IMAP is the primary (and soon to be only) method of mail access on the TCB systems. Virtually every major mail client is compatible with IMAP, a variety of servers can be run on the back-end without the knowledge of the client, and the transactions can be easily secured with SSL (using the IMAP/S port).

General IMAP docs can be found at

General Client Configuration

The IMAP server runs on We only allow secure IMAP access to the server (IMAP/S) to ensure that user passwords are not easily intercepted.

In some cases, your client may want to know which directory to look for your mail in, known as a "mail folder prefix". You'll want to set this to /home/USERNAME/imap/. Your inbox is merely INBOX, no prefix.

Outgoing mail is described here.

Specific Client Configuration


Mutt is a very nice Unix-based mail client - it's the one used by most of the sysadmin team, for those keeping score. It's set up on the Suns and Linux boxes. To use mutt with IMAP, you simply set these two lines near the beginning of your muttrc:

set spoolfile=imaps://
set folder=imaps://

Note that this can be accomplished by using the default system muttrc, by including this line in your .muttrc:

source /Common/shared/mail/muttrc

These options use secure IMAP for mutt's work. If you want to access one of your other imap folders, just add lines like this:

mailboxes =outgoing =sysadmin =testing

And then run mutt with mutt -y to see the list of all mailboxes. More information is available with man mutt.


Pine is another Unix mailer, probably the most common on campus Unix systems. It's available on the Suns and Linux boxes. To use Pine with our IMAP server, edit your local .pinerc to set your 'inbox-path':


If you want to use multiple mailboxes on different servers, you can set the username with /user=USERNAME as part of the above string.

You may also want to set your SMTP server this way:


Eudora is a Windows/Mac mail client initially developed at UIUC. The evaluation version includes on-screen ads, but the UIUC Site Licensed Software page includes a link to download the full version for anybody affiliated with the University (staff, students, faculty).

Help is available within the program. Some configuration issues:

  • With Eudora, you create a profile for each user/mail address. The profile named <<dominant>> is checked by default. The others can either be made to check by default, or check on command. These profiles are called "personalities".
  • You'll probably want to save a copy of outgoing messages back to the server. To do this, create a Eudora filter which looks at all outgoing mail and redirects a copy of the message to the folder outgoing (or similar) on the server. This isn't as tricky as it sounds, just work in the Filter menu for a bit.
  • Each personality also has a mail folder prefix. I have mine set to /home/brunner/Mail/. I can then press the refresh button in the Mailboxes window, to refresh my list of files and folders under the Mail directory. By default, there is a folder called Inbox, that contains the mail in the incoming spool.
  • If you check the option to "save Trash on server" it will move deleted messages to a selected mailbox on the server, rather than on the local disk. This mailbox will get flushed when Empty Trash is selected, or at various other times, depending on other settings (at exit, for example). The file name used for Trash is selected the first time you try to delete a message, and since you can only suggest existing mailboxes, you should create the trash mailbox before throwing anything away.
  • Unset "use background threading" in the Checking Mail section of the settings panel to remove problems associated with doing two things at once.
  • Mac OS 9: Eudora has a few conflicts with MacOS restricted users mode. The fix is documented in the Eudora news group, but takes some work to find. The solution is to install the Esoteric Setting plug-in (by moving it from the Extra Plugins folder to the Eudora Stuff folder in the Eudora Application folder. Then restart Eudora, and you'll see many new settings in the Settings menu. Find the Open Transport settings, and disable all the options there. Also, glance though all the other options, and turn off anything concerning multiple threads.
  • Multiple users: Eudora does not handle multiple users particularly gracefully. To have multiple users on the same machine, you must have different configurations for each user, and access Eudora by loading that configuration file. This is tricky, but I'll work through it soon and document it.

IMAP Server Configuration


  • We are currently using the 2002 IMAP distribution from the University of Washington.
    • Installed on mailhost's encap tree only.
    • Build instructions are in the encap (on mailhost).
    • The only major changes were to make sure it looks in the 'imap' directory by default, and to use PAM for authentication.
  • Runs out of inetd; the relevant section of inetd.conf:
    imaps   stream  tcp     nowait  root    /usr/local/sbin/imapd imapd


  • Tim wrote and configured most of this
  • Rob wrote the Eudora configuration details.

Links and References