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slapo-memberof - Man Page

Reverse Group Membership overlay to slapd




The memberof overlay to slapd(8) allows automatic reverse group membership maintenance. Any time a group entry is modified, its members are modified as appropriate in order to keep a DN-valued "is member of" attribute updated with the DN of the group.

Note that the dynlist overlay can also provide this functionality and may be suitable for less demanding environments.


The config directives that are specific to the memberof overlay must be prefixed by memberof-, to avoid potential conflicts with directives specific to the underlying  database or to other stacked overlays.

overlay memberof

This directive adds the memberof overlay to the current database; see slapd.conf(5) for details.

The following slapd.conf configuration options are defined for the memberof overlay.

memberof-group-oc <group-oc>

The value <group-oc> is the name of the objectClass that triggers the reverse group membership update. It defaults to groupOfNames.

memberof-member-ad <member-ad>

The value <member-ad> is the name of the attribute that contains the names of the members in the group objects; it must be DN-valued. It defaults to member.

memberof-memberof-ad <memberof-ad>

The value <memberof-ad> is the name of the attribute that contains the names of the groups an entry is member of; it must be DN-valued.  Its contents are  automatically updated by the overlay. It defaults to memberOf.

memberof-dn <dn>

The value <dn> contains the DN that is used as modifiersName for internal  modifications performed to update the reverse group membership. It defaults to the rootdn of the underlying database.

memberof-dangling {ignore, drop, error}

This option determines the behavior of the overlay when, during  a modification, it encounters dangling references. The default is ignore, which may leave dangling references. Other options are drop, which discards those modifications that would result in dangling references, and error, which causes modifications that would result in dangling references to fail.

memberof-dangling-error <error-code>

If memberof-dangling is set to error, this configuration parameter can be used to modify the response code returned in case of violation.  It defaults to "constraint violation", but other implementations are known to return "no such object" instead.

memberof-refint {true|FALSE}

This option determines whether the overlay will try to preserve referential integrity or not. If set to TRUE, when an entry containing values of the "is member of" attribute is modified, the corresponding groups are modified as well.

memberof-addcheck {true|FALSE}

This option determines whether the overlay will check newly added entries for membership in any existing groups. This check is useful if populated groups are created in the directory before the entries they reference. The situation often occurs during replication, which may replicate entries in random order. If set to TRUE, every Add operation will search for groups referencing the added entry and populate its memberof attribute with the group DNs. Note that memberof-dangling must be left on its default setting of ignore for this option to work.

The memberof overlay may be used with any backend that provides full  read-write functionality, but it is mainly intended for use  with local storage backends. The maintenance operations it performs are internal to the server on which the overlay is configured and are never replicated. Consumer servers should be configured with their own instances of the memberOf overlay if it is desired to maintain these memberOf attributes on the consumers. Consumers must also be configured to exclude the memberof attribute from replication. (See the exattr option in the consumer configuration.)



default slapd configuration file

Backward Compatibility

The memberof overlay has been reworked with the 2.5 release to use a consistent namespace as with other overlays. As a side-effect the following cn=config parameters are deprecated and will be removed in a future release: olcMemberOf is replaced with olcMemberOfConfig

See Also

slapo-dynlist(5), slapd.conf(5), slapd-config(5), slapd(8). The slapo-memberof(5) overlay supports dynamic configuration via back-config.


This module was written in 2005 by Pierangelo Masarati for SysNet s.n.c.

Referenced By

slapd.overlays(5), slapo-dynlist(5), slapo-nestgroup(5).

2024/05/21 OpenLDAP 2.6.8