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IMAP help »

Contents

Q: What is IMAP?

IMAP stands for Internet Message Access Protocol. It is a method of accessing electronic mail or bulletin board messages that are kept on a (possibly shared) mail server. In other words, it permits a "client" email program to access remote message stores as if they were local. For example, email stored on an IMAP server can be manipulated from a desktop computer at home, a workstation at the office, and a notebook computer while traveling, without the need to transfer messages or files back and forth between these computers. More information is available about IMAP from http://www.imap.org/.
Q: How do I access the ICS IMAP server?
Configure your mail client to contact the IMAP server imaplb.ics.uci.edu (port 143). Use your ICS UNIX (Sun) username and password with this server.

Here are some general instructions for how to get started for some popular IMAP clients:

pine
% module load pine
% pine -pinerc .pinerc
edit .pinerc to set inbox-path={imaplb.ics.uci.edu/ssl}

Thunderbird
To configure Mozilla Thunderbird, please go here.

If you already have configured your mail client to retrieve your mail from an ICS server using POP, change your configuration to remove the POP server. If you have other mail clients which access your mail with POP, remove the POP configuration on them also. You should access your mail only with IMAP-based clients.

Q: Can I have multiple IMAP folders? Q: Where are my IMAP folders stored?
IMAP considers the "INBOX" folder name to be special -- it reflects the contents of your newly-delivered mail. While the INBOX name itself is case-insensitive, your mail client may present this name in a particular way (e.g., "Inbox").

You can have other mail folders on the server also. If you don't tell your mail client where to store the mail folders, they'll go in your UNIX home directory.

You will probably want to keep your IMAP folders in a subdirectory (rather than in your home directory). To do this:

  • Go to properties for this server (probably under "Advanced" or "More Options" or something similar) to set the "IMAP mail directory" (this may be called "mail directory prefix", "root folder path" or something similar).
  • Set your "IMAP mail directory" to "imapmail" (or whatever directory you prefer).
  • After changing that setting, you may have to do "resynch folder list" (or some similar function), or quit and restart your mail client before the change will take effect.

If you've used MH before and have a "Mail" directory with MH folders in it, don't use that directory for the IMAP server (it will confuse the server).

Q: What is the format of IMAP folders?
The server stores your mail in "mbox"-type mailbox files. That is, a single IMAP folder is actually multiple messages concatenated into a single UNIX file (with delimiters). When you access a folder, the server reads the entire file into memory. Big folders can take a long time to open.
Q: Can I read UNIX-mail folders I already have?
The IMAP server uses mbox-style folders by default, but it can read and write other formats. After you get your client configured to look in a particular subdirectory for your IMAP mail folders, copy your other UNIX-mail folders into that directory. You may have to quit and restart your mail client, or go to a "subscribed folders" menu and select the folders to get it to notice them.
Q: Can I have a hierarchy of IMAP folders?
Since the IMAP server creates UNIX files for each mail folder, you can have subfolders only if the parent folder contains no messages. That is, in the default configuration the server does not support folders which contain both messages and subfolders. If your mail client has a setting for this option, be sure to set it appropriately.

To create a folder which can contain subfolders (and not messages), create the folder with a trailing slash character in its name (e.g., "subfolders/"). You will then be able to create sub-folders under that folder.

Q: Can I access mail in my MH folders?
The IMAP server can read your MH folders directly. To do this, add a second mail server configuration to your client. Give it the same IMAP hostname (imaplb.ics.uci.edu) but for the "IMAP mail directory" put "#mh/". When you open that server, it should show all your MH folders. You may have to quit and restart your mail client, or go to a "subscribed folders" menu and select the folders to get it to notice them.

Notes:

  • The "inbox" folder in this setup refers only to your MH +inbox folder, not your newly-delivered mail.
  • When accessing mail in MH folders, you can have both messages and subfolders in a folder (just like in MH).
  • When you open an MH folder, the IMAP server reads every message in the folder. Big folders can take a long time to open.
Q: What does "DON'T DELETE THIS MESSAGE" mean?
The IMAP server uses the first message in each IMAP folder to store IMAP folder settings. Normally, the IMAP server doesn't show you that message. If you access your mail another way (e.g., via POP), the POP server doesn't know that the message is special and it downloads it.

You can delete the message. The IMAP server will re-generate it as needed. But, you should disable all POP access to your mail. Use IMAP access only.

Q: My mail client dumped all my mail folders into my home directory, even though I specified another directory in the preferences.
Some users have observed this behavior with some mail clients (in particular, Netscape 4.61). One partial work-around is to set your client to only show "subscribed" folders, then only subscribe to your actual mail folders. This will at least prevent the client from listing every file in your account as though it were a mail folder.
Q: What's a good IMAP mail client?
Whichever one you like best :-). There is a listing of IMAP clients published by the University of Washington IMAP Connection at http://www.imap.org/products/longlist.htm.

In September 1999 Professor David Eppstein tried several Macintosh IMAP clients and provided the following review:

I've tried three so far on the Mac: Mail Drop, Mailstrom, and Mulberry. Mailstrom crashed a few times and doesn't seem to handle subscribed folders. Mulberry has probably the most complete feature set, and a more colorful user interface, but I think Mail Drop is cleaner, so it's the one I'm mainly using. Mail Drop also has the advantage over the other two of being free.

Netscape:

  • + good handling of MIME
  • + good integration of URLs with browser (of course)
  • +/- hierarchical display of subscribed folders reduces clutter but forces more work navigating to the desired folder
  • - paned window format (I prefer separate windows for folders, message headers, and messages -- that way I can make each of them large enough to be useful. Netscape can do this but it's not the default and requires double-clicking everywhere.)
  • - messy unintelligable icons
  • - It can't have more than one folder open at once.
  • - Response to typing in a message subject is very slow (due to it changing the window title after each new character) often leading to dropped characters.

Mail Drop:

  • + cleaner user interface
  • + "intelligent space" scrolls messages (as does Netscape) but also moves to next message when at end of current message
  • + better wrapping of quoted text
  • + better selection of quoted text (selecting some text in a message and then replying quotes wraps only the selected text).
  • + more convenient keyboard shortcuts (for instance NS doesn't have a shortcut for compacting a folder).
  • + better "subscribe" command: I can subscribe by just typing the mailbox name into a dialog, while Netscape forces me to navigate graphically through my (large) directory structure.
  • - forwarded messages are not MIME-encapsulated (and in general its MIME handling seems more primitive than NS)
  • - no online/offline mode switching

One thing I really like about IMAP is the complete lack of hassle in switching from one program to another. So, I see no reason not to use both -- I'll probably stick to Mail Drop as my primary reader, but switch to Netscape when I need its improved MIME handling.

Reviews of other IMAP clients are invited. Please send your review to helpdesk@ics.uci.edu.

Ackowledgements

ICS gratefully acknowledges the assistance of the following individuals who tested and provided feedback about the IMAP server during testing: Celio Albuquerque, Professor David Eppstein, Professor John Gennari, Arthur S. Hitomi, Robb Klashner, Kari Nies, Peyman Oreizy, Shivajit Mohapatra, Professor Wanda Pratt, Nick Savoiu.