How to create and manage public folder

How to create and manage public folder

iRedMail has setting for public folder in /etc/dovecot/dovecot.conf, what you need to do is:

enable the setting for public folder
choose a preferred directory as public folder
create ACL file to control the access

In this tutorial, we will show you how to share a public folder named TestFolder.

Enable public folder in Dovecot

Find sample settings like below in Dovecot config file /etc/dovecot/dovecot.conf:

# Public mailboxes.
# Refer to Dovecot wiki page for more details:
# http://wiki2.dovecot.org/SharedMailboxes/Public
#namespace {
#    type = public
#    separator = /
#    prefix = Public/
#
#    # CONTROL=: Mark this public folder as read-only mailbox
#    # INDEX=: Per-user \Seen flag
#    location = maildir:/var/vmail/public/:CONTROL=~/Maildir/public:INDEX=~/Maildir/public
#
#    # Allow users to subscribe to the public folders.
#    subscriptions = yes
#}

Remove comment marks (#) for above namespace {} block, like below:

# Public mailboxes.
# Refer to Dovecot wiki page for more details:
# http://wiki2.dovecot.org/SharedMailboxes/Public
namespace {
    type = public
    separator = /
    prefix = Public/

    # CONTROL=: Mark this public folder as read-only mailbox
    # INDEX=: Per-user \Seen flag
    location = maildir:/var/vmail/public/:CONTROL=~/Maildir/public:INDEX=~/Maildir/public

    # Allow users to subscribe to the public folders.
    subscriptions = yes
}

If you want to share the public folder to all users hosted on same server, please also remove the comment mark in below line in dovecot.conf:

    acl_anyone = allow

Restarting Dovecot service is required after changed its config file.

Important notes:

With above setting, it uses /var/vmail/public as public folder. You're free to change it to a preferred directory. We use /var/vmail/public/ in this tutorial for example.
Please make sure the public folder is owned by user/group vmail:vmail with permission 0700.

Now let's create required folder and our first shared folder TestFolder.

Attention: there's a dot in folder name while creating it, it's .TestFolder, not TestFolder. All folders with a prefixed dot will be considered as an IMAP folder by Dovecot with iRedMail default settings.

mkdir -p /var/vmail/public/.TestFolder
chown -R vmail:vmail /var/vmail/public
chmod -R 0700 /var/vmail/public

Note that there are no cur/, new/ or tmp/ directories directly under the /var/mail/public/, because the Public/ namespace isn't a mailbox itself. (If you create them manually, it does become a selectable mailbox.)

With steps above, if you login to webmail (or other IMAP client) as any mail user hosted on same server, there's no visible public folder at all -- this is correct, because no one has permission to access this folder.

Manage Access Control with `doveadm`

Before we set any permission, let's check the access control of this public folder:

doveadm acl get -A "Public/TestFolder"

You can see output like below, no access control at all:

Username ID Global Rights

With shell command below, we grant lookup, read, write, insert, delete and create (sub-directory) permissions to user postmaster@test.com (again, this user is hosted on same server):

doveadm acl set -A "Public/TestFolder" "user=postmaster@test.com" lookup read write insert delete create

Check the ACl with doveadm now:

# doveadm acl get -A "Public/TestFolder"
Username        ID                       Global Rights
postmaster@a.cn user=postmaster@test.com        create delete insert lookup read write

If you now login to webmail (or other IMAP client) as user postmaster@test.com, you can see a new folder TestFolder.

With shell command below, we grant all users hosted on same server lookup, and read permissions:

doveadm acl set -A "Public/TestFolder" "anyone" lookup read

Check the ACl with doveadm now:

# doveadm acl get -A "Public/TestFolder"
Username        ID                       Global Rights
postmaster@a.cn anyone                          lookup read
postmaster@a.cn user=postmaster@test.com        create delete insert lookup read write

If you login to webmail (or other IMAP client) as any user hosted on same server, you can see a new folder TestFolder.

With shell command below we delete access control for user postmaster@test.com:

doveadm acl delete -A "Public/TestFolder" "user=postmaster@test.com"

For more details about doveadm acl control, please read its manual page.

Manage Access Control manually

Notes:

if you're running Dovecot-2, it's recommended to manage ACL with doveadm command.

Dovecot will create file /var/vmail/public/dovecot-acl-list automatically, it lists all mailboxes that have l rights assigned. If you manually add/edit dovecot-acl files, you may need to delete the dovecot-acl-list to get the mailboxes visible.

Access permission is controlled in file dovecot-acl under each shared folder, let's create it before showing you some examples:

touch /var/vmail/public/.TestFolder/dovecot-acl
chown vmail:vmail /var/vmail/public/.TestFolder/dovecot-acl
chmod 0700 /var/vmail/public/.TestFolder/dovecot-acl

With shell command below, we grant lookup (l), read (r), write (w), insert (i), delete (x) and create sub-directory (k) permissions to user postmaster@test.com (again, this user is hosted on same server):

echo 'user=postmaster@test.com lrwixk' >> /var/vmail/public/.TestFolder/dovecot-acl

With shell command below, we grant all users lookup (l) and read (r) permissions:

Note: it requires setting acl_anyone = allow in Dovecot config file.

echo 'anyone lr' >> /var/vmail/public/.TestFolder/dovecot-acl

References

Dovecot official documents:

How to create and manage public folder

Enable public folder in Dovecot

Manage Access Control with doveadm

Manage Access Control manually

References

See Also

Manage Access Control with `doveadm`