The earliest and the most common store-and-forward application of the Internet is electronic mail (e-mail). Describe how e-mail functions.

Your discussion should include a brief description of e -mail components in terms of a client–server application, e-mail delivery stages, email protocols: (SMTP, POP3, IMAP4, and MIME), and Spam and anti-spam techniques.

Use diagrams, where appropriate, to support your answer.

ii) Assume that Alice from organisation A has an e-mail address alice@a.org and Bob from organisation B has an address bob@b.org . What do you think would happen if Alice sends an email message to Bob, but at the time of sending, the DNS servers authoritative for the domain b.org have been shut down for maintenance?