Electronic mail. !! Task - Assignment!!

Transcription

1 **** 1 Electronic mail ***-!! Task - Assignment!! 2 You can learn about online through the Internet from

2 **** summary 3 The following gives an overview of electronic mail: What it is Using through the WWW Using with a dedicated client software **** prerequisites 4 Before using , you should ideally have some knowledge and skills related to computer hardware computer software the Internet the WWW

3 **** general description 5 Electronic mail allows network users to send messages to each other by computer. The process is like the postal system in some ways, but in the case of electronic mail, the mail agent is a computer program»the address for sending is the address of an electronic mailbox»the message is given to the mail system electronically, not on paper»the transport system is the data communication network **** using central, isolated systems 6 Send computer Read 1 A 2 B

4 ?? Question?? 7 Which problems would be be associated with the use of of simple, isolated, CENTRAL systems and services for ? using central, isolated systems: problems 8 In the case of isolated, central systems, there would be problems:»message senders must have accounts with various services to address various persons, and analogously, persons who want to receive messages must have accounts with various services used by the various senders.»as one of the consequences, each user should connect with various systems to check if has arrived in their various mailboxes.

5 gateways link various systems 9 Gateways solve the problems associated with isolated systems by linking these with each other. **** using linked systems 10 computer I computer II II Send Read 1 A 2 B

6 ****Examples examples of global systems 11 Systems with 1 computer systems»compuserve (in US)»Hotmail (in US)»Yahoo Mail Global, linked network systems»uucp network»fidonet...»x-400 network»internet SMTP **** getting started 12 To start, you need: a networked computer a mail system (software) a personal mailbox for you a little know-how addresses, if you want to send messages...

7 in the Internet 13 One of the most interesting features of the Internet is that virtually every personal computer, minicomputer and mainframe can connect to it in one fashion or another. There are many operating systems in use on the Internet. Nearly every operating system has its own style. To overcome the mess of competing standards, the Internet has adopted a particular format for . Based on the RFC (Request for Comments) 822, it is called RFC 822-compliant . transfer protocols in the Internet 14 Sending server computer used by Y SMTP Receiving server computer A used by X Receiving server computer B used by X SMTP Receiving messages, using POP or IMAP Some sending server computer used by X SMTP Client microcomputer used by X (with client software = user agent)

8 transfer protocols in the Internet: examples 15 SMTP = Simple Mail Transfer Protocol = communications protocol used most commonly over TCP/IP links in UNIX environments for transport between mail server computers POP = Post Office Protocol IMAP = Internet Message Access Protocol is more powerful than POP; for instance it allows transfer of message headers separately *--- using a non-internet computer 16 Through public access gateways (not free of charge)»data-star in Switzerland»CompuServe in the U.S.A.»...

9 *--- the UUCP network 17 The UUCP network is a collection of computers running UNIX or UUCP-compatible systems (many PCs and BBS systems have done this). A store-and-forward network: Earlier, it was necessary to know virtually the entire network path a piece of would take in order to route it. Lately, however, UUCP network administrators have been encouraging the adaptation of Internet-style addressing. the Matrix 18 The Matrix = all the computers worldwide that can exchange at least electronic mail = Internet (+ Bitnet + UUCP + FidoNet + centralized services)

10 **** benefits 19 Overcomes time zone problems inherent to telephone Faster than classical mail International Inexpensive (free of charge in academic institutions) Data are kept in computer readable form Send to more than 1 address in 1 action Easy to include received message in the reply Allows discussion forums & journals based on problems (Part 1) 20 How to know the required address? Does your contact person have an address? The time period between sending and arriving of a message is not always known accurately and may be long. How to communicate with users on other systems/networks? (using gateways) You have to learn to use at least 1 software/system. Differences in user interface among various systems Disk capacity required to store incoming mail

11 problems (Part 2) 21 The user needs access to a computer Software required to read, store and retrieve the incoming and outgoing messages The user needs some basic understanding of computers and data communication The user may suffer from a lack of time»to read and manage the incoming information»to answer messages and queries from persons communicating by too much! 22

12 23 structure of messages Every message in most systems is composed of two basic pieces: The header This contains a series of informative lines which tell the mailing system where to deliver the mail and which provide basic memorandum-like information for the sender and recipient(s). The body This generally consists of free-form text. Example 24 in the Internet: the header Example: Date: Friday, 26 March 1993; 22:18:45 EST To: atropos@netlab.cis.brown.edu (David B. O Donnell), EL406006@brownvm.brown.edu From: dr_babe@ds9.starfleet.net (Dr. Julian Bashir) Subject: Failed mail to user foo@bar.com? Cc: postmaster@bar.com

13 in the Internet: the body 25 The body of is separated from the header by exactly one blank line. The RFC 822 specification does not state what format the body information must appear in, but the vast majority of on the Internet today consists of eighty-characterwide lines of ASCII text. some ways to communicate with the networks (Part 1) 26 NOT connected to a server in a LAN which runs software to receive and send , but accessing a gateway computer which acts as a mail server (for instance Data-Star in Switzerland, Compuserve in the USA)

14 using a bulletin board gateway computer 27 computer You The rest of the world some ways to communicate with the networks (Part 2) 28 Connected directly to a network server computer for a LAN, running the Internet SMTP software and/or the BITNET software to send and receive »using a simple character based terminal OR»using a more expensive graphics terminal

15 from a terminal connected to a mail server 29 Terminal (character-based or graphics) no software Serial line Server mail editing + mail sending software Inside Outside Internet Edit and send on server some ways to communicate with the networks (Part 3) 30 Connected directly to a network server computer for a LAN, running the Internet SMTP software and/or the BITNET software to send and receive using a work station with the same operating system as the server

16 from a workstation connected to a mail server 31 Work station Server mail editing + mail sending software Inside Outside Internet some ways to communicate with the networks (Part 4) 32 Connected directly to a network server computer for a LAN, running the Internet SMTP software and/or the BITNET software to send and receive Using a PC with DOS and a serial line connection with the server computer: using only the editing and mail software on the server, and no program(s) on your microcomputer

17 from a microcomputer, via serial line, using only the server 33 Microcomputer with DOS Serial line communications software Serial line Server mail editing + mail sending software Inside Outside Internet Edit and send using the server only some ways to communicate with the networks (Part 5) 34 Connected directly to a network server computer for a LAN, running the Internet SMTP software and/or the BITNET software to send and receive Using a PC with DOS and a serial connection with the server computer: using PC editing DOS software to edit your messages, using a DOS serial communications program to send these messages to the server, and using the mail software on the server computer

18 from a DOS microcomputer, via serial line using PC program(s) 35 Microcomputer with DOS Text editing software + serial line communications software for DOS Serial line Server mail server software Inside Outside Internet Edit on PC and send message to server; send mail using software on the server some ways to communicate with the networks (Part 6) 36 Connected directly to a network server computer: Using a microcomputer in a copy & paste computing environment (e.g. Macintosh, PC with Windows,...) and a serial line connection with the server computer:»using editing software on the microcomputer, using serial communications software to send the message to the server, with copy & paste using the server to send the message

19 from a microcomputer using copy & paste, via a serial line 37 Microcomputer with copy & paste environment Text editing software + Serial line communications software Serial line Server mail server software Inside Edit and send message to server, using copy and paste, and using the mail software on the server Outside Internet some ways to communicate with the networks (Part 7) 38 Connected directly to a network server computer for a LAN, running the Internet SMTP software and/or the BITNET software to send and receive Using a PC with network adapter with network software without mail module, and using only the mail software on the server computer, OR with network software without software, and using a separate client program on the PC, OR with network software which includes a mail module

20 from a microcomputer via a network card / adapter (1) 39 Microcomputer with DOS Network communications software for DOS without mail module Network cable Server mail editing + mail server software Edit and send message using the server Inside Outside Internet from a microcomputer via a network card / adapter (2) 40 Microcomputer with DOS Network communications software for DOS, without mail module, using separate mail client program Network cable Server mail editing + mail server software Inside Edit and send message using the client mail program Outside Internet

21 from a microcomputer via a network card / adapter (3) 41 Microcomputer with DOS Network communications software for DOS including a mail module Network cable Server mail server software Inside Outside Internet Edit and send message, using the client mail module on the microcomputer + the server mail program on the server **** addresses of persons (Internet style) 42 An electronic mail address is the string of characters that you must give an electronic mail program to direct a message to a particular person: username@computer-address Examples:»(Bitnet: user@indycms.bitnet)»internet U.S.A.: dnoonan@alex.stkate.edu»internet not-u.s.a.: pnieuwen@uia.ac.be

22 ****?? Question?? 43 What is is your full personal Internet mail address? how to find addresses of users? 44 With so many computer systems and users in the world, it is impossible to keep a complete white pages of the Internet. The problem is compounded because people come and go from the net all the time. Storing and updating that much information would be an impossible, daunting task. Nevertheless, several address directory services can be found by browsing in the WWW. Internet indexes in WWW can also be used to find an address.

23 **** reading and managing messages 45 On-line = Linked to the server computer even when reading and managing messages; for instance: using telnet to login to an computer using WWW to login to an computer Off-line! = On-line only to download messages from the server, and reading and managing messages, NOT linked to the server computer anymore! client programs for Unix 46 From a terminal or from a microcomputer emulating a terminal (using for instance telnet), using the software on the Unix-based server:»(line-oriented: mail, mailx,...)»screen-oriented: elm, pine,...

24 *---Example client program for Unix: Pine 47 Was developed by the University of Washington Office of Computing and Communications. Is freely available on the Internet via anonymous FTP. Is designed for ease-of-use with the novice computer user in mind. Is based on Internet mail protocols (e.g. SMTP). Was originally based on Elm, but has evolved much since. *---Example client program for Unix: Pine: features 48 Shows a message summary which includes the status, sender, size, date and subject of messages. Can view and process mail with the following commands: forward, reply, save, export, print, delete, capture address and search. Offers on-line help specific to each screen and context. Is very portable and runs on a variety of UNIX machines (including DECstation, NeXT, VAX and Sun).

25 *---Example client program for Unix: Pine: ease of use 49 The guiding principles for achieving ease-of-use in Pine were:»careful limitation of features»one-character mnemonic commands»always-present command menus»immediate user feedback»high tolerance for user mistakes It is intended that Pine can be learned by exploration rather than reading manuals. *--- Pico: message composition editor for Unix 50 Pico is a message composition editor running on Unix systems, which can be used for instance with the programs for Unix elm and pine. It is a very simple and easy to use text editor with text justification and a spelling checker. You can choose pico instead of another editor: for instance in elm options at V.U.B., choose as standard editor /usr/local/bin/pico -t

26 **** through the WWW: international systems 51 Some international systems based on the WWW allow you to send and read/receive messages. Examples: Hotmail of Microsoft, Yahoo! Mail, Gmail of Google Some of these systems allow you to receive/read the messages from the POP mail account provided by your ISP. Example: Yahoo! Mail **** through the WWW: local systems 52 In many institutes, local systems restricted to users of the institute, offer services related to based on the at the universities in Brussels:

27 ***-?? Question?? 53 What may be be advantages and disadvantages of of using a client for on on the WWW and not on on your personal microcomputer? **** through the WWW: advantages 54 Available from any WWW browser, and thus suitable when traveling. Client software dedicated to on your microcomputer is not required. Your address on a public system may be more stable, may last longer, than an l address provided to you by the institute where you study or work.

28 **** through the WWW: disadvantages (Part 1) 55 Uses the network inefficiently, when the sender and the receiver are close to each other, but far away from the computer. Disk space to receive and manage messages in the international systems free of charge is in most cases more limited than in other systems. Less reliable than good local systems. **** through the WWW: disadvantages (Part 2) 56 Works slower in most cases than using directly an client on your microcomputer. Some systems do not allow»filtering messages»receiving file attachments»sending file attachments or sending LARGE attached files (Not well integrated with mailto: hyperlinks.) (Advertisements can distract users.)

29 **** client programs for an Internet microcomputer 57 From a microcomputer with a network card, you can use a client program which sucks / downloads the messages from the local area network server. Most of these programs are easier to use than characterbased programs for Unix. *---Examples client programs for an Internet PC with DOS 58 For DOS, without use of Microsoft Windows: qvtnet NUPOP Pine for DOS...

30 Examples client programs for an Internet PC with Windows 59 Agent, by Forte! (added to one of the best Usenet client programs) Eudora!! (only for ) Outlook Express, and Outlook, by Microsoft!!! (for and Usenet text messages) Pegagus mail! (only for ) ****Examples + WWW client programs for an Internet PC with Windows 60 Netscape (combined with a good WWW browser and a simple Usenet client)

31 Example PC Eudora for Windows: positive properties (Part 1) 61 Allows sending and receiving binary, non-ascii files, named attachments which are automatically encoded and sent, and decoded when received. Can be used also off-line to read, manage and compose messages. Example PC Eudora for Windows: positive properties (Part 2) 62 Eudora for Macintosh is also available, with a similar user interface; that offers several advantages:»makes support by the network managers simple in a heterogeneous (PC + Macintosh + Unix) environment»allows PC and Macintosh users to discuss the common features and problems to communicate using the advanced features (such as exchange of attachments of ASCII and non-ascii files as attachments to messages)

32 Example PC Eudora for Windows: screen capture 63 ****?? Question?? 64 Which method for do do you or or will you use?

33 ****!! Task - Assignment - Exercise!! 65 Read your incoming mail. Send a simple ASCII message (for instance to to yourself).!! Task - Assignment - Exercise!! 66 Send an an message to to more than 1 person at at the same time, in in 1 action.

34 !! Task - Assignment - Exercise!! 67 Create, save and test a network signature for your own messages.!! Task - Assignment - Exercise!! 68 Forward an an message to to a third person.

35 ?? Question?? 69 What is is the difference between a carbon copy and a blind carbon copy??? Question?? 70 What is is the difference between cc cc and bcc in in ? In In which case would you use bcc?

36 reading and managing messages off-line 71 Off-line = using only a microcomputer, NOT on-line linked to the server, after downloading messages from the server to read and manage those messages, using one of the following types of programs a dedicated off-line mail reading program»a more general program, for instance a program for text editing /word processing»an client program which can be used on-line connected to the server, as well as off-line (e.g. Eudora) ***-?? Question?? 72 Can you send and receive other information types than simple text and numbers by by electronic mail?

37 ***- more than ASCII text and numbers 73 Transmission of data other than ASCII texts is possible by encoding a non-ascii file to ASCII, enclosing it in the message, and decoding the file to the original non-ascii file at the receiving end. non-ascii files encoding / decoding 74 This works manually or automatically:»manually: sender encodes to ASCII + receiver decodes»automatically / transparently for the user, in some advanced systems (for instance Eudora) Coding schemes used:»uuencode / UUdecode.UUE-files»BinHex.HQX-files»MIMEQP = MIME Quoted-Printable»...

38 MIME = Multipurpose Internet Mail Extensions 75 MIME builds on the older standard by standardizing additional fields for mail message headers that describe new types of content and organization for messages. aims of MIME 76 MIME allows mail messages to contain:»multiple objects in a single message»text having unlimited line length or overall length»character sets other than ASCII»multi-font messages»binary or application specific files»images, audio, video and multi-media messages

39 MIME: compatibility with older standards 77 MIME is designed to be compatible with older Internet mail standards. In particular, it is compatible with RFC 822: If a mail reading program receives a message that is a MIME message then it will likely perform additional processing for the MIME message that it would not perform for non-mime messages. MIME: how it works 78 In order to allow mail reading programs to recognize MIME messages, MIME messages are required to contain a MIME-Version header field. The MIME-Version header field specifies the version of the MIME standard that the message conforms to.

40 *--- the MIME Quoted-Printable message encoding scheme 79 Most appropriate for data that consist primarily of printable ASCII characters. Printable ASCII character are represented as themselves. The equals sign (=) serves as an escape character: Any character that is not a printable or white space ASCII character is represented as =, followed by two hexadecimal digits. (An = in the message is also represented in this way.) Lines that are longer than 76 characters are cut off after the 75th character and the line ends with an equals sign. *--- MIME Quoted-Printable: advantages 80 Only few additional characters are required. In other words, encoding does not make the message much bigger. The message can be read by people who do not have a MIME aware mail reading program.

41 ***-?? Question?? 81 Which kind of of files can be be sent as as attachments? ****!! Task - Assignment - Exercise!! 82 Send a simple text message to to yourself, receive it, it, and read it. it. Send a non-text file to to yourself, by by , receive it, it, and view or or execute it it (for instance a word processing file).

42 file attachments: a few practical tips 83 Files take normally longer to send and download than messages. So send files only when necessary. If the file is large, use a utility before sending to compress the file (for instance by zipping the file). If you want to send more than 1 file that should be kept together, the consider not sending multiple attached files, but compressing them all into 1 using some utility program. ***-!! Task - Assignment!! 84 Read Brain, Marshall How works. [online] Available from:

43 organisation of your mailboxes 85 Incoming and outgoing messages can be stored in an In and Out mail box. More mailboxes can be created however. Thus software can help you managing your work. Examples of useful additional boxes:»to do (normal)»to do (only when Internet can be accessed)»to follow up»a mailbox for each of your subjects / activities / interests?? Question?? 86 How have you organised your boxes?

44 ?? Question?? 87 Compare the communication media fax and electronic mail. versus fax: types of data/information transmitted 88 Fax Black and white images ASCII (unformatted text + numbers + Postscript documents) + data encoded to ASCII (formatted text, programs, sound, images, video, multimedia,...)

45 versus fax: requirements 89 Hardware + software required Communications network Fax Fax machine or fax card + fax software (+ scanner) Telephone network Computer + software Data communications network or telephone network versus fax: further comparison 90 Property Time between sending and receiving Suitability of received data for manipulation on computer Costs Fax Immediately Can be immediately

46 for access to information resources 91 electronic mailing lists (unmoderated or moderated) electronic newsletters and journals (those which are distributed by ) current awareness services other computer network based information sources which can better be accessed with other, more interactive methods: for instance: computer archives accessible with anonymous ftp Netiquette = network etiquette: some of the important rules (Part 1) 92 Cover only one subject per message. Include a meaningful subject description in your message. Do not type messages in all caps. When summarizing, summarize. Be brief. In the case of a question: begin the subject line with a?

47 Netiquette = network etiquette: some of the important rules (Part 2) 93 Beware of making strong, emotional, angry or sarcastic statements. When responding to a message,»either attach the original message (if it is short),»or lead your response with a clear reference to the original message. Keep your messages relevant to the topic of an - based discussion list or Usenet Newsgroup. Network communication: smileys / emoticons 94 :-) expresses happiness. This odd figure is one of the ways a person can portray mood, in the very flat medium of computers: by using smiley faces = smileys = emoticons, figures created with the symbols on the keyboard. There are literally hundreds of such symbols, from the obvious to the obscure. Read with your head tilted to the left (90 degrees).

48 Examples Network communication: abbreviations used (Part 1) 95 BFN BTW FAQ FUBAR FWIW FYI IAE IMHO IMNSHO bye for now by the way frequently asked question fouled up beyond all recognition for what it's worth for your information in any event in my humble opinion in my NOT so humble opinion Examples Network communication: abbreviations used (Part 2) 96 IMO in my opinion IOW in other words OTOH on the other hand ROTFL roll(ing) on the floor laughing RSN real soon now (may be a long time coming) RTFM read the [f...] manual (or message) TANSTAAFL there ain't no such thing as a free lunch TIA thanks in advance TYVM thank you very much

49 ***-!! Task - Assignment - Exercise!! 97 Try Try to to avoid spam by by reading and and applying the the following guidelines: Center for for Democracy & Technology Why Why am am I I getting all all this this spam? [online] Available from: [cited December 2003] Summary Major findings Tips Tips for for avoiding spam Data communication: overlap among services 98 Electronic mail requires on-line access to a mail computer. Electronic mail may allow searches of a database.»e.g.: archie; listserv databases;... Electronic mail may include or allow transfer of a file.»e.g.: MIME; BITFTP;... Remote login may include and file transfer.»e.g:www; BBS's with downloading;...

50 **** future trends 99 more users availability of global address directories from simple text to multimedia and hypermedia from simple ASCII text to voice , to Internet telephone, to network video-conferencing **** 100 You are free to copy, distribute, display this work under the following conditions:»attribution: You must mention the author.»noncommercial: You may not use this work for commercial purposes.»no Derivative Works: You may not change, modify, alter, transform, or build upon this work. For any reuse or distribution, you must make clear to others the license terms of this work.