What is
email?
Electronic mail, commonly known as email or e-mail, is a method of exchanging digital messages from an author to one or more recipients. Modern email operates across the Internet or other computer networks. Some early email systems required that the author and the recipient both be online at the same time, in common with instant messaging. Today's email systems are based on a store-and-forward model. Email servers accept, forward, deliver and store messages. Neither the users nor their computers are required to be online simultaneously; they need connect only briefly, typically to an email server, for as long as it takes to send or receive messages.
An email message consists of three components, the
message envelope, the message header, and the message body. The message header
contains control information, including, minimally, an originator's email
address and one or more recipient addresses. Usually descriptive information is
also added, such as a subject header field and a message submission date/time
stamp.
How does email work?
Here is the illustrated explanation
:
What is MIME?
Originally a text-only (7-bit ASCII and others)
communications medium, email was extended to carry multi-media content
attachments, a process standardized in RFC 2045 through 2049. Collectively,
these RFCs have come to be called Multipurpose Internet Mail Extensions (MIME).
Electronic mail predates the inception of the
Internet, and was in fact a crucial tool in creating it,[2] but the history of
modern, global Internet email services reaches back to the early ARPANET.
Standards for encoding email messages were proposed as early as 1973 (RFC 561).
Conversion from ARPANET to the Internet in the early 1980s produced the core of
the current services. An email sent in the early 1970s looks quite similar to a
basic text message sent on the Internet today.
Network-based email was initially exchanged on the
ARPANET in extensions to the File Transfer Protocol (FTP), but is now carried
by the Simple Mail Transfer Protocol (SMTP), first published as Internet
standard 10 (RFC 821) in 1982. In the process of transporting email messages between
systems, SMTP communicates delivery parameters using a message envelope
separate from the message (header and body) itself.
What is spamming?
Email spam, also known as junk email or unsolicited
bulk email (UBE), is a subset of electronic spam involving nearly identical
messages sent to numerous recipients by email. Definitions of spam usually
include the aspects that email is unsolicited and sent in bulk. One subset of
UBE is UCE (unsolicited commercial email). The opposite of "spam",
email which one wants, is called "ham", usually when referring to a
message's automated analysis (such as Bayesian filtering). Like other forms of
unwanted bulk messaging, it is named for Spam luncheon meat by way of a Monty
Python sketch in which Spam is depicted as ubiquitous and unavoidable.
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