smtp mail envelope headers

Bir SMTP mail trafiğinde temel olarak bir mail server' a bağlantı kurulması, alıcı gönderici adreslerinin paylaşılması, mail içeriği vb temel adımlar üzerinden mail transferi gerçekleşmektedir. Buna örnek aşağıdaki gibi bir senaryo paylaşabiliriz.

 

Bu iletişimdeki ( SMTP transaction ) alıcı ( RCPT TO ) ve gönderici ( MAIL FROM ) adreslerinin paylaşıldığı kısma mail envelope denilmektedir.

 

Burada envelope senders MAIL FROM, envelope recipients ise RCPT TO olmaktadır.

 

Client connects to server's SMTP port (25).
Server: 220 staff.uiuc.edu ESMTP Sendmail 8.10.0/8.10.0 ready; Mon, 13 Mar 2000 14:54:08 -0600
Client: helo students.uiuc.edu
Server: 250 staff.uiuc.edu Hello root@students.uiuc.edu [128.174.5.62], pleased to meet you
Client: mail from: johndoe@students.uiuc.edu
Server: 250 2.1.0 johndoe@students.uiuc.edu... Sender ok
Client: rcpt to: jsmith@staff.uiuc.edu
Server: 250 2.1.5 jsmith@staff.uiuc.edu... Recipient ok
Client: data
Server: 354 Enter mail, end with "." on a line by itself
Client:
Received: (from johndoe@localhost)
        by students.uiuc.edu (8.9.3/8.9.3) id LAA05394;
        Mon, 5 Jul 1999 23:46:18 -0500
Date: Mon, 5 Jul 1999 23:46:18 -0500
From: John Doe <johndoe@students.uiuc.edu>
To: John Smith <jsmith@staff.uiuc.edu>
Message-Id: <199907052346.LAA05394@students.uiuc.edu>
Subject: This is a subject header.

This is the message body.  It is seperated from the headers by a blank
line.

The message body can span multiple lines.

.
Server: 250 2.0.0 e2DKuDw34528 Message accepted for delivery
Client: quit
Server: 221 2.0.0 staff.uiuc.edu closing connection