1 / 13

CPET 355 Data Communications & Networking

CPET 355 Data Communications & Networking. 7. The Application Layer: Email Paul I-Hai Lin, Professor Electrical and Computer Engineering Technology Purdue University, Fort Wayne Campus. Electronic Mail. ARPANET e-mail proposals (1982) RFC 821 – transmission protocol

rian
Download Presentation

CPET 355 Data Communications & Networking

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. CPET 355Data Communications & Networking 7. The Application Layer: Email Paul I-Hai Lin, Professor Electrical and Computer Engineering Technology Purdue University, Fort Wayne Campus Prof. Paul Lin

  2. Electronic Mail • ARPANET e-mail proposals (1982) • RFC 821 – transmission protocol • RFC 822 – (message format) • RFC 2821 and RFC 2822 • Minor revisions of RFC 821 and 822 • Internet e-mail standards Prof. Paul Lin

  3. E-Mail Architecture and Services • Two Subsystems • User agents – local programs • Message transfer agents • Five Basic Functions • Email composition • Transfer • Reporting • Displaying • Disposition Prof. Paul Lin

  4. E-Mail Architecture and Services • Email Envelope • Destination address • Priority level • Security level • Message (inside the envelope) • Header (control info for user agent programs) • Body – the message Prof. Paul Lin

  5. RFC 2822 • Header (related to message transport) • TO: Primary recipients • Cc: Secondary recipients • Bcc: Blind carbon copy • From: Person who created email • Sender: E-mail address of the actual sender • Received: Transfer agent added info • Return-Path: A path back to the sender Prof. Paul Lin

  6. RFC 2822 • Message Header • Date: the date and time the message was sent • Reply-To: the email address to be replied • Message-Id: unique message reference ID • In-Reply-To: message ID • References: other relevant message IDs • Keywords: user-chosen keywords • Subject: short message for one-line display Prof. Paul Lin

  7. MIME- Multipurpose Internet Mail Extensions • Five Message Headers • MIME-Version: 1.0 • Content-Description: Human-readable string telling what is in the message • Content-Id: Unique Identifier • Content-Transfer-Encoding: 5 schemes • Content-Type: 7-types defined in RFC 2045 Prof. Paul Lin

  8. MIME- Multipurpose Internet Mail Extensions • Content-Type: 7-types defined in RFC 2045 • Text: plain, enriched • Image: gif, jpeg • Audio: basic • Video: Mpeg • Application: Octet-stream, Postscript • Message: Rfc822, Partial, External-body • Multipart: Mixed, Alternative, Parallel, Digest Prof. Paul Lin

  9. MIME- Multipurpose Internet Mail Extensions • Content-Type:text/subtype Examples • Content-Type:text/plain • Content-Type:text/enriched • Content-Type:text/html - RFC 2854 • Content-Type:text/xml - RFC 3023 Prof. Paul Lin

  10. MIME- Multipurpose Internet Mail Extensions • Content-Type:image/subtype Examples • Content-Type:image/gif • Content-Type:text/jpg • Content-Type:audio/subtype Examples • Content-Type:audio/basic • Content-Type:audio/mpeg - RFC 3003 Prof. Paul Lin

  11. Message Transfer • SMTP – Simple Mail Transfer Protocol • TCP Port 25 • < 64 KB message length • Time-out issue • Assume that the hosts are on-line all the time • ESMTP – Extended SMTP (RFC 2821) • To get around these SMTP related problems Prof. Paul Lin

  12. Final Message Delivery • POP3 – Post Office Protocol Version 3 • RFC 1939 • ISP’s POP server port 110 • Download emails to the user machine • IMAP – Internet Message Access Protocol • RFC 2060 • Port 143 • For creating, destroying, and manipulating multiple mailboxes on the server • Webmail Prof. Paul Lin

  13. Delivery Features • Filters (rules – conditions, actions) • Spam (junk-email) • Forwarding emails (vacation daemon) Prof. Paul Lin

More Related