IMAP vs. POP3 E-mail Accounts

IMAP vs. POP3 Email Accounts

Basically both IMAP and POP are different protocols for handling e-mail. Each has its own unique function and purpose. Protocol allows IMAP to deal with e-mail in a different way than POP does. POP is basically a flow through entity—it just passes on the information to you at your e-mail program. IMAP on the other hand, is interactive with your e-mail program. Let's take a look at the uniqueness of both.

POP

POP stands for "Post Office Protocol". It works very simply. When the POP e-mail server receives e-mail it stores it on the server until you to request it. By simply opening your email program (e.g., Outlook) you request the e-mail from the server by pressing the "Send" or "Receive" button. The e-mail program in essence asks the server if there is any mail waiting. If there is, it tells the server to send it to you.

When the POP server receives your request for mail, it sends the entire message to your e-mail program. Once you receive the email, the message is no longer stored on the server unless you specifically tell it to keep a copy.

IMAP

IMAP stands for "Internet Message Access Protocol". It allows you to download e-mails from the server to your e-mail program the same as POP does. However, the difference is that when you request your e-mail from the server it sends a copy rather than sending the entire e-mail. It keeps a copy of the e-mail on the server while simultaneously keeping a copy on your computer.

You may be wondering what happens if you have certain messages on your local computer and IMAP has different messages on the IMAP mail server? IMAP has built in intelligence to handle this task. When you connect the IMAP mail server with your local computer, it senses that there are differences between the local computer and the mail server. It then synchronizes both so that they have the same information.

For example, if you delete messages, compose more and have sent others, this information will be synced up with the IMAP server so that the IMAP server will delete the copies of the messages that were deleted. By the time you log off the IMAP server you have two complete copies of all of the e-mail tasks performed: one on the IMAP server and one on your local computer.

Advantages

POP	IMAP
Relatively straightforward	Slower but more redundant
Faster (sends your e-mails and gets e-mails from you)	Keeps a copy of everything you do on the server
The downside is that if you lose e-mails on your computer you have lost them forever (unless you have saved a copy on the server)	The downside is that it takes up more space

IMAP (4)	POP3
Stands for 'Internet Message Access Protocol'	Stands for 'Post Office Protocol 3'
Uses port TCP:143	Uses port TCP:110
RFC 1730	RFC 1939
Allows email client to access/ manipulate messages on a server	Allows email client to download emails locally
Saves bandwidth as only email headers are displayed in client.	Consumes bandwidth as entire email message gets downloaded
Since messages are stored in server, email messages are accessible from anywhere	Email message can be viewed from the machine where email was downloaded.