were developed to allow users using different systems to be able to e-mail Electronic mail, commonly called email or e-mail, is a method of exchanging digital messages across the Internet or other computer networks. Originally, email was transmitted directly from one user to another computer. This required both computers to be online at the same time, a la instant messenger. Today's email systems are based on a store-and- one another. SMTP grew out of these standards developed during the 1970s.
SMTP can trace its roots to two implementations described in 1971, the Mail Box Protocol, which has been disputed to actually have been implemented,[3] but is discussed in RFC 196 and other RFCs, and the SNDMSG program, which, according to RFC 2235, Ray Tomlinson Raymond Samuel Tomlinson is a programmer who implemented an email system in 1971 on the ARPANet. Email had been previously sent on other networks such as AUTODIN. It was the first system able to send mail between users on different hosts connected to the ARPAnet (previously, mail could only be sent to others who used the same computer). To achieve of BBN BBN Technologies is a high-technology company which provides research and development services. BBN is based next to Fresh Pond in Cambridge, Massachusetts, USA. It is perhaps best known for its work in the development of packet switching (including the ARPANET and the Internet) and for its 1978 acoustical analysis for the House Select Committee "invents" for TENEX The TOPS-20 operating system by Digital Equipment Corporation was the second proprietary OS for the PDP-10 mainframe computer. TOPS-20 began in 1969 as Bolt, Beranek and Newman's TENEX operating system, using special paging hardware. The TOPS-20 system is almost entirely unrelated to the similarly-named TOPS-10, but it was shipped with the PA1050 computers the sending of mail across the ARPANET.[4][5][6] Fewer than 50 hosts were connected to the ARPANET at this time.[7]
Further implementations include FTP Mail [8] and Mail Protocol, both from 1973.[9] Development work continued throughout the 1970s, until the ARPANET converted into the modern Internet The Internet is a global system of interconnected computer networks that use the standard Internet Protocol Suite to serve billions of users worldwide. It is a network of networks that consists of millions of private, public, academic, business, and government networks of local to global scope that are linked by a broad array of electronic and around 1980. Jon Postel Jonathan Bruce Postel was an American computer scientist who made many significant contributions to the development of the Internet, particularly with respect to standards. He is known principally for being the Editor of the Request for Comment (RFC) document series, and for administering the Internet Assigned Numbers Authority until his death then proposed a Mail Transfer Protocol in 1980 that began to remove the mail's reliance on FTP File Transfer Protocol is a standard network protocol used to copy a file from one host to another over a TCP/IP-based network, such as the Internet. FTP is built on a client-server architecture and utilizes separate control and data connections between the client and server. FTP is used with user-based password authentication or with anonymous.[10] SMTP was published as RFC 821 in August 1982, also by Postel.
The SMTP standard was developed around the same time as Usenet Duke University graduate students Tom Truscott and Jim Ellis conceived the idea in 1979 and it was established in 1980. Users read and post messages to one or more categories, known as newsgroups. Usenet resembles a bulletin board system (BBS) in many respects, and is the precursor to the various Internet forums that are widely used today; and can, a one-to-many communication network with some similarities.
SMTP became widely used in the early 1980s. At the time, it was a complement to Unix to Unix Copy Program UUCP is an abbreviation for Unix-to-Unix Copy. The term generally refers to a suite of computer programs and protocols allowing remote execution of commands and transfer of files, email and netnews between computers. Specifically, UUCP is one of the programs in the suite; it provides a user interface for requesting file copy operations. The UUCP (UUCP) mail, which was better suited to handle e-mail transfers between machines that were intermittently connected. SMTP, on the other hand, works best when both the sending and receiving machines are connected to the network all the time. Both use a store and forward Store and forward is a telecommunications technique in which information is sent to an intermediate station where it is kept and sent at a later time to the final destination or to another intermediate station. The intermediate station, or node in a networking context, verifies the integrity of the message before forwarding it. In general, this mechanism and are examples of push technology Push technology, or server push, describes a style of Internet-based communication where the request for a given transaction is initiated by the publisher or central server. It is contrasted with pull technology, where the request for the transmission of information is initiated by the receiver or client. Though Usenet's newsgroups A usenet newsgroup is a repository usually within the Usenet system, for messages posted from many users in different locations. The term may be confusing to some, because it is usually a discussion group. Newsgroups are technically distinct from, but functionally similar to, discussion forums on the World Wide Web. Newsreader software is used to are still propagated with UUCP between servers,[11] UUCP mail has virtually disappeared[12] along with the "bang paths UUCP is an abbreviation for Unix-to-Unix Copy. The term generally refers to a suite of computer programs and protocols allowing remote execution of commands and transfer of files, email and netnews between computers. Specifically, UUCP is one of the programs in the suite; it provides a user interface for requesting file copy operations. The UUCP" it used as message routing headers.
The article about sender rewriting Sender Rewriting Scheme is a technique to re-mail an email message so that eventual Delivery Status Notifications can reach the original message sender. In this context, re-mailing is an alternative to Email forwarding, which is not allowed by the Sender Policy Framework contains technical background info about the early SMTP history and source routing before RFC 1123.
Sendmail Sendmail is a general purpose internetwork email routing facility that supports many kinds of mail-transfer and -delivery methods, including the Simple Mail Transfer Protocol used for email transport over the Internet was one of the first (if not the first) mail transfer agents to implement SMTP.[citation needed] Some other popular SMTP server programs include Postfix Postfix is a free and open source mail transfer agent , a computer program for the routing and delivery of email. It is intended as a fast, easy-to-administer, and secure alternative to the widely-used Sendmail MTA, qmail qmail is a mail transfer agent that runs on Unix. It was written, starting December 1995, by Daniel J. Bernstein as a more secure replacement for the popular Sendmail program. qmail's source code is in the public domain, making qmail free software, Novell GroupWise GroupWise is a messaging and collaborative software platform from Novell that supports email, calendaring, personal information management, instant messaging, and document management. The platform consists of the client software, which is available for Windows, Mac OS X, and Linux, and the server software, which is supported on Windows Server,, Exim Exim is a mail transfer agent used on Unix-like operating systems. Exim is free software distributed under the terms of the GNU General Public Licence, and it aims to be a general and flexible mailer with extensive facilities for checking incoming e-mail, Novell NetMail M+NetMail is an ISP-grade E-mail package by Messaging Architects. It is designed to deliver scalable messaging and calendaring services, using Internet-standard protocols , across a large enterprise, or to a large group of users who are not particularly associated (for example, the user population of a typical ISP). The original name for the, Microsoft Exchange Server Microsoft Exchange Server is the server side of a client-server, collaborative application product developed by Microsoft. It is part of the Microsoft Servers line of server products and is used by enterprises using Microsoft infrastructure solutions. Exchange's major features consist of electronic mail, calendaring, contacts and tasks; support, Sun Java System Messaging Server.
Message submission (RFC 2476) and SMTP-AUTH (RFC 2554) were introduced in 1998 and 1999, both describing new trends in e-mail delivery. Originally, SMTP servers were typically internal to an organization, receiving mail for the organization from the outside, and relaying messages from the organization to the outside. But as time went on, SMTP servers (Mail transfer agents), in practice, were expanding their roles to become message submission agents for Mail user agents An email client, email reader, or more formally mail user agent , is a computer program used to manage email, some of which were now relaying mail from the outside of an organization. (e.g. a company executive wishes to send e-mail while on a trip using the corporate SMTP server.) This issue, a consequence of the rapid expansion and popularity of the World Wide Web The World Wide Web, abbreviated as WWW and commonly known as the Web, is a system of interlinked hypertext documents accessed via the Internet. With a web browser, one can view web pages that may contain text, images, videos, and other multimedia and navigate between them by using hyperlinks. Using concepts from earlier hypertext systems, British, meant that the SMTP protocol had to include specific rules and methods for relaying mail and authenticating users to prevent abuses such as relaying of unsolicited e-mail (spam E-mail spam, also known as junk e-mail, is a subset of spam that involves nearly identical messages sent to numerous recipients by e-mail. A common synonym for spam is unsolicited bulk e-mail . Definitions of spam usually include the aspects that email is unsolicited and sent in bulk. "UCE" refers specifically to unsolicited commercial e-).
As this protocol started out purely ASCII The American Standard Code for Information Interchange is a character-encoding scheme based on the ordering of the English alphabet. ASCII codes represent text in computers, communications equipment, and other devices that use text. Most modern character-encoding schemes are based on ASCII, though they support many more characters than did ASCII text-based, it did not deal well with binary files. Standards such as Multipurpose Internet Mail Extensions (MIME MIME's use, however, has grown beyond describing the content of e-mail to describing content type in general, including for the web) were developed to encode binary files for transfer through SMTP. Mail transfer agents (MTAs) developed after Sendmail Sendmail is a general purpose internetwork email routing facility that supports many kinds of mail-transfer and -delivery methods, including the Simple Mail Transfer Protocol used for email transport over the Internet also tended to be implemented 8-bit-clean 8-bit clean describes a computer system that correctly handles 8-bit character sets, such as the ISO 8859 series and the UTF-8 encoding of Unicode, so that the alternate "just send eight" strategy could be used to transmit arbitrary text data (in any 8-bit ASCII-like character encoding) via SMTP. 8-bit-clean MTAs today tend to support the 8BITMIME Extended SMTP , sometimes referred to as Enhanced SMTP, is a definition of protocol extensions to the Simple Mail Transfer Protocol standard. The extension format was defined in IETF publication RFC 1869 (1995) which established a general structure for all existing and future extensions extension, permitting binary files to be transmitted almost as easily as plain text.
Many people contributed to the core SMTP specifications, among them Jon Postel Jonathan Bruce Postel was an American computer scientist who made many significant contributions to the development of the Internet, particularly with respect to standards. He is known principally for being the Editor of the Request for Comment (RFC) document series, and for administering the Internet Assigned Numbers Authority until his death, Eric Allman Eric Paul Allman is an American computer programmer who developed sendmail and its precursor delivermail in the late 1970s and early 1980s at UC Berkeley, Dave Crocker, Ned Freed Edwin Earl "Ned" Freed was born in 1959 in Oklahoma City, Oklahoma. He graduated from Groton School in 1978. He was awarded a Bachelor of Science degree in Engineering from Harvey Mudd College in 1982, Randall Gellens, John Klensin His career includes 30 years as a Principal Research Scientist at MIT, a stint as INFOODS Project Coordinator for the United Nations University, Distinguished Engineering Fellow at MCI WorldCom, and Internet Architecture Vice President at AT&T; he is now an independent consultant, and Keith Moore He was born in Nashville, Tennessee, United States of America. He earned a Bachelor of Science degree in Electrical Engineering from Tennessee Technological University in 1985, and a Master of Science degree in Computer Science from the University of Tennessee in 1996.
Mail processing model
The overall flow for message creation, mail transport and delivery may be illustrated as follows:
- sending MUA → MSA → sending MTA → receiving MTA → MDA → Mailstore for retrieval by MUA
E-mail is submitted from a mail client (MUA, message user agent) to a mail server (MSA, message submission agent) using SMTP usually. From there, the MSA delivers the mail to an MTA, often running on the same machine. A message may be directly submitted to an MTA: TCP The Transmission Control Protocol is one of the core protocols of the Internet Protocol Suite. TCP is one of the two original components of the suite (the other being Internet Protocol, or IP), so the entire suite is commonly referred to as TCP/IP. Whereas IP handles lower-level transmissions from computer to computer as a message makes its way port 587 is typically used for submission to MSAs (thence to MTAs), while TCP port 25 must be used for transferring to MTAs.
The MTA looks up the destination's mail exchanger record A mail exchanger record is a type of resource record in the Domain Name System that specifies a mail server responsible for accepting email messages on behalf of a recipient's domain and a preference value used to prioritize mail delivery if multiple mail servers are available. The set of MX records of a domain name specifies how email should be (MX record) in the Domain name system The Domain Name System is a hierarchical naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participants. Most importantly, it translates domain names meaningful to humans into the numerical (binary) identifiers (DNS), and relays the mail to a server on record for that domain via TCP port 25 and SMTP. (The article on MX record discusses many factors in determining which server the sending MTA connects to.) Once the receiving MTA accepts the incoming message, it is delivered via a mail delivery agent A mail delivery agent or message delivery agent is computer software that transfers the responsibility for the management of e-mail messages from the message transfer agent (MTA) within the message handling service (MHS) to a recipient's environment, commonly transferring them into a mailbox (MDA) to a server which is designated for local mail delivery. The MDA either delivers the mail directly to storage, or forwards it over a network using either SMTP or the Local Mail Transfer Protocol (LMTP), a derivative of ESMTP designed for this purpose. Once delivered to the local mail server, the mail is stored for batch retrieval by authenticated mail clients (MUAs). Mail is retrieved by end-user applications, called email clients, using Internet Message Access Protocol (IMAP), a protocol that both facilitates access to mail and manages stored mail, or the Post Office Protocol (POP) which typically uses the traditional mbox mail file format or a proprietary system such as Microsoft Exchange/Outlook or Lotus Notes/Domino. Webmail clients may use either method, but the retrieval protocol is often not a formal standard. Some local mail servers and MUAs are capable of either push or pull mail retrieval.
SMTP defines message transport, not the message content. Thus, it defines the mail envelope and its parameters, such as the envelope sender, but not the header or the body of the message itself. STD 10 and RFC 5321 define SMTP (the envelope), while STD 11 and RFC 5322 define the message (header and body), formally referred to as the Internet Message Format.
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TECH.BLORGE.com
FileZilla: FileZilla is an extremely easy FTP (File Transfer Protocol ) client for working with files on your Web server. There is a slight bit of a learning ...
RichC
Wed, 26 May 2010 20:02:58 GM
SMTP stands for . Simple Mail Transfer Protocol. . SMTP is an Internet standard used to transmit email messages between two servers across different IP (Internet Protocol) networks. It is a text-based protocol in which the text message is ...
Q. a. Simple Mail Transfer Protocol (SMTP) transfers e-mail. b. Hypertext Transfer Protocol (HTTP) transfers displayable Web pages and related files. c. FTP is an application protocol that uses the Internet's HTTP protocols. d. Transmission Control Protocol (TCP) puts packets transmitted across the Internet or a network back together. e. Internet Protocol just delivers packets of information across the Internet or a network
Asked by zaaaaaa - Tue Sep 22 20:03:38 2009 - - 1 Answers - 0 Comments
A. ftp is file transfer protocol..it doesnt have to use http
Answered by minus 10 - Tue Sep 22 20:15:22 2009
