Free course

Email Protocols Course

Learn how email moves through SMTP, how MIME structures messages, how POP3 and IMAP retrieve mail, and where newer protocols fit.

7 modules · 35 lessons · No signup

Prerequisites: DNS

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What you'll learn

Trace an email from submission to mailbox, read SMTP replies and message headers, compare POP3 with IMAP, and choose a secure protocol for each stage.

Course contents

  1. How email moves

    Follow a message through user agents, submission servers, relays, delivery agents, and mailboxes.

    1. ✓ The parts of an email system
    2. ✓ The envelope and the message
    3. ✓ Follow one email across the Internet
    4. ✓ Protocols along the path
    5. ✓ Check your understanding: the email system

  2. The SMTP conversation

    Read greetings, envelopes, message data, replies, and a complete SMTP transaction.

    1. ✓ Start an SMTP session
    2. ✓ Build the SMTP envelope
    3. ✓ Send message data
    4. ✓ Read SMTP reply codes
    5. ✓ Check your understanding: SMTP

  3. Submission and delivery

    Separate submission from relay, negotiate extensions and TLS, authenticate, queue, and retry mail.

    1. ✓ Submission is not relay
    2. ✓ Negotiate ESMTP extensions
    3. ✓ Protect and authenticate submission
    4. ✓ Queues, retries, and delivery status
    5. ✓ Check your understanding: submission and delivery

  4. Messages and MIME

    Understand headers, bodies, content types, encodings, multipart messages, and attachments.

    1. ✓ Read an Internet message
    2. ✓ Important message fields
    3. ✓ MIME types and transfer encodings
    4. ✓ Multipart messages and attachments
    5. ✓ Check your understanding: messages and MIME

  5. POP3

    Download messages through POP3 states, commands, identifiers, deletion rules, and secure connections.

    1. ✓ The POP3 model
    2. ✓ Authenticate and inspect a maildrop
    3. ✓ Retrieve and delete messages
    4. ✓ Secure POP3 and know its limits
    5. ✓ Check your understanding: POP3

  6. IMAP

    Work with server-side mailboxes, flags, searches, stable identifiers, synchronization, and push updates.

    1. ✓ The IMAP model
    2. ✓ Tagged commands and selected mailboxes
    3. ✓ Fetch, store, and search
    4. ✓ UIDs, synchronization, and IDLE
    5. ✓ Check your understanding: IMAP

  7. Choose the right email protocol

    Compare POP3 and IMAP, then place LMTP, Sieve, JMAP, and provider APIs in the email system.

    1. ✓ Choose POP3 or IMAP
    2. ✓ LMTP and Sieve
    3. ✓ JMAP for mail
    4. ✓ Trace and choose the complete email path
    5. ✓ Check your understanding: choosing email protocols