CIT 383: Administrative Scripting

1. Electronic Mail CIT 383: Administrative Scripting CIT 383: Administrative Scripting

2. CIT 383: Administrative Scripting Topics • MTAs • SMTP • Message Stores • POP and IMAP

3. CIT 383: Administrative Scripting MTAs Mail Transport Agents use SMTP protocol • Receive mail from MUAs. • Route mail across internet. Examples • sendmail • postfix • qmail • exim • MS Exchange

4. CIT 383: Administrative Scripting SMTP Example 220 brahms.nku.edu ESMTP Sendmail 8.13.3; Wed, 12 Apr 2006 helo mydomain.com 250 brahms.nku.edu Hello mydomain.com, pleased to meet you mail from: me@mydomain.com 250 2.1.0 me@mydomain.com... Sender ok rcpt to: friend@nku.edu 250 2.1.5 friend@nku.edu... Recipient ok data 354 Enter mail, end with "." on a line by itself Subject: Test From: me@mydomain.com To: friend@nku.edu This is a test. . 250 2.0.0 k3GIcr001606 Message accepted for delivery quit 221 2.0.0 brahms.nku.edu closing connection

5. CIT 383: Administrative Scripting SMTP Commands HELO hostname EHLO hostname MAIL FROM: addr RCPT TO: addr VRFY addr EXPN addr DATA QUIT RSET HELP

6. CIT 383: Administrative Scripting SMTP in Ruby require 'net/smtp' message = <<EOM From: #{from} To: #{to} Subject: smtp test This is a test message. EOM smtp = Net::SMTP.new(server, 25) smtp.start do |smtp| smtp.send_message(message, to, from) end

7. CIT 383: Administrative Scripting Message Store Communication • Receives data from MDA (mail.local, procmail) • Provides data to MAA (IMAP, POP, NFS, web) Types of stores • Files (all messages for a user in one file) • Directories (directory per user) • Databases

8. CIT 383: Administrative Scripting POP and IMAP POP: Post Office Protocol • Simple download protocol for offline reading. IMAP: Internet Mail Access Protocol • Online and offline modes of reading. • Partial message fetch (headers, attachments, etc.) • Message state stored on server, not client. • Multiple mailbox and multiple client support.

9. CIT 383: Administrative Scripting POP3 Example S: +OK POP3 server ready <1896.697170952@dbc.mtview.ca.us> C: APOP mrose c4c9334bac560ecc979e58001b3e22fb S: +OK mrose's maildrop has 2 messages (320 octets) C: STAT S: +OK 2 320 C: LIST S: +OK 2 messages (320 octets) S: 1 120 S: 2 200 S: . C: RETR 1 S: +OK 120 octets S: <the POP3 server sends message 1> S: . C: DELE 1 S: +OK message 1 deleted C: QUIT S: +OK dewey POP3 server signing off (maildrop empty)

10. CIT 383: Administrative Scripting Accessing Mail in Ruby Files (mbox format) require ‘mailread’ mbox = Mail.new(fh) POP require ‘net/pop’ pop = Net::POP3.new(server) pop.start(user, pass) IMAP require ‘net/imap’ imap = Net::IMAP.new(server) imap.login(user, pass)

11. CIT 383: Administrative Scripting References • Michael Fitzgerald, Learning Ruby, O’Reilly, 2008. • David Flanagan and Yukihiro Matsumoto, The Ruby Programming Language, O’Reilly, 2008. • Hal Fulton, The Ruby Way, 2nd edition, Addison-Wesley, 2007. • Robert C. Martin, Clean Code, Prentice Hall, 2008. • Dave Thomas with Chad Fowler and Andy Hunt, Programming Ruby, 2nd edition, Pragmatic Programmers, 2005.