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Unformatted text preview: he numeric reply code is optional. Here the domain name
is required. The text beginning with Sendmail is optional.)
Next the client identifies itself with the HELO command. The argument must be the fully
qualified domain name of the client host: sun.tuc.noao.edu.
The MAIL command identifies the originator of the message. The next command, RCPT,
identifies the recipient. More than one RCPT command can be issued if there are multiple
The contents of the mail message are sent by the client using the DATA command. The
end of the message is specified by the client sending a line containing just a period. The
final command, QUIT, terminates the mail exchange.
Figure 28.2 is a time line of the SMTP connection between the sender SMTP (the client)
and the receiver SMTP (the server). We have removed the connection establishment and
termination, and the window size advertisements.
The amount of data we typed to our user agent was a one-line message ("1, 2, 3."), yet
393 bytes of data are sent in segment 12. The following 12 lines comprise the 393 bytes
that are sent by the client: file:///D|/Documents%20and%20Settings/bigini/Docu...homenet2run/tcpip/tcp-ip-illustrated/smtp_sim.htm (3 of 23) [12/09/2001 14.47.52] Chapter 28. SMTP: Simple Mail Transfer Protocol Received: by sun.tuc.noao.edu. (4.1/SMI-4.1)
id AA00502; Mon, 19 Jul 93 12:47:32 MST
From: email@example.com (Richard Stevens)
Date: Mon, 19 Jul 1993 12:47:31 -0700
X-Phone: +1 602 676 1676
X-Mailer: Mail User's Shell (7.2.5 10/14/92)
1, 2, 3. file:///D|/Documents%20and%20Settings/bigini/Docu...homenet2run/tcpip/tcp-ip-illustrated/smtp_sim.htm (4 of 23) [12/09/2001 14.47.52] Chapter 28. SMTP: Simple Mail Transfer Protocol Figure 28.2 Basic SMTP mail delivery.
The first three lines, Received: and Message-Id:, are added by the MTA, and the
next nine are generated by the use...
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This test prep was uploaded on 04/04/2014 for the course ECE EL5373 taught by Professor Guoyang during the Spring '12 term at NYU Poly.
- Spring '12