Access Control Defaults — Cyrus IMAP 3.0.9 (stable) documentation

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# Access Control Defaults

## Administrators

Regardless of the ACL on a mailbox, users who are listed in the `admins` configuration option in imapd.conf(5) implicitly have the `l` and `a` rights on all mailboxes.

Administrators can also see across domains which normal users cannot.

Warning

An admin user should not be a normal email account.

## Mailbox owners

The user who owns a mailbox folder has additional rights which are set regardless of any additional ACLs. These are:

- l - lookup
- k - create subfolders
- x - delete this folder
- a - administer

These are set in `implicit_owner_rights` of imapd.conf(5).

## Default

For all other mailboxes not owned by a user, any user accessing these mailboxes have the following default privileges:

- l - lookup
- r - read contents
- s - seen

These are set in `defaultacl` of imapd.conf(5).

## Initial ACLs for Newly Created Mailboxes

When a mailbox is created, its ACL starts off with a copy of the ACL of its closest parent mailbox. When a user is created, the ACL on the user’s `INBOX` starts off with a single entry granting all rights to the user. When a non-user mailbox is created and does not have a parent, its ACL is initialized to the value of the `defaultacl` option in imapd.conf(5).

## Other Implicit Rights

Note that some rights are available implicitly, for example ‘anonymous’ always has ‘p’ on user INBOXes, and users always have `la` rights on mailboxes within their INBOX hierarchy.