IMAP4 is a recent improvement over POP3 for fetching e-mail messages from an Internet mailserver.
The Internet Message Access Protocol (commonly known as IMAP) is an Internet protocol used for accessing email on a remote server from a local client. IMAP4 and POP3 (Post Office Protocol version 3) are the two most prevalent Internet standard protocols for email retrieval. Both are supported by virtually all modern email clients and servers.
When using POP3, clients typically connect to the email server briefly, only as long as it takes to download any new messages. When using IMAP4, clients often stay connected as long as the user interface is active and download message content on demand. For users with many or large messages, this IMAP4 usage pattern can result in much faster response times. IMAP4 also supports encrypted login mechanisms, which may offer EServer members better security for their passwords. And in addition, for users who tend to connect to e-mail servers from a range of different computers, it can be much more useful, because IMAP keeps all your e-mail messages on the server, so you can look at the same messages from multiple locations and multiple machines until you do one of the following:
- You delete the message from any location.
- You move or filter your mail into an EServer webmail mailbox other than "Inbox".
- You download your mail with a POP3 client that isn't set to "Leave mail on Server".