Homework 8

Sockets, TPC, and Internet programming: Mail.

• The nature of the Internet. How it came about. Who does it.
• The IETF and RFC's.
• What are protocols.
• RFC 821: Simple Mail Transfer Protocol, by Jon Postel.
• RFC 822: Standard for the Format of ARPA Internet text messages, by David Crocker
• An example mail transfer.

  [burt@lee tmp]$ telnet localhost 25
  Trying 127.0.0.1...
  Connected to localhost.localdomain (127.0.0.1).
  Escape character is '^]'.
  220 lee.cs.miami.edu ESMTP Sendmail 8.13.1/8.13.1; Tue, 19 Apr 2005 14:47:48 -0400
  HELO lee.cs.miami.edu
  250 lee.cs.miami.edu Hello lee [127.0.0.1], pleased to meet you
  MAIL FROM:<burt@disney.orgi>
  250 2.1.0 <burt@disney.org>... Sender ok
  RCPT TO:<burt@cs.miami.edu>
  250 2.1.5 <burt@cs.miami.edu>... Recipient ok
  DATA
  354 Enter mail, end with "." on a line by itself
  From: burt@nowhere.org
  To: burt@cs.miami.edu
  Subject: nice day
  
  Hi
  .
  250 2.0.0 j3JIlmAn011598 Message accepted for delivery
  QUIT
  221 2.0.0 lee.cs.miami.edu closing connection
  Connection closed by foreign host.
  [burt@lee tmp]$ 
  

• This is what ends up in the mailbox

  Return-Path: <burt@disney.org>
  X-Original-To: burt@cs.miami.edu
  Delivered-To: burt@cs.miami.edu
  Received: from lee.cs.miami.edu (lee.cs.miami.edu [172.19.0.2])
  	by sherman.cs.miami.edu (Postfix) with SMTP id 83706AD29
  	for <burt@cs.miami.edu>; Tue, 19 Apr 2005 14:49:39 -0400 (EDT)
  Received: from lee.cs.miami.edu (lee [127.0.0.1])
  	by lee.cs.miami.edu (8.13.1/8.13.1) with SMTP id j3JIlmAn011598
  	for <burt@cs.miami.edu>; Tue, 19 Apr 2005 14:48:22 -0400
  Date: Tue, 19 Apr 2005 14:47:48 -0400
  Message-Id: <200504191848.j3JIlmAn011598@lee.cs.miami.edu>
  From: burt@nowhere.org
  To: burt@cs.miami.edu
  Subject: nice day
  
  Hi