TUX.RE Forum

If you're setting up email for the first time, you’ll often see terms like POP3, IMAP, and SMTP.
They sound complicated, but the idea behind them is actually quite simple.

What is POP3?

POP3 (Post Office Protocol) is a method to download emails from a server to your device.

How it works:
Your email client connects to the server
Downloads your messages
Usually removes them from the server afterward
Good for:
Using email on one single device
Keeping emails stored locally
Downsides:
Emails are not synced across devices
If you check mail on your phone, it may not appear on your PC

POP3 is older and less common today.

What is IMAP?

IMAP (Internet Message Access Protocol) is the modern way to handle email.

How it works:
Emails stay on the server
Your devices sync with the server
Actions like “read”, “delete”, or folders are shared across all devices
Good for:
Using email on multiple devices
Webmail access like Roundcube
Modern email setups
Downsides:
Requires more server storage

IMAP is the recommended option for most users today.

What is SMTP?

SMTP (Simple Mail Transfer Protocol) is used to send emails.

How it works:
Your email client sends a message to a mail server
The server delivers it to the recipient’s mail server

Important:

SMTP is only for sending, not receiving
Every email you send goes through SMTP
How they work together

Think of it like this:

SMTP → sends your email
IMAP or POP3 → lets you read your email
Example

If you use a mail service:

You send emails using SMTP
You read emails using IMAP (recommended) or POP3
Webmail tools like Roundcube use both in the background

Summary
POP3 → downloads emails to your device
IMAP → keeps emails synced across devices
SMTP → sends emails