The Email Operation Overview Computer Science Essay

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Electronic mail, most commonly abbreviated email and e-mail, is a method of exchanging digital messages. E-mail systems are based on a store-and-forward model in which e-mail computer server systems accept, forward, deliver and store messages on behalf of users, who only need to connect to the e-mail infrastructure, typically an e-mail server, with a network-enabled deice for the duration of message submission or retrieval. Originally, e-mail was always transmitted directly from one user's device to another's; nowadays this is rarely the case.


There are several spelling variations that are occasionally the cause of vehement disagreement.

email is the form officially required by IETF Request for Comments and working groups and is also recognized in most dictionaries.

E-mail is a form still recommended by some prominent journalistic and technical style guides.

Mail was the form used in the original RFC. The service is referred to as mail and a single piece of electronic mail is called a message.

eMail, capitalizing only the letter M, was common among ARPANET users and early developers from Unix, CMS, AppleLink, eWorld, AOL, Genie, and Hotmail.

EMail is a traditional form that has been used in RFCs for the "Author's Address", and is expressly required "…for historical reasons…"

Operation Overview

There is a typical sequence of events that takes place when Alice composes a message using her mail user agent (MUA). She enters the e-mail address of her correspondent, and hits the "send" button.

Here MUA formats the message in e-mail format and uses the Simple Mail Transfer Protocol (SMTP) to send the message to the local mail transfer agent (MTA), in this case, run by Alice's Internet Service Provider (ISP).

The MTA looks at the destination address provided in the SMTP protocol (not from the message header), in this case An Internet e-mail address is a string of the form localpart@exampledomain. The part before the @ sign is the local part of the address, often the username of the recipient, and the part after the @ sign is a domain name or a fully qualified domain name. The MTA resolves a domain name to determine the fully qualified domain name of the mail exchange server in the Domain Name System (DNS).

The DNS server for the domain,, responds with any MX records listing the mail exchange servers for that domain, in this case, a server run by Bob's ISP. sends the message to using SMTP, which delivers it to the mailbox of the user bob.

Bob presses the "get mail" button in his MUA, which picks up the message using the Post Office Protocol (POP3).

That sequence of events applies to the majority of e-mail users. However, there are many alternative possibilities and complications to the e-mail system:

•Alice or Bob may use a client connected to a corporate e-mail system, such as IBM Lotus Notes or Microsoft Exchange. These systems often have their own internal e-mail format and their clients typically communicate with the e-mail server using a vendor-specific, proprietary protocol. The server sends or receives e-mail via the Internet through the product's Internet mail getaway which also does any necessary reformatting. If Alice and Bob work for the same company, the entire transaction may happen completely within a single corporate e-mail system.

•Alice may not have a MUA on her computer but instead may connect to a webmail service.

•Alice's computer may run its own MTA, so avoiding the transfer at step 1.

•Bob may pick up his e-mail in many ways, for example using the Internet Message Access Protocol, by logging into and reading it directly, or by using a webmail service.

•Domains usually have several mail exchange servers so that they can continue to accept mail when the main mail exchange server is not available.

•E-mail messages are not secure if e-mail encryption is not used correctly.

Many MTAs used to accept messages for any recipient on the Internet and do their best to deliver them. Such MTAs are called open mail relays. This was very important in the early days of the Internet when network connections were unreliable. If an MTA couldn't reach the destination, it could at least deliver it to a relay closer to the destination. The relay stood a better chance of delivering the message at a later time. However, this mechanism proved to be exploitable by people sending unsolicited bulk e-mail and as a consequence very few modern MTAs are open mail relays, and many MTAs don't accept messages from open mail relays because such messages are very likely to be spam.


In Society

There are numerous ways in which people have changed the way they communicate in the last 50 years; email is certainly one of them. Traditionally, social interaction in the local community was the basis for communication-face to face. Yet, today face-to-face meetings are no longer the primary way to communicate as one can use a landline telephone, mobile phones, fax services, or any number of the computer mediated communications such as e-mail.


Flaming occurs when a person sends a message with angry or antagonistic content. Flaming is assumed to be more common today because of the ease and impersonality of e-mail communications: confrontations in person or via telephone require direct interaction, where social norms encourage civility, whereas typing a message to another person is an indirect interaction, so civility may be forgotten. Flaming is generally looked down upon by Internet communities as it is considered rude and non-productive.

E-Mail Bankruptcy

Also known as "e-mail fatigue", e-mail bankruptcy is when a user ignores a large number of e-mail messages after falling behind in reading and answering them. The reason for falling behind is often due to information overload and a general sense there is so much information that it is not possible to read it all. As a solution, people occasionally send a boilerplate message explaining that the e-mail inbox is being cleared out.

In Business

E-mail was widely accepted by the business community as the first broad electronic communication medium and was the first 'e-revolution' in business communication. E-mail is very simple to understand and like postal mail, e-mail solves two basic problems of communication: logistics and synchronization (see below).

LAN based email is also an emerging form of usage for business. It not only allows the business user to download mail when offline, it also provides the small business user to have multiple users e-mail ID's with just one e-mail connection.


•The problem of logistics

Much of the business world relies upon communications between people who are not physically in the same building, area or even country; setting up and attending an in-person meeting, telephone call, or conference call can be inconvenient, time-consuming, and costly. E-mail provides a way to exchange information between two or more people with no set-up costs and that is genrally far less expensive than physical meetings or phone calls.

•The problem of synchronization

With real time communication by meetings or phone calls, participants have to work on the same schedule, and each participant must spend the same amount or time in the meeting or call. E-mail allows asynchrony; each participant may control their schedule independently.


Most business workers today spend from one to two hours of their working day on e-mail; reading, ordering, sorting, 're-contextualizing' fragmented information, and writing e-mail. The use of e-mail is increasing due to increasing levels of globalization-labor division and outsourcing amongst other things. E-mail can lead to some well-known problems.

•Loss of Context: which means that the context is lost forever; there is no way to get the text back. Information in context (as in a newspaper) is much easier and faster to understand than unedited and sometimes unrelated fragments of information. Communicating in context can only be achieved when both parties have a full understanding of the context and issue in question.

•Information overload: E-mail is a push technology-the sender controls who receives the information. Convenient availability of mailing lists and use of "copy all" can lead to people receiving unwanted or irrelevant information of no use to them.

•Inconsistency: E-mail can duplicate information. This can be a problem when a large team is working on documents and information while not in constant contact with the other members of their team.

Despite these disadvantages, e-mail has become the most widely used medium of communication within the business world.


Information Overload

A December 2007 New York Times blog post described E-mail as "a $650 Billion Drag on the Economy", and the New York Times reported in April 2008 that "E-MAIL has become the bane of some people's professional lives" due to information overload, yet "none of the current wave of high-profile Internet start-ups focused on e-mail really eliminates the problem of e-mail overload because none helps us prepare replies".

Technology investors reflect similar concerns.

Spamming and Computer Viruses

The usefulness of e-mail is being threatened by four phenomena: e-mail bombardment, spamming, phishing, and e-mail worms.

Spamming is unsolicited commercial (or bulk) e-mail. Because of the very low cost of sending e-mail, spammers can send hundreds of millions of e-mail messages each day over an inexpensive Internet connection. Hundreds of active spammers sending this volume of mail results in information overload for many computer users who receive voluminous unsolicited e-mail each day.

E-mail worms use e-mail as a way of replicating themselves into vulnerable computers. Although the first e-mail worm affected UNIX computers, the problem is most common today on the more popular Microsoft Windows operating system.

The combination of spam and worm programs results in users receiving a constant drizzle of junk e-mail, which reduces the usefulness of e-mail as a practical tool.

A number of anti-spam techniques mitigate the impact of spam. In the United States, U.S. Congress has also passed a law, the Can Spam Act of 2003, attempting to regulate such e-mail. Australia also has very strict spam laws restricting the sending of spam from an Australian ISP, but its impact has been minimal since most spam comes from regimes that seem reluctant to regulate the sending of spam.

E-Mail Spoofing

E-mail spoofing occurs when the header information of an email is altered to make the message appear to come from a known or trusted source. It is often used as a ruse to collect personal information.

E-Mail Bombing

E-mail bombing is the intentional sending of large volumes of messages to a target address. The overloading of the target email address can render it unusable and can even cause the mail server to crash.

Privacy Concerns

E-mail privacy, without some security precautions, can be compromised because:

e-mail messages are generally not encrypted

e-mail messages have to go through intermediate computers before reaching their destination, meaning it is relatively easy for others to intercept and read messages

many Internet Service Providers (ISP) store copies of e-mail messages on their mail servers before they are delivered. The backups of these can remain for up to several months on their server, despite deletion from the mailbox.

the "Received:"-fields and other information in the e-mail can often identify the sender, preventing anonymous communication.

There are cryptography applications that can serve as a remedy to one or more of the above. For example, Virtual Private Networks or the Tor anonymity network can be used to encrypt traffic from the user machine to a safer network while GPG, PGP, SMEmail [42] , or S/MIME can be used for end-to-end message encryption, and SMTP STARTTLS or SMTP over Transport Layer Security/Secure Sockets Layer can be used to encrypt communications for a single mail hop between the SMTP client and the SMTP server.

Additionally, many mail user agents do not protect logins and passwords, making them easy to intercept by an attacker. Encrypted authentication schemes such as SASL prevent this.

Finally, attached files share many of the same hazards as those found in peer-to-peer filesharing. Attached files may contain trojans or viruses.

Tracking of Sent Mail

The original SMTP mail service provides limited mechanisms for tracking a transmitted message, and none for verifying that it has been delivered or read. It requires that each mail server must either deliver it onward or return a failure notice (bounce message), but both software bugs and system failures can cause messages to be lost. To remedy this, the IETF introduced Delivery Status Notifications (delivery receipts) and Message Disposition Notifications (return receipts); however, these are not universally deployed in production.

US Government

The US Government has been involved in e-mail in several different ways Starting in 1977, the US Postal Service (USPS) recognized that electronic mail and electronic transactions posed a significant threat to First Class mail volumes and revenue. Therefore, the USPS initiated an experimental e-mail service known as E-COM. Electronic messages were transmitted to a post office, printed out, and delivered as hard copy. To take advantage of the service, an individual had to transmit at least 200 messages. The delivery time of the messages was the same as First Class mail and cost 26 cents. Both the Postal Regulatory Commission and the Federal Communications Commission opposed E-COM. The FCC concluded that E-COM constituted common carriage under its jurisdiction and the USPS would have to file a tariff. Three years after initiating the service, USPS canceled E-COM and attempted to sell it off.

The early ARPANET dealt with multiple e-mail clients that had various, and at times incompatible, formats. For example, in the system Multics, the "@" sign meant "kill line" and anything after the "@" sign was ignored The Department of Defense DARPA desired to have uniformity and interoperability for e-mail and therefore funded efforts to drive towards unified interoperable standards. This led to David Crocker, John Vittal, Kenneth Pogran, and Austin Henderson publishing RFC 733, "Standard for the Format of ARPA Network Text Message" (November 21, 1977), which was apparently not effective. In 1979, a meeting was held at BBN to resolve incompatibility issues. Jon Postel recounted the meeting in RFC 808, "Summary of Computer Mail Services Meeting Held at BBN on 10 January 1979" (March 1, 1982), which includes an appendix listing the varying e-mail systems at the time. This, in turn, lead to the release of David Crocker's RFC 822, "Standard for the Format of ARPA Internet Text Messages" (August 13, 1982).

The National Science Foundation took over operations of the ARPANET and Internet from the Department of Defense, and initiated NSFNet, a new backbone for the network. A part of the NSFNet AUP forbade commercial traffic. In 1988, Vint Cerf arranged for an interconnection of MCI Mail with NSFNET on an experimental basis. The following year Compuserve e-mail interconnected with NSFNET. Within a few years the commercial traffic restriction was removed from NSFNETs AUP, and NSFNET was privatized.

In the late 1990s, the Federal Trade Commission grew concerned with fraud transpiring in e-mail, and initiated a series of procedures on spam, fraud, and phishing. In 2004, FTC jurisdiction over spam was codified into law in the form of the CAN SPAM Act. Several other US Federal Agencies have also exercised jurisdiction including the Department of Justice and the Secret Service.

See Also


E-mail encryption

Google Wave

HTML e-mail

Internet fax

L- or letter mail, e-mail letter and letter e-mail

Mule (e-mail)

Privacy-enhanced Electronic Mail

Push e-mail


An electronic mail message consists of two components, the message header, and the message body, which is the email's content. The message header contains control information, including, minimally, an originator's email address and one or more recipient addresses. Usually additional information is added, such as a subject header field. Originally a text-only communications medium, email was extended to carry multi-media content attachments, which were standardized in with RFC 2045 through RFC 2049, collectively called, Multipurpose Internet Mail Extensions (MIME). The foundation for today's global Internet e-mail service was created in the early ARPANET and standards for encoding of messages were proposed as early as 1973 (RFC 561). An e-mail sent in the early 1970s looked very similar to one sent on the Internet today. Conversion from the ARPANET to the Internet in the early 1980s produced the core of the current service. Network-based email was initially exchanged on the ARPANET in extensions to the File Transfer Protocol (FTP), but is today carried by the Simple Mail Transfer Protocol (SMTP), first published as Internet standard 10 (RFC 821) in 1982. In the process of transporting e-mail messages between systems, SMTP communicates delivery parameters using a message envelope separately from the message (header and body) itself.