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Simple Mail Transfer Protocol and Post Office Protocol - Version 3 (SMTP and POP3)

Read the E-mail materials, do the experiments: Send an E-mail without using application S/W. Connect to your POP3 server (not the POP3 client which is yourself) and experience the POP3 commands (e.g. message retrivel ).

Concept

Users use below applications

  • Email Agents (e.q. outlook...) to access the Mail Services

but we will not use any client-side applications to access above Services. instead of telnet. It will help us to know more detail of each low-level protocol.

Requirements

  • Red-Hat Linux 6.2 + KDE/X-window

SMTP

Step-by-Step of telnet

  1. Login NTUT's Telnet Server
  2. Telnet to NTUT's SNMP Services (TCP Port 25) 
    # telnet 140.124.13.2 25
  3. Issue SMTP Commands
STEP PROMPT DESCRIPTION
1 helo ntut.edu.tw Initiate the SMTP conversation
2 MAIL FROM: s9360511@ntut.edu.tw Specifies the e-mail address of the sender
3 RCPT TO: s9360511@ntut.edu.tw Specifies the e-mail address of the recipient (send to myself in this case
4 DATA Start the transfer of the message contents, then Server will answer go ahead
5 . A single dot (.) must be sent in a line by itself . ,then Server will answer mail's number in queue
6 QUIT Exit the Mail Server

Screenshot

  • Screenshot
    result

POP3

Step-by-Step

Following above step. After waiting around 10 minutes (depends on setting of Mail Server), we can test POP3 Service.

  1. Login NTUT's Telnet Server

  2. Telnet to NTUT's POP3 Services (TCP Port 110) 

    # telnet 140.124.13.2 110

  3. POP3 Command

STEP PROMPT DESCRIPTION
1 user s9360511 Specifies the USERNAME
2 pass Specifies the PASSWORD
3 LIST List Message (how many) and size of message (according to above, my will have one mail at least
4 RETR 1 Retrieve selected message 1
5 DELE 1 Delete selected message 1 if we will not keep it
6 LIST List Message (how many), there is no message now, beacuse will delete it before
7 QUIT Exit POP3 Service

Screenshot

  • Screenshot
    result
$author:   Ching-Wen (Ed) Lai
$date:     Oct. 2001
$revised:  Mar. 2018
$keywords: computer, networks, network, http, RFC.