              Cyrus IMAP Server:  Alternate Namespace

    This document describes the alternatives to the standard mailbox
    presentation method. These alternatives may be used together or
    independently. 

    The namespace options do NOT change the rules governing the behavior of
    mailboxes (as described in overview.html) or how mailboxes are stored
    on the filesystem. The mailboxes are ALWAYS stored using the netnews
    convention and internal namespace. When configured to use one (or both)
    of the options below, the server simply translates mailbox names
    between the internal names and the external names when used by the
    client in the IMAP protocol and in Sieve scripts. 

    This design allows the namespace to be changed at runtime (even on a
    running server) without having to reconfigure the server. This also
    means that one mailstore can support multiple namespaces if configured
    correctly. 

    NOTE: If you are upgrading an existing server which uses timsieved to
    manage Sieve scripts and choose to enable one of the namespace options,
    you should run the script "tools/translatesieve" after configuring the
    namespace option(s). This script will translate the folder names in
    fileinto actions. 

Alternate Mailbox Namespace

    The alternate namespace allows a user's personal mailboxes to appear as
    if they reside at the same level as that user's INBOX as opposed to
    children of it. For example, if user "bovik" had a personal "work"
    mailbox, it would appear to user "bovik" as "work" instead of
    "INBOX.work" as it would in the standard namespace. 

    This configuration requires that a special prefix be used for shared
    folders (to distinguish them from personal folders) and for accessing
    other users' folders. By default, the prefix for shared folders is
    "Shared Folders" and the prefix for other users folders is "Other
    Users". For example, a shared folder "foo" in the standard namespace
    would be presented as "Shared Folders.foo" in the alternate namespace. 

    NOTE: All tools for administering the server, including admins using
    cyradm, always use the internal namespace. 

Configuring the Alternate Namespace

    To use the alternate namespace, turn on the altnamespace option in
    /etc/imapd.conf. The prefixes used for shared folders and other users
    folders can be changed from the defaults by setting the sharedrefix and
    userprefix options respectively. 

UNIX Hierarchy Convention

    The UNIX hierarchy convention uses the traditional UNIX separator
    character ("/") to delimit levels of the mailbox hierarchy instead of
    the netnews character ("."). For example, if user "bovik" had a
    personal "work" mailbox, it would appear to user "bovik" as
    "INBOX/work" in the standard namespace. 

    When the UNIX hierarchy convention is used, the "." character MAY be
    used in mailbox names, including user names. In order to maintain
    backwards compatibility with the internal namespace, all "." characters
    are translated to a benign character (currently "^") before any data is
    stored to disk. For example, if user "elmer.fudd" had a personal
    "rabbit.holes" mailbox, it would be stored as
    "user.elmer^fud.rabbit^holes" in the internal namespace. It is
    important to remember this phenomenon if/when reverting back to the
    netnews hierarchy convention. 

Configuring the UNIX Hierarchy Convention

    To use the UNIX hierarchy separator, turn on the unixhierarchysep
    option in /etc/imapd.conf. 

