Electronic Messaging

• The electronic message
• Envelope
• Header
• Message Body
• The electronic message delivery system
• User Agents
• Message Transfer System
• Message Transfer Agents
• Message Store
• Access Units
• Physical Delivery Access Unit
• Protocols

P1: MTS Transfer protocol

defines communication between a pair of MTAs

P2: IPMS protocol

describes communication between a pair of UAs for the purpose of interpersonal message exchange. P2 is an instance of a class of protocols that are application specific. It applies to interpersonal message systems. Other such protocols are required for other types of message handling systems applications.

P3: MTS Access Protcol

provides access to the MTS by a UA or an MS. Interaction may be initiated by either the MTS or by the UA or MS.

P7: MS Access Protocol

describes access to the MS by a UA. Access is initiated by the UA

Examples of Submission and Delivery

Verbatim Mail Delivery

72 /mnt/a/cassel> mail -v cassel%acm.org@monet.vill.edu
Subject: mail test

What will happen
Cc:
cassel%acm.org@monet.vill.edu... Connecting to monet.vill.edu.tcploc...
220 monet.vill.edu    Sendmail 4.1/SMI-4.1 ready at Mon, 19 Feb 96 10:19:13 EST
>>> HELO tiger.vill.edu
250 monet.vill.edu    Hello tiger.vill.edu ([153.104.7.161]), pleased to meet yo
u
>>> MAIL From:
250 ... Sender ok
>>> RCPT To:
250 ... Recipient ok
>>> DATA
354 Enter mail, end with "." on a line by itself
>>> .
250 Mail accepted
>>> QUIT
221 monet.vill.edu    delivering mail
cassel%acm.org@monet.vill.edu... Sent

Another Mail Test

73 /mnt/a/cassel> mail -v cassel@acm.org
Subject: Another Test
Mail test
Cc:
cassel@acm.org... Connecting to ucis.vill.edu.tcprem...
cassel@acm.org... Deferred: Connection refused by ucis.vill.edu

(Message inbox:2880)
Return-Path: cassel@tiger.vill.edu
Received: from wild.ucis.vill.edu by tiger.vill.edu id ; Mon, 19 Feb 96 13:44:47 EST
Received: from ACM.ORG [192.135.174.1] by ucis.vill.edu
           with SMTP-OpenVMS via TCP/IP; Mon, 19 Feb 1996 13:48 EST
Received: from ucis.vill.edu (LUTHER@wild.ucis.vill.edu)
 by ACM.ORG (PMDF V5.0-6 #10219) id <01I1ECAKP3AO0004ER@ACM.ORG> for
 cassel@ACM.ORG; Mon, 19 Feb 1996 12:49:50 -0600 (CDT)
Received: from monet.vill.edu    [153.104.7.173] by ucis.vill.edu with
 SMTP-OpenVMS via TCP/IP; Mon, 19 Feb 1996 13:42 -0500 (EST)
Received: from tiger.vill.edu ([153.104.7.161])
 by monet.vill.edu    (4.1/SMI-4.1) id AA13340; Mon,
 19 Feb 1996 10:19:13 -0500 (EST)
Received: by tiger.vill.edu id ; Mon,
 19 Feb 1996 10:11:14 -0500 (EST)
Date: Mon, 19 Feb 1996 10:11:14 -0500 (EST)
From: cassel@tiger.vill.edu
Subject: mail test
To: cassel%acm.org@monet.vill.edu
Message-Id: <9602191511.AA20385@tiger.vill.edu>
Content-Transfer-Encoding: 7BIT


What will happen

Message Envelope

• Originator
• Recipient
• Content type
• UA content id
• priority
• flags specifying permitted operations
• delivery deadline
• others
• Example of a malformed header

Message Heading

• Message ID
• originator
• Primary recipients
• Copy recipients
• Blind copy recipients
• In Reply To
• Obsoletes
• Cross References (links to earlier communications)
• Subject
• Expiration date
• Reply by (deadline for response)
• Reply to users (list of users who should get any response
• Importance -- high, medium, or low
• Sensitivity -- personal, private, or confidential

Message Body

cassel@vill.edu