Introduction to networking - Ch.3.2 Application Layer, FTP, SMTP, POP and IMAP

Submitted by keithyau on Fri, 01/08/2010 - 15:38


Introduction to networking

FTP: File transfer protocol

  1. Transfer file to/from remote host
  2. Client-server model
  3. RFC 959
  4. FTP port 21
  5. Use TCP transport protocol
  6. Out of band design - Two connection: data connection and control connection
FTP command
  1. User
  2. PASS
  3. List - List directory
  4. RETR - gets file
  5. STOR - puts file
Email 3 major components
  1. User agents -> mail reader, E.g. Outlook express, Thunderbird
  2. Mail servers -> Mailbox, message queue
  3. SMTP - Simple Mail Transfer Protocol -> Send and receive email, port 25
SMTP lab
  1. telnet 25
SMTP support
  1. SMTP only support Text
  2. How to send image / files ? Use MIME - multimedia mail extension








Mail Access protocol
Download email from server to client
  1. Mail access protocol: retrieval from server
  2. POP: Post Office Protocol [RFC 1939] • authorization (agent <-->server) and download
  3. IMAP: Internet Mail Access Protocol [RFC 1730] • more features (more complex) • manipulation of stored msgs on server
  4. HTTP: gmail, Hotmail, Yahoo! Mail, etc. (Webmail)


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