IMAP: What's New in Electronic Mail

Eudora 4 for Mac didn't support IMAP but Eudora 5 for Mac does, and does it well. See Configuring Eudora for Macs for IMAP. Configuring Eudora for Windows for IMAP tells you have to configure and use Eudora for Windows with IMAP. It's also useful if you're using other email programs. I've configured Netscape and Outlook using the info in that page.

But if you're tired of excuses, you're in luck. Now you can keep all your email (new, old, saved, and sent) in one central place, one that you can get at from the office, from home, and from on the road, one that will be backed up automatically on a regular basis, and still keep all the amenities of reading, deleting, and sending your mail from a desktop machine. From two or three of them, even!

The answer comes with a new acronym, IMAP. IMAP stands for Internet Message Access Protocol. Like POP (Post Office Protocol), IMAP describes how a mail client program interacts with the central email service machine where you retrieve your messages. IMAP is really good at eliminating email excuses. And the good news is that the new version of Eudora speaks IMAP (4.x for Windows only; not for Macs so far, sorry!) and so do the ACCC email servers (as well as pine, Netscape 4.5, and others).

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Personal computers, however, are flexible and friendly, so someone had a great idea: deliver email messages to the central server, but put the email-reading software on a personal computer. Use the central server for its reliability and availability, and use client software on the personal computer for its flexibility. This is where Eudora and other personal computer email software came in.

When it comes to splitting email functions between the central email server and the personal computer, there's one crucial question: where should the "official copy" be kept?

Should the mail be moved to the personal computer and erased from the server?

Should the mail be left on the server and temporarily copied to the personal computer?

Or should the mail be left on both the server and the personal computer and somehow be synchronized?

The original versions of Eudora used POP, which operates in offline mode: all email messages are copied to the personal computer and erased from the server. This is great if you only do email on one personal computer and if it has a big hard drive. Then you can hold a huge amount of mail on your personal computer, and everything will be reasonably fast once all your messages are downloaded.

The problem with POP is that it overlooks some of the advantages we had when we were doing email on a central server. One important advantage of online access (and one that's missing from any type of offline access) was that we could get at our email from anywhere (well, anywhere that had a sufficient telnet client). So IMAP was born, specifically to make online access feasible.

Of course, when you use IMAP, you can (and do) still download copies of your mail to your personal computer; IMAP's major innovation is that it gives your email client program (running on your personal computer) a lot more control over what's done to your email messages and mailboxes on the central server. And, of course, because the mail is always kept on the central server, you can read it from any location on the Internet.

So it seems that we've come full circle. At first, email was all on the mainframe, and stayed there. With IMAP, email is on the central server, and stays there. The key difference is that our email-reading program can now use the features of the personal computer.

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But those are rather substantial "ifs". If you currently use POP, I'll bet you've had to wait a time or two while your mail client downloaded 50 new incoming messages from the email service machine or while it downloaded a huge MIME attachment that you didn't want. Anyone who has tried to use POP's pseudo-online mode of operation with Eudora's "leave mail on server" option knows how inadequate it can be. And POP mail clients only give you access to the incoming mail in your maildrop, not any other mailboxes you might have on the server.

IMAP was designed to support online operation, so:

IMAP allows you to keep both your incoming mail and all your other mailboxes and folders on the central email service machine, where the IMAP server will take care of them for you. Because the central machine is always running and available on the Internet, you'll always be able to access to all your email, whether you're at home, at the office, or anywhere on the Internet.

IMAP treats all the mailboxes that you have on the central email service machine (both your maildrop and your other mailboxes) as if they were local to your client machine. This means that you can list, create, delete, and rename the mailboxes that you keep on the email service machine using your IMAP client on your desktop machine, including mailboxes you originally created on the server with pine. And yes, of course, you can keep some of your mailboxes on your personal computer, although these local mailboxes will not be managed by IMAP. (See figure 1.) You can even move messages to and from the server machine. In and out of your maildrop, too!

IMAP allows you to use different email programs from different locations. Use Eudora from the office and at home, Netscape at a friend's house, or telnet to tigger when you're traveling and use pine.

IMAP's support of online processing (its allowing you to leave all your email on the central service machine) is a security plus. Your account on the email service machine is password protected; as long as you don't tell other people your password (and don't have your email client remember it!), no one else will be able to read your mail. So you can work on personal computer -- even a shared one -- and still keep your privacy.

IMAP works well over slow Internet connections. Information is sent in small pieces and only as needed. For example, you can delete spam messages without downloading them (IMAP only needs the message headers to build mailbox indexes), and you can read messages without downloading any attachments they might have.

IMAP supports "concurrent updates and access to shared mailboxes". Do you share responsibility for a secondary netid or email from a Web page with a number of people? Instead of sending a copy to everyone and perhaps duplicating efforts, send them to one person, who saves them in a special mailbox on the server. IMAP will allow everyone who needs the mailbox to access it at the same time. (Are you interested? Ask and we'll tell you how.)

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The main advantage that POP has over IMAP is that there are currently more, better, friendlier POP email client software programs available. That is clearly changing now that Eudora supports IMAP (as does pine and Netscape Communicator 4.5 and MS Outlook, and more every day).

And now comes my confession. I prefer IMAP to POP so much that I've been using a personal computer IMAP mail client program for several years: Washington University's PC Pine, first under OS/2 and then under Windows NT. PC Pine is exactly like UNIX pine. For me, IMAP's conveniences far outweighed PC Pine's primitive user interface. But now with Eudora 4 (for Windows only, remember), I have Eudora's GUI and IMAP too -- a winning combination!

Comments are welcome; please send them to
Judith Grobe Sachs, judygs@uic.edu