Courier-IMAP + Global Shared Folders
====================================

Shanker Balan
http://shankerbalan.com/

Overview
========

(From maildirmake(1))

"This is another extension to the Maildir format that allows folders to be
shared between multiple clients."

This allows users to use the IMAP server as a pseudo list server for quickly
reaching everyone without going thru an elaborate newsgroup or mailing list.
Currently, I am using shared folders to publish notices to all users.

Configuration
=============

- The global shared folder holder is in /home/shared-maildirs/
- /home/shared-maildirs/Notices is the root Maildir which contains many more
  shared folders.
- /home/shared-maildirs/Notices/.Domain.com contains is the actual shared
  folder mean for posting messages. This will be world writeable.

[root@mail Notices]# mkdir -p /home/shared-maildirs/
[root@mail Notices]# maildirmake -S /home/shared-maildirs/Notices
[root@mail Notices]# maildirmake -s write -f Domain.com /home/shared-maildirs/Notices

[root@mail root]# ls -ld /home/shared-maildirs/
drwxr-xr-x    3 root     root         4096 Oct 13 12:47 /home/shared-maildirs/
[root@mail root]# ls -ld /home/shared-maildirs/Notices/
drwxr-xr-x    6 root     root         4096 Oct 13 12:47 /home/shared-maildirs/Notices/
[root@mail root]# ls -ld /home/shared-maildirs/Notices/.Domain.com/
drwxr-xr-t    5 root     root         4096 Oct 13 12:23 /home/shared-maildirs/Notices/.Domain.com

*** Courier-IMAP Configuration ***

[root@mail Notices]# echo "Notices /home/shared-maildirs/Notices" > /usr/lib/courier-imap/etc/maildirshared 
[root@mail Notices]# cat /usr/lib/courier-imap/etc/maildirshared 
Notices /home/shared-maildirs/Notices

Restart the Imap service.

Accessing Shared IMAP Folders
=============================

You will have to "subscribe" to this folder if it does not automatically appear
in your mail client. Use your mailer's "Post Message To Folder" feature to post
messages to the shared folder. Since the posting procedure varies from mailer
to mailer, please refer to the user documentation for specifics.

Client Testing via IMAP
=======================

See http://www.inter7.com/courierimap/README.imap.html for client compatibility
notes.

- Evolution 1.4.5: SUCCESS

    The shared folder was listed automatically when I created a new IMAP
    account. In the case of an existing account, the new shared folder had to
    subscibed manually. Posted a message to the shared folder using "New->Post
    Message" (CTRL+SHIFT+P) function successfully.

    URL: http://www.ximian.com/products/ximian_evolution/

- HushMail 0.6: SUCCESS

    The folder dropdown list listed the newly added shared folders on login.
    HushMail is considered to be a really fast, secure and simplistic webmailer
    but I personally found it *too* simple. My users are def not gonna use
    HushMail.

- Sqwebmail 3.6.0: SUCCESS

    Sqweb would be the apt choice with Courier-IMAP, unfortunately, it requires
    direct accesss to the Maildirs which is not possible in my case. The
    webmailer and the mail store are on differrent hosts.

    SqwebMail is a web CGI client for Maildir and not IMAP.

- Squirrelmail 1.2.11: FAILURE

    The default webmail shipped with RedHat 8 did not automatically list the
    shared folders when I logged in. I am not too sure whether it supports the
    shared folder extension. Need to find a more featureful webmailer which
    supports more IMAP extensions.

- Outlook: TODO

- Mozilla: TODO

NOTES
=====

- Shared folders are stored under /home to simplify backups. The maildirmake(1)
  man page suggests using /usr/local/share/maildirs/ which I think is more
  appropriate for this purpose.

- I dont know how to create user shared maildirs via the IMAP client. AFAIK,
  the user has to have shell access to the "maildirmake" commands before he can
  export it.

- SqWebMail (The preferred webmailer with Courier-IMAP) I think supports the
  shared folder extension but I cant use it on my site since the IMAP server
  and the webmail server are on different hosts. SqWebMail does direct Maildir
  access.

Changelog:

* Mon Oct 13 13:30:53 IST 2003
- First cut