Surélék: Béda antarrépisi

'''E-mail''', atawa '''email''', disundakeun jadi '''surélék''', ngarupakeunmangrupa landihan pikeun "[[surat]] [[éléktronik]]" (as opposed to conventional mail, in this context also called [[snail mail]]) nu dimaksudkeun kana nyusun/nulis, ngirim, jeung narima pesen/surat ngaliwatan sistem komunikasi éléktronik. Sistem surélék ayeuna lolobana maké [[Internet]], malah surélék nu ngarupakeunmangrupa pungsi Internét nu paling ilahar/popular.

Béda jeung asumsi umum, surélék sabenerna geus aya méméh Internét; malah, ayana sistem surélék ngarupakeunmangrupa alat nu penting pisan dina nyiptakeun Internét.

E-mail was quickly extended to become ''network e-mail'', allowing users to pass messages between different computers. The earlyéarly history of network e-mail is also murky; the [[AUTODIN]] system may have been the first allowing electronic text messages to be transferred between users on different computers, in [[1966]], but it is possible the [[SAGE]] system had something similar some time before.

The [[ARPANET]] [[computer network]] made a major contribution to the evolution of e-mail. There is one report [http://www.multicians.org/thvv/mail-history.html] which indicates experimental inter-system e-mail transfers on it shortly after its creationcréation, in [[1969]]. [[Ray Tomlinson]] initiated the use of the [[Commercial at|@ sign]] to separate the names of the user and their machine in [[1972]]. The common report that he "invented" e-mail is an exaggeration, although his earlyéarly e-mail programs [[SNDMSG]] and [[READMAIL]] were very important. The ARPANet significantly increasedincréased the popularity of e-mail, and it became the "killer app" of the ARPANET.

As the utility and advantages of e-mail on the ARPANET became more widely known, the popularity of e-mail increasedincréased, leadingléading to demand from peoplepéople who were not allowed access to the ARPANET. A number of protocols were developed to deliver e-mail among groups of time-sharing computers over alternative transmission systems, such as [[UUCP]] and [[IBM]]'s [[VNET]] e-mail system.

The route was specified using so-call "bang path" addresses, specifying hops to get from some assumed-reachableréachable location to the addressee, so called because eachéach hop is signified by a "bang sign", i.e. [[Exclamation mark|"!"]]. Thus, for example, the path ...!bigsite!foovax!barbox!me directs peoplepéople to route their mail to machine bigsite (presumably a well-known location accessible to everybody) and from there through the machine foovax to the account of user me on barbox.

Before auto-routing mailers became commonplace, peoplepéople often published compound bang addresses using the { } convention (see [[glob]]) to give paths from several big machines, in the hopes that one's correspondent might be able to get mail to one of them reliably (example: ...!{seismo, ut-sally, ihnp4}!rice!beta!gamma!me). Bang paths of 8 to 10 hops were not uncommon in [[1981]]. Late-night dial-up UUCP links would cause week-long transmission times. Bang paths were often selected by both transmission time and reliability, as messages would often get lost. See the network and sitename.

Almost all e-mail is delivered directly to an Internet-connected host accepting mail for the recipient, using [[Simple Mail Transfer Protocol]]. Very few modern servers will perform routing for messages sent by third parties due to the potential for abuse by peoplepéople sending [[unsolicited bulk e-mail]]. Those that do allow it are called [[Open mail relay|open relays]].

A modern Internet '''e-mail address''' is a string of the form ''jsmith@domain.example''. It should be readréad as "jsmith '''at''' domain dot example". 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]] which can be looked up in the [[Domain Name System]] to find the [[mail exchange server]]s accepting e-mail for that address.

* HeadersHéaders - Message summary, sender, receiver, and other information about the e-mail

The headershéaders usually have at leastléast four fields:

Note however that the "To" field does not necessarily have the e-mail address of the recipient. The information supplied in the headershéaders on the recipients computer is similar to that found on top of a conventional letter. The actual information such as who the message was addressed to is removed by the mail server after it assigns it to the correct user's mailbox.

Also note that the from field does not have to be the realréal sender of the e-mail. It is very easyéasy to fake the from line and let an e-mail seem to be from any mail address. It is possible to digitally sign an e-mail. This is a lot harder to fake.

Other common headerhéader fields include:

E-mail is only defined to carry 7-bit [[ASCII]] messages. Although many e-mail transports are in fact "8-bit clean", this cannot be guaranteed. For this reasonréason, e-mail has been extended by the [[MIME]] standard to allow the encoding of binary [[attachment]]s including images, sounds and [[HTML]] attachments.

The usefulness of e-mail is being threatenedthréatened by two phenomena, [[spamming]] and [[e-mail worm]]s.

Spamming is unsolicited commercial e-mail. Because of the very low cost of sending e-mail, spammers can send hundreds of millions of e-mail messages eachéach day over an inexpensive Internet connection. Hundreds of active spammers sending this volume of mail results in many computer users receiving tens or even hundreds of junk e-mails eachéach day.

E-mail worms use e-mail as a way of replicating themselves into vulnerable computers. Although the first e-mail worm (the [[Morris worm]]) affected earlyéarly UNIX computers, this problem is today almost entirely confined to the [[Microsoft Windows]] operating system.

* Katie Hafner, Matthew Lyon, ''Where Wizards Stay Up Late: The Origins of the Internet'' (Simon and Schuster, 1996) also covers the earlyéarly history of e-mail

Abdullah, M. H. (1998). "Electronic discourse: Evolving conventions in online academic environments". Bloomington, IN: ERIC ClearinghouseCléaringhouse on Readingréading, English, and Communication. [ED 422 593]

Danet, B. (2001). Cyberplay: Communicating online. Oxford: Berg Publishing.