SLAPO-CONSTRAINT(5)           File Formats Manual          SLAPO-CONSTRAINT(5)

       slapo-constraint - Attribute Constraint Overlay to slapd


       The constraint overlay is used to ensure that attribute values match
       some constraints beyond basic LDAP syntax.  Attributes can have
       multiple constraints placed upon them, and all must be satisfied when
       modifying an attribute value under constraint.

       This overlay is intended to be used to force syntactic regularity upon
       certain string represented data which have well known canonical forms,
       like telephone numbers, post codes, FQDNs, etc.

       It constrains only LDAP add, modify and rename commands and only seeks
       to control the add and replace values of modify and rename requests.

       No constraints are applied for operations performed with the relax
       control set.

       This slapd.conf option applies to the constraint overlay.  It should
       appear after the overlay directive.

       constraint_attribute <attribute_name>[,...] <type> <value> [<extra>
              Specifies the constraint which should apply to the comma-
              separated attribute list named as the first parameter.  Five
              types of constraint are currently supported - regex, size,
              count, uri, and set.

              The parameter following the regex type is a Unix style regular
              expression (See regex(7) ). The parameter following the uri type
              is an LDAP URI. The URI will be evaluated using an internal
              search.  It must not include a hostname, and it must include a
              list of attributes to evaluate.

              The parameter following the set type is a string that is
              interpreted according to the syntax in use for ACL sets.  This
              allows one to construct constraints based on the contents of the

              The size type can be used to enforce a limit on an attribute
              length, and the count type limits the number of values of an

              Extra parameters can occur in any order after those described

              <extra> : restrict=<uri>

              This extra parameter allows one to restrict the application of
              the corresponding constraint only to entries that match the
              base, scope and filter portions of the LDAP URI.  The base, if
              present, must be within the naming context of the database.  The
              scope is only used when the base is present; it defaults to
              base.  The other parameters of the URI are not allowed.

       Any attempt to add or modify an attribute named as part of the
       constraint overlay specification which does not fit the constraint
       listed will fail with a LDAP_CONSTRAINT_VIOLATION error.

              overlay constraint
              constraint_attribute jpegPhoto size 131072
              constraint_attribute userPassword count 3
              constraint_attribute mail regex ^[[:alnum:]]$
              constraint_attribute title uri
              constraint_attribute cn,sn,givenName set
                "(this/givenName + [ ] + this/sn) & this/cn"

       A specification like the above would reject any mail attribute which
       did not look like <alpha-numeric string>  It would also
       reject any title attribute whose values were not listed in the title
       attribute of any titleCatalog entries in the given scope. (Note that
       the "dc=catalog,dc=example,dc=com" subtree ought to reside in a
       separate database, otherwise the initial set of titleCatalog entries
       could not be populated while the constraint is in effect.)  Finally, it
       requires the values of the attribute cn to be constructed by pairing
       values of the attributes sn and givenName, separated by a space, but
       only for entries derived from the objectClass inetOrgPerson.

              default slapd configuration file

       slapd.conf(5), slapd-config(5),

       This module was written in 2005 by Neil Dunbar of Hewlett-Packard and
       subsequently extended by Howard Chu and Emmanuel Dreyfus.  OpenLDAP
       Software is developed and maintained by The OpenLDAP Project
       <>.  OpenLDAP Software is derived from the
       University of Michigan LDAP 3.3 Release.

OpenLDAP 2.4.48                   2019/07/24               SLAPO-CONSTRAINT(5)