Difficulty:Beginner
Applies to:Mail

What are IMAP, POP and SMTP?

 

IMAP

IMAP allows you to access your email wherever you are, from any device. 
When you read an email message using IMAP, you don’t download it, instead, you're reading it from the email server. 
As a result, you can check your email from different devices.
IMAP only downloads a message when you click on it, and attachments aren't automatically downloaded. 
This way you're able to check your messages a lot more quickly than POP.
Also known as Internet Message Access Protocol or IMAP4.

 

POP

POP works by downloading all of your new messages from the server. Once they are downloaded onto the device, they are deleted from the email server. 
This means that after the email is downloaded, it can only be accessed using the same device.
When you attempt to access email from a different device, the messages that have been previously downloaded won't be accessible.
Sent mail is stored locally on the device, not on the email server.
Also known as Post Office Protocol or POP3.

 

SMTP

SMTP is used to send emails across the internet. It is part of the application layer of the TCP/IP protocol. 
Using a process called store and forward, SMTP moves your email on and across networks.
Email software most commonly uses SMTP for sending and either POP3 or IMAP4 to send email.
Despite its age, no real alternative to SMTP exists in mainstream usage.
Also known as Simple Mail Transfer Protocol