Email & Communication Protocols (SMTP, IMAP, POP3, MIME)

Question 1

SMTP (Simple Mail Transfer Protocol)

Answer 1

What it does:
📤 Sends emails from a client to a mail server, or between servers.

Port:

Usually uses port 25 or 587 (for secure sending)

Example:
When you click “Send” in Gmail, SMTP delivers the message to the recipient’s mail server.

Question 2

POP3 (Post Office Protocol v3)

Answer 2

What it does:
📥 Downloads emails from the server to the device, then deletes them from the server.

Port:

Port 110, or 995 for encrypted

Best for:
Single-device email access (like old-school Outlook)

Question 3

IMAP (Internet Message Access Protocol)

Answer 3

What it does:
📂 Accesses email on the server, keeping it synced across multiple devices.

Port:

Port 143, or 993 for secure

Best for:
Modern email apps where users check mail from phone, tablet, and PC

Question 4

MIME (Multipurpose Internet Mail Extensions)

Answer 4

What it does:
📎 Allows emails to carry attachments like images, PDFs, and videos.

Why it’s important:
SMTP on its own can only send plain text. MIME turns your email into a rich message with formats and files.