香港六合彩-六合彩 » SlideShare
- 1. E-mail & lists client view Anne Villems University of Tartu, Estonia
- 2. Everybody has used e-mail! But how many have read documents, which set the standards for e-mail? These standards have been set up in the documents: RFC 822 / RFC 821 MIME standards set in RFC 2045/2046/2047/2048 (old verson RFC 1521/1522)
- 3. Mail Standard RFC822 Published in 1982 Lines no longer than 1000 char Message body - plain US-ASCII text Message header lines - plain US-ASCII text Limit on message length
- 4. RFC 822 restrictions no multiple objects in a single message no multi-part message bodies no non-textual bodies no X.400 messages can be gatewayd no multifont messages
- 5. ASCII times are over! Now we want: National language support Possibility to send pictures audiofiles other applications video files multimedia applications
- 6. MIME - Multipurpose Internet Mail Extension RFC 2045-2048 obsolete RFC 1521, 1522,1590 RFC 2045 Format of Internet Message Bodies RFC 2046 Media Types RFC 2047 Message Header Extension for Non-ASCII Text RFC 2048 Registration Procedures To solve RFC822 restrictions without serious incompatibilities with it
- 7. MIME defines new header lines MIME-Version header field: MIME-Version: 1.0 The content type header field to specify the the type and subtype of data in the body: Content-Type: Text/Plain: Charset=ISO-8859-1 Content-Transfer-Encoding field to show how data is encoded Content-Transfer-Encoding: QUOTED-PRINTABLE Content-ID and Content-Description for future use
- 8. “Content type” possible values Text - textual information Image - for transmitting still images (gif,jpeg) Audio - requires audio output device Video - to display moving images, like mpeg Application - information to be processed by application program Multipart - to represent compound, possibly embedded parts Message - an encapsulated message
- 9. Content-transfer-Encoding base64 - every 3 bytes are represented with 4 7-bit ASCII characters quoted-printable - will code only non-ASCII characters in the text, 76char lines 7bit - no coding, already 7bit 8bit - have to be transported as 8-bit binary - as 8bit, but may contain long lines
- 10. Quoted-printable Suitable to present most European languages which are based on ISO 8859-x standard Non-ASCII chars will be coded with 3 chars: ´=´ followed by code in base (16) Examples: Ü =DC ä =E4 ö =F6
- 11. Where to get more info about MIME RFC archive with all RFC-s in plain text: ftp://ftp.carnet.hr/pub/Internet/rfc/ Mark Grand’s “MIME Overview” http://www.mindspring.com/~mgrand/mime.html comp.mail.mime FAQ http://www.cis.ohio-state.edu/text/faq/ usent/mail/mime-faq/
- 12. How e-mail works User Agent (UA) - program, with which human users read, create and manage e-mail Mail Transport Agent (MTA) - handling the movement of messages among computers, non-real-time manner; SMTP - Simple Mail Transfer Protocol - must be installed at every Internet Host
- 13. Working protocols SMTP - primary mechanism for moving mail around TCP/IP network, handles sites with permanent connections SMTP delivers mail, not allows user to collect it - sometimes the latter is more convenient POP, IMAP - fill the gap, they are oriented to serve users when they want
- 14. POP, IMAP Aim - to build a distributed e-mail infrastructure LAN oriented, vendor specific POP - Post Office Protocol, latest version POP3, RFC 1725 (1460) IMAP - the Internet Message Access Protocol, latest version IMAP4, RFC2060 (1731)
- 15. What we want from Mail client? Good user interface advanced text editing spelling checker attachments allowed addressbook (with groups!) MIME uudencode/decode Encryption! + mailing lists pager support multiple accounts multilingual support full text indexing + search message filtering … and more
- 16. …more requirements for mail client: signatures (multiple?) database sophisticated send: send e-mail to all my students who live in Liberty street download headers and delete mail from server based on header info UseNet Newsgroups Live spelling Thesaurus auto-dialing Free Internet Fax Confirmation ability … …
- 17. Mail Clients You can find 28 mail clients in Tucows ultimate software collection for Win95, 13 for Mac and 11 for win 3.x They need from 65K to 4.5M memory Tocows has mirrors in many countries one in Croatia: http://www.hrt.hr/tucows/
- 18. Most popular clients The Pegasus Mail, no fee, version 2.54 http://www.pegasus.usa.com/ FAQ http://www.let.nl/pegasus/faq.html Eudora (Qualcomm Inc.) Eudora Pro 3.0.3 Eudora Light 3.0.3 http://www.qualcomm.com/
- 19. Problems going from Eudora to Pegasus Your Adressbooks are not convertible. There exists Interguru Web-site to help you to convert Eudora nickname file to Pegasus address file: http://www.interguru.com/eudopega.htm
- 20. To compare Mail Clients Stroud’s Mail Client Reviews with about 20 packages reviewed: http://cws.internet.com/32mail-reviews.html Intervue Internet Client reviews: http://www.eqp.com/egrinter.html Tucows has evaluated all packages with 0.5 - 5 cows.
- 21. Some words about Netiquette Be polite! Cite as small part of the letter as possible! DO NOT USE UPPER CASE LETTERS THROUGHOUT THE LETTER Use “smilies”: :-) :-( ;-) Take differencies in the culture into account.
- 22. Questions ??? ??? ???