Email Architecture Computer Science YouTube Lecture Handouts

Get unlimited access to the best preparation resource for competitive exams : get questions, notes, tests, video lectures and more- for all subjects of your exam.

Email Architecture

Complete notes and preparation module at

doorsteptutor. com

Objectives: Upon completion you will be able to:

1. Understand the basics of Email and its working

2. Understand the format of message

3. Understand four configurations of email architecture

4. Understand the functions and formats of a user agent

5. Understand the function of POP3

6. Understand the function of IMAP4

7. Advantages of IMAP

8. Understand MIME and its capabilities

9. In brief POP, IMAP, MIME

10. MCQs of Email Architecture

Introduction About Mail

  • It is the service through which messages can be transferred from one person to another person or group of person as per need. There are various facilities that are provided in it.
  • The message need to be sent online but after receiving the receiver can read the messages as he gets time.
  • The messages (mails) will be stored in the inbox until it is deleted by the recipient.
  • It is the electronic mode of transfer of messages over internet.
  • It is very efficient and inexpensive mode of transfer of important messages formally or informally.
  • It is store and forward system.
Introduction About Mail

Format of Message: Two Parts

Format of Message: Two Parts

Architecture of Email

  • Consists of the following components
    • MTA - Mail transfer agent
      • Sending and forwarding emails
      • Server end
    • MDA - Mail delivery agent
      • Delivering emails to recipients՚ mailbox
      • Server end
    • Pop3/Imap4 Daemons
      • For users to download their mailboxs
      • Server end
    • MUA - Mail user agent
      • Reading and composing emails
      • Client end



User Agents

User Agents: User Agents are the clients/users/email readers.

Functions of User Agents:

Functions of User Agents


  • SMTP – Simple Mail Transfer Protocol.
  • It is the Internet standard for electronic mail.
  • It is a connection oriented protocol in which connection need to be made before sending instructions.
  • It is the text based protocol, where messages transfer over the reliable network of message delivery to the recipients from the sender.
  • This channel is typically TCP connection (connection oriented channel) .
  • SMTP Clients generates commands and SMTP transaction consists of 3 commands i.e.. MAIL, RCPT, and DATA.
  • MAIL- It is the command to establish the return address, reverse-path, and envelope sender.
  • RCPT- It is the command to establish a recipient of the message or data.
  • DATA- These are the signals of the beginning of the message text; content of message and it includes header and body (content of message) .

Working of SMTP

Working of SMTP


  • It stands for Post Office Protocol.
  • It is the application layer standard protocol.
  • It is used to retrieve the email from a server (remote source) over a connection oriented path (TCP/IP) .
  • POP3 is the current standard used by modern email clients and servers.
  • POP3 and IMAP are important and standard protocols for email retrieving
  • POP3 can leave mails on server after downloading also, then client can retrieve them, can store them on their system, can perform various activities on them like deleting them and then finally disconnect from the established connection.
  • It is the interface between email clients and the “mail store” (Mail Storage API) is the common interface to the mail store for all processes.
Post Office Protocol


  • It stands for Internet Message Access Protocol.
  • It allows email recipient/client to access email on remote server.
  • It allows both modes of operations: online and offline
  • This provides the facility for multiple clients/hosts to manage the same mailbox.
  • Here, in this case, email clients have messages on server until user explicitly deletes them.

Working of IMAP

Working of IMAP

Advantages of IMAP

Advantages of IMAP
In POP, clients connect to email server, until they download new message.IMAP often connected as long as UI (User Interface) is active and download message.
Useful for large messages
Faster Response
Connected Client is the only clientIt allows for multiple access by multiple clients
It allows clients to retrieve the text message portion without retrieving attached file or to stream content as it is being fetched.
  • It allows multiple mailboxes on the server.
  • Searching mechanism (from server՚s data) is possible
  • IMAP client can create/compose, rename, and copy the messages from mailbox.

Working of SMTP, IMAP and POP3

Working of SMTP, IMAP and POP3


  • It stands for Multipurpose Internet Mail Extensions (MIME) .
  • Virtually all email is transmitted via SMTP in MIME format
  • It is an internet standard that extends the format of email to support various functions and provide facilities like:
Multipurpose Internet Mail Extensions

In Brief

In Brief


Q1. Authentication and Authorization is possible in case of which of the following given protocol?




3. POP3

4. Both 1 and 2

Answer: 1

Q2. Full form of IMAP?


1. Internet Message Accessed Protocol

2. Interconnection Message Access Protocol

3. Internet Message Access Process

4. Internet Message Access Protocol

Answer: 4


0: 00 Email Architecture

0: 50 Introduction about Mail

2: 34 Format of Message: Two Parts

3: 23 Architecture of Email

4: 24 Architecture

5: 20 User Agents

5: 55 SMTP

7: 38 Working of SMTP

8: 00 POP

9: 12 IMAP

9: 45 Working of IMAP

10: 08 Advantages of IMAP

11: 30 Working of SMTP, IMAP and POP3

11: 45 MIME

12: 18 In brief

12: 40 MCQ about Email Architecture

#emailarchitecture #introductionaboutmail #formatofmessage #architectureofemail #architecture #useragents #smtp #workingofsmtp #pop #imap #workingofimap #advantagesofimap #workingofsmtpimapandpop3 #mime #mimeanditscapabilities #mcqaboutemailarchitecture #testprep