Task 1.21

IMAP4 vs POP3

Internet message access protocol is one of the two most prevalent Internet standard protocols for getting e-mails, the other protocol is Post office protocol. Virtually all modern email clients and mail servers support both protocols as a means of transferring email messages from a server.

POP3	IMAP
Since email needs to be downloaded into desktop PC before being displayed, you may have the following problems for POP3 access: You need to download all email again when using another desktop PC to check your email. May get confused if you need to check email both in the office and at home. The downloaded email may be deleted from the server depending on the setting of your email client.	Since email is kept on server, it would gain the following benefits for IMAP access: No need to download all email when using other desktop PC to check your email. Easier to identify the unread email.
All messages as well as their attachments will be downloaded into desktop PC during the 'check new email' process.	A whole message will be downloaded only when it is opened for display from its content.
Mailboxes can only be created on desktop PC. There is only one mailbox (INBOX) exists on the server.	Multiple mailboxes can be created on the desktop PC as well as on the server.
Filters can transfer incoming/outgoing messages only to local mailboxes.	Filters can transfer incoming/outgoing messages to other mailboxes no matter where the mailboxes locate (on the server or the PC).
Outgoing email is stored only locally on the desktop PC.	Outgoing email can be filtered to a mailbox on server for accessibility from other machine.
Messages are deleted on the desktop PC. Comparatively, it is inconvenient to clean up your mailbox on the server.	Messages can be deleted directly on the server to make it more convenient to clean up your mailbox on the server.
Messages may be reloaded onto desktop PC several times due to the corruption of system files.	The occurrence of reloading messages from the server to PC is much less when compared to POP3.

POP3 maintains a collection of text files - one for each e-mail account. When a message arrives, the POP3 server simply appends it to the bottom of the recipient's file.

Using IMAP an email client program can not only retrieve email but can also manipulate message stored on the server, without having to actually retrieve the messages. So messages can be deleted, have their status changed, multiple mail boxes can be managed, etc.