7 - Email - Last Lecture Start the Application Layer DNS...

Info iconThis preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon
Last Lecture Start the Application Layer DNS SUNY at Buffalo; CSE 489/589 – Modern Networking Concepts; Fall 2010; Instructor: Hung Q. Ngo 1
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This Lecture SMTP SUNY at Buffalo; CSE 489/589 – Modern Networking Concepts; Fall 2010; Instructor: Hung Q. Ngo 2
Background image of page 2
Electronic Mail Infrastructure SUNY at Buffalo; CSE 489/589 – Modern Networking Concepts; Fall 2010; Instructor: Hung Q. Ngo 3 Four major components: o User agents o Mail servers o SMTP o Mail access protocol IMAP/POP3 User Agent (“Mail Reader”) Composing, editing, reading mail messages E.g., Eudora, Outlook, Pine, Thunderbird, Apple Mail user mailbox outgoing message queue mail server user agent user agent user agent mail server user agent user agent mail server user agent SMTP SMTP SMTP SMTP (25) ESMTP (587) Secure SMTP (465) IMAP/POP3
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Typical Scenario: Alice Emails Bob SUNY at Buffalo; CSE 489/589 – Modern Networking Concepts; Fall 2010; Instructor: Hung Q. Ngo 4 1) Alice uses UA to compose message to bob@someschool.edu 2) Alice’s UA sends message to her mail server; message placed in message queue 3) Client side of SMTP opens TCP connection with Bob’s mail server How does it know IP of Bob’s mail server? 4) SMTP client sends Alice’s message over the TCP connection 5) Bob’s mail server places the message in Bob’s mailbox 6) Bob invokes his user agent to retrieve the message There are often more than 1 mail server on the path (follow MX preference) user agent mail server mail server user agent 1 2 3 4 5 6
Background image of page 4
Mail Servers SUNY at Buffalo; CSE 489/589 – Modern Networking Concepts; Fall 2010; Instructor: Hung Q. Ngo 5 Typical functionalities o Mailbox contains incoming messages for user o Message queue of outgoing (to be sent) mail messages o SMTP protocol between mail servers to send email messages “Client”: sending mail server “Server”: receiving mail server mail server user agent user agent user agent mail server user agent user agent mail server user agent SMTP SMTP SMTP
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
SMTP Uses TCP to reliably transfer email message from client to server, port 25 Three phases of transfer o handshaking (greeting) o transfer of messages o closure Command/response interaction o Commands (or Verb) : ASCII text o Response : status code and phrase o 200-399: acceptance o 400-499: temporary rejection o 500-599: permanent rejection Messages must be in 7-bit ASCII SUNY at Buffalo; CSE 489/589 – Modern Networking Concepts; Fall 2010; Instructor: Hung Q. Ngo 6
Background image of page 6
Sample SMTP Interaction [hungngo@saigon] ~ $
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 8
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 12/03/2010 for the course CS 489 taught by Professor Hungngo during the Fall '10 term at SUNY Buffalo.

Page1 / 18

7 - Email - Last Lecture Start the Application Layer DNS...

This preview shows document pages 1 - 8. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online