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slapo-unique(5)

NAME

   slapo-unique - Attribute Uniqueness overlay to slapd

SYNOPSIS

   /etc/ldap/slapd.conf

DESCRIPTION

   The  Attribute  Uniqueness  overlay can be used with a backend database
   such  as  slapd-bdb(5)  to  enforce  the  uniqueness  of  some  or  all
   attributes  within a scope. This subtree defaults to all objects within
   the subtree of  the  database  for  which  the  Uniqueness  overlay  is
   configured.

   Uniqueness  is  enforced  by  searching  the subtree to ensure that the
   values of all attributes  presented  with  an  add,  modify  or  modrdn
   operation are unique within the scope.  For example, if uniqueness were
   enforced for the uid attribute, the subtree would be searched  for  any
   other  records  which  also  have  a  uid attribute containing the same
   value. If any are found, the request is rejected.

   The search is performed using the rootdn  of  the  database,  to  avoid
   issues with ACLs preventing the overlay from seeing all of the relevant
   data. As such, the database must have a rootdn configured.

CONFIGURATION

   These slapd.conf options apply to  the  Attribute  Uniqueness  overlay.
   They should appear after the overlay directive.

   unique_uri <[strict ][ignore ]URI[URI...]...>
          Configure the base, attributes, scope, and filter for uniqueness
          checking.  Multiple URIs  may  be  specified  within  a  domain,
          allowing  complex  selections  of  objects.  Multiple unique_uri
          statements or olcUniqueURI attributes  will  create  independent
          domains,  each  with  their  own  independent  lists of URIs and
          ignore/strict settings.

          Keywords strict and ignore have to be  enclosed  in  quotes  (")
          together with the URI.

          The LDAP URI syntax is a subset of RFC-4516, and takes the form:

          ldap:///[base dn]?[attributes...]?scope[?filter]

          The   base  dn  defaults  to  that  of  the  back-end  database.
          Specified base dns must be within the subtree  of  the  back-end
          database.

          If  no  attributes  are  specified,  the URI applies to all non-
          operational attributes.

          The scope component is effectively mandatory, because LDAP  URIs
          default  to  base  scope,  which  is  not  valid for uniqueness,
          because groups of one object are always unique.  Scopes  of  sub
          (for subtree) and one for one-level are valid.

          The  filter  component  causes  the  domain  to apply uniqueness
          constraints     only     to     matching     objects.       e.g.
          ldap:///?cn?sub?(sn=e*)  would  require unique cn attributes for
          all objects in the subtree of the  back-end  database  whose  sn
          starts with an e.

          It  is  possible  to  assert uniqueness upon all non-operational
          attributes except those listed by prepending the keyword  ignore
          If not configured, all non-operational (e.g., system) attributes
          must be unique. Note that the attributes list of an  ignore  URI
          should   generally   contain  the  objectClass,  dc,  ou  and  o
          attributes, as these will generally not be unique, nor are  they
          operational attributes.

          It  is possible to set strict checking for the uniqueness domain
          by prepending the keyword strict.  By default, uniqueness is not
          enforced  for  null  values.  Enabling  strict  mode extends the
          concept of uniqueness to include null values, such that only one
          attribute within a subtree will be allowed to have a null value.
          Strictness applies to all URIs within a uniqueness  domain,  but
          some domains may be strict while others are not.

   It   is   not  possible  to  set  both  URIs  and  legacy  slapo-unique
   configuration  parameters  simultaneously.  In  general,   the   legacy
   configuration  options  control  pieces  of a single unfiltered subtree
   domain.

   unique_base <basedn>
          This legacy configuration parameter should be converted  to  the
          base dn component of the above unique_uri style of parameter.

   unique_ignore <attribute...>
          This  legacy  configuration  parameter  should be converted to a
          unique_uri parameter with ignore keyword as described above.

   unique_attributes <attribute...>
          This legacy configuration parameter should  be  converted  to  a
          unique_uri parameter, as described above.

   unique_strict <attribute...>
          This  legacy  configuration  parameter  should be converted to a
          strict keyword prepended to a unique_uri parameter, as described
          above.

CAVEATS

   unique_uri cannot be used with the old-style of configuration, and vice
   versa.  unique_uri can implement everything the older  system  can  do,
   however.

   Typical  attributes  for the ignore ldap:///...  URIs are intentionally
   not hardcoded into the overlay to  allow  for  maximum  flexibility  in
   meeting site-specific requirements.

   Replication  and  operations  with  manageDsaIt  control are allowed to
   bypass this enforcement. It is therefore  important  that  all  servers
   accepting  writes  have  this  overlay  configured in order to maintain
   uniqueness in a replicated DIT.

FILES

   /etc/ldap/slapd.conf
          default slapd configuration file

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