slapd-sql

title: slapd-sql(5)

summary: SQL backend to slapd

text:
# slapd-sql(5)

## NAME
slapd-sql - SQL backend to slapd

## SYNOPSIS
/etc/openldap/slapd.conf

## DESCRIPTION
The primary purpose of this slapd(8) backend is to PRESENT information stored in some RDBMS as an LDAP subtree without any programming (some SQL and maybe stored procedures can't be considered programming, anyway ;).

That is, for example, when you (some ISP) have account information you use in an RDBMS, and want to use modern solutions that expect such information in LDAP (to authenticate users, make email lookups etc.). Or you want to synchronize or distribute information between different sites/applications that use RDBMSes and/or LDAP. Or whatever else...

It is NOT designed as a general-purpose backend that uses RDBMS instead of LMDB (as the standard MDB backend does), though it can be used as such with several limitations. You can take a look at http://www.openldap.org/faq/index.cgi?file=378 (OpenLDAP FAQ-O-Matic/General LDAP FAQ/Directories vs. conventional databases) to find out more on this point.

The idea (detailed below) is to use some meta-information to translate LDAP queries to SQL queries, leaving relational schema untouched, so that old applications can continue using it without any modifications. This allows SQL and LDAP applications to inter-operate without replication, and exchange data as needed.

The SQL backend is designed to be tunable to virtually any relational schema without having to change source (through that meta-information mentioned). Also, it uses ODBC to connect to RDBMSes, and is highly configurable for SQL dialects RDBMSes may use, so it may be used for integration and distribution of data on different RDBMSes, OSes, hosts etc., in other words, in highly heterogeneous environment.

This backend is experimental.

## CONFIGURATION
These slapd.conf options apply to the SQL backend database, which means that they must follow a "database sql" line and come before any subsequent "backend" or "database" lines. Other database options not specific to this backend are described in the slapd.conf(5) manual page.

## DATA SOURCE CONFIGURATION
dbname <datasource name>

The name of the ODBC datasource to use.

dbhost <hostname>

dbpasswd <password>

dbuser <username>

The three above options are generally unneeded, because this information is taken from the datasource specified by the dbname directive. They allow to override datasource settings. Also, several RDBMS' drivers tend to require explicit passing of user/password, even if those are given in datasource (Note: dbhost is currently ignored).

## SCOPING CONFIGURATION
These options specify SQL query templates for scoping searches.

subtree_cond <SQL expression>

Specifies a where-clause template used to form a subtree search condition (dn="(.+,)?<dn>$"). It may differ from one SQL dialect to another (see samples). By default, it is constructed based on the knowledge about how to normalize DN values (e.g. "<upper_func>(ldap_entries.dn) LIKE CONCAT('%',?)"); see upper_func, upper_needs_cast, concat_pattern and strcast_func in "HELPER CONFIGURATION" for details.

children_cond <SQL expression>

Specifies a where-clause template used to form a children search condition (dn=".+,<dn>$"). It may differ from one SQL dialect to another (see samples). By default, it is constructed based on the knowledge about how to normalize DN values (e.g. "<upper_func>(ldap_entries.dn) LIKE CONCAT('%,',?)"); see upper_func, upper_needs_cast, concat_pattern and strcast_func in "HELPER CONFIGURATION" for details.

use_subtree_shortcut { YES | no }

Do not use the subtree condition when the searchBase is the database suffix, and the scope is subtree; rather collect all entries.

## STATEMENT CONFIGURATION
These options specify SQL query templates for loading schema mapping meta-information, adding and deleting entries to ldap_entries, etc. All these and subtree_cond should have the given default values. For the current value it is recommended to look at the sources, or in the log output when slapd starts with "-d 5" or greater. Note that the parameter number and order must not be changed.

oc_query <SQL expression>

The query that is used to collect the objectClass mapping data from table ldap_oc_mappings; see "METAINFORMATION USED" for details. The default is "SELECT id, name, keytbl, keycol, create_proc, delete_proc, expect_return FROM ldap_oc_mappings".

at_query <SQL expression>

The query that is used to collect the attributeType mapping data from table ldap_attr_mappings; see "METAINFORMATION USED" for details. The default is "SELECT name, sel_expr, from_tbls, join_where, add_proc, delete_proc, param_order, expect_return FROM ldap_attr_mappings WHERE oc_map_id=?".

id_query <SQL expression>

The query that is used to map a DN to an entry in table ldap_entries; see "METAINFORMATION USED" for details. The default is "SELECT id,keyval,oc_map_id,dn FROM ldap_entries WHERE <DN match expr>", where <DN match expr> is constructed based on the knowledge about how to normalize DN values (e.g. "dn=?" if no means to uppercase strings are available; typically, "<upper_func>(dn)=?" is used); see upper_func, upper_needs_cast, concat_pattern and strcast_func in "HELPER CONFIGURATION" for details.

insentry_stmt <SQL expression>

The statement that is used to insert a new entry in table ldap_entries; see "METAINFORMATION USED" for details. The default is "INSERT INTO ldap_entries (dn, oc_map_id, parent, keyval) VALUES (?, ?, ?, ?)".

delentry_stmt <SQL expression>

The statement that is used to delete an existing entry from table ldap_entries; see "METAINFORMATION USED" for details. The default is "DELETE FROM ldap_entries WHERE id=?".

delobjclasses_stmt <SQL expression>

The statement that is used to delete an existing entry's ID from table ldap_objclasses; see "METAINFORMATION USED" for details. The default is "DELETE FROM ldap_entry_objclasses WHERE entry_id=?".

## HELPER CONFIGURATION
These statements are used to modify the default behavior of the backend according to issues of the dialect of the RDBMS. The first options essentially refer to string and DN normalization when building filters. LDAP normalization is more than upper- (or lower-)casing everything; however, as a reasonable trade-off, for case-sensitive RDBMSes the backend can be instructed to uppercase strings and DNs by providing the upper_func directive. Some RDBMSes, to use functions on arbitrary data types, e.g. string constants, requires a cast, which is triggered by the upper_needs_cast directive. If required, a string cast function can be provided as well, by using the strcast_func directive. Finally, a custom string concatenation pattern may be required; it is provided by the concat_pattern directive.

upper_func <SQL function name>

Specifies the name of a function that converts a given value to uppercase. This is used for case insensitive matching when the RDBMS is case sensitive. It may differ from one SQL dialect to another (e.g. UCASE, UPPER or whatever; see samples). By default, none is used, i.e. strings are not uppercased, so matches may be case sensitive.

upper_needs_cast { NO | yes }

Set this directive to yes if upper_func needs an explicit cast when applied to literal strings. A cast in the form CAST (<arg> AS VARCHAR(<max DN length>)) is used, where <max DN length> is builtin in back-sql; see macro BACKSQL_MAX_DN_LEN (currently 255; note that slapd's builtin limit, in macro SLAP_LDAPDN_MAXLEN, is set to 8192). This is experimental and may change in future releases.

strcast_func <SQL function name>

Specifies the name of a function that converts a given value to a string for appropriate ordering. This is used in "SELECT DISTINCT" statements for strongly typed RDBMSes with little implicit casting (like PostgreSQL), when a literal string is specified. This is experimental and may change in future releases.

concat_pattern <pattern>

This statement defines the pattern that is used to concatenate strings. The pattern MUST contain two question marks, '?', that will be replaced by the two strings that must be concatenated. The default value is CONCAT(?,?); a form that is known to be highly portable (IBM db2, PostgreSQL) is ?||?, but an explicit cast may be required when operating on literal strings: CAST(?||? AS VARCHAR(<length>)). On some RDBMSes (IBM db2, MSSQL) the form ?+? is known to work as well. Carefully check the documentation of your RDBMS or stay with the examples for supported ones. This is experimental and may change in future releases.

aliasing_keyword <string>

Define the aliasing keyword. Some RDBMSes use the word "AS" (the default), others don't use any.

aliasing_quote <string>

Define the quoting char of the aliasing keyword. Some RDBMSes don't require any (the default), others may require single or double quotes.

has_ldapinfo_dn_ru { NO | yes }

Explicitly inform the backend whether the dn_ru column (DN in reverse uppercased form) is present in table ldap_entries. Overrides automatic check (this is required, for instance, by PostgreSQL/unixODBC). This is experimental and may change in future releases.

fail_if_no_mapping { NO | yes }

When set to yes it forces attribute write operations to fail if no appropriate mapping between LDAP attributes and SQL data is available. The default behavior is to ignore those changes that cannot be mapped. It has no impact on objectClass mapping, i.e. if the structuralObjectClass of an entry cannot be mapped to SQL by looking up its name in ldap_oc_mappings, an add operation will fail regardless of the fail_if_no_mapping switch; see section "METAINFORMATION USED" for details. This is experimental and may change in future releases.

allow_orphans { NO | yes }

When set to yes orphaned entries (i.e. without the parent entry in the database) can be added. This option should be used with care, possibly in conjunction with some special rule on the RDBMS side that dynamically creates the missing parent.

baseObject [ <filename> ]

Instructs the database to create and manage an in-memory baseObject entry instead of looking for one in the RDBMS. If the (optional) <filename> argument is given, the entry is read from that file in LDIF(5) format; otherwise, an entry with objectClass extensibleObject is created based on the contents of the RDN of the baseObject. This is particularly useful when ldap_entries information is stored in a view rather than in a table, and union is not supported for views, so that the view can only specify one rule to compute the entry structure for one objectClass. This topic is discussed further in section "METAINFORMATION USED". This is experimental and may change in future releases.

create_needs_select { NO | yes }

Instructs the database whether or not entry creation in table ldap_entries needs a subsequent select to collect the automatically assigned ID, instead of being returned by a stored procedure.

fetch_attrs <attrlist>

fetch_all_attrs { NO | yes }

The first statement allows one to provide a list of attributes that must always be fetched in addition to those requested by any specific operation, because they are required for the proper usage of the backend. For instance, all attributes used in ACLs should be listed here. The second statement is a shortcut to require all attributes to be always loaded. Note that the dynamically generated attributes, e.g. hasSubordinates, entryDN and other implementation dependent attributes are NOT generated at this point, for consistency with the rest of slapd. This may change in the future.

check_schema { YES | no }

Instructs the database to check schema adherence of entries after modifications, and structural objectClass chain when entries are built. By default it is set to yes.

sqllayer <name> [...]

Loads the layer <name> onto a stack of helpers that are used to map DNs from LDAP to SQL representation and vice-versa. Subsequent args are passed to the layer configuration routine. This is highly experimental and should be used with extreme care. The API of the layers is not frozen yet, so it is unpublished.

autocommit { NO | yes }

Activates autocommit; by default, it is off.

## METAINFORMATION USED
Almost everything mentioned later is illustrated in examples located in the servers/slapd/back-sql/rdbms_depend/ directory in the OpenLDAP source tree, and contains scripts for generating sample database for Oracle, MS SQL Server, mySQL and more (including PostgreSQL and IBM db2).

The first thing that one must arrange is what set of LDAP object classes can present your RDBMS information.

The easiest way is to create an objectClass for each entity you had in ER-diagram when designing your relational schema. Any relational schema, no matter how normalized it is, was designed after some model of your application's domain (for instance, accounts, services etc. in ISP), and is used in terms of its entities, not just tables of normalized schema. It means that for every attribute of every such instance there is an effective SQL query that loads its values.

Also you might want your object classes to conform to some of the standard schemas like inetOrgPerson etc.

Nevertheless, when you think it out, we must define a way to translate LDAP operation requests to (a series of) SQL queries. Let us deal with the SEARCH operation.

Example: Let's suppose that we store information about persons working in our organization in two tables:

```
  PERSONS              PHONES

  ----------           -------------

  id integer           id integer

  first_name varchar   pers_id integer references persons(id)

  last_name varchar    phone

  middle_name varchar

  ...
```

(PHONES contains telephone numbers associated with persons). A person can have several numbers, then PHONES contains several records with corresponding pers_id, or no numbers (and no records in PHONES with such pers_id). An LDAP objectclass to present such information could look like this:

```
  person

  -------

  MUST cn

  MAY telephoneNumber $ firstName $ lastName

  ...
```

To fetch all values for cn attribute given person ID, we construct the query:

```
  SELECT CONCAT(persons.first_name,' ',persons.last_name)

      AS cn FROM persons WHERE persons.id=?
```

for telephoneNumber we can use:

```
  SELECT phones.phone AS telephoneNumber FROM persons,phones

      WHERE persons.id=phones.pers_id AND persons.id=?
```

If we wanted to service LDAP requests with filters like (telephoneNumber=123*), we would construct something like:

```
  SELECT ... FROM persons,phones

      WHERE persons.id=phones.pers_id

          AND persons.id=?

          AND phones.phone like '%1%2%3%'
```

(note how the telephoneNumber match is expanded in multiple wildcards to account for interspersed ininfluential chars like spaces, dashes and so; this occurs by design because telephoneNumber is defined after a specially recognized syntax). So, if we had information about what tables contain values for each attribute, how to join these tables and arrange these values, we could try to automatically generate such statements, and translate search filters to SQL WHERE clauses.

To store such information, we add three more tables to our schema and fill it with data (see samples):

```
  ldap_oc_mappings (some columns are not listed for clarity)

  ---------------

  id=1

  name="person"

  keytbl="persons"

  keycol="id"
```

This table defines a mapping between objectclass (its name held in the "name" column), and a table that holds the primary key for corresponding entities. For instance, in our example, the person entity, which we are trying to present as "person" objectclass, resides in two tables (persons and phones), and is identified by the persons.id column (that we will call the primary key for this entity). Keytbl and keycol thus contain "persons" (name of the table), and "id" (name of the column).

```
  ldap_attr_mappings (some columns are not listed for clarity)

  -----------

  id=1

  oc_map_id=1

  name="cn"

  sel_expr="CONCAT(persons.first_name,' ',persons.last_name)"

  from_tbls="persons"

  join_where=NULL

  ************

  id=<n>

  oc_map_id=1

  name="telephoneNumber"

  sel_expr="phones.phone"

  from_tbls="persons,phones"

  join_where="phones.pers_id=persons.id"
```

This table defines mappings between LDAP attributes and SQL queries that load their values. Note that, unlike LDAP schema, these are not attribute types - the attribute "cn" for "person" objectclass can have its values in different tables than "cn" for some other objectclass, so attribute mappings depend on objectclass mappings (unlike attribute types in LDAP schema, which are indifferent to objectclasses). Thus, we have oc_map_id column with link to oc_mappings table.

Now we cut the SQL query that loads values for a given attribute into 3 parts. First goes into sel_expr column - this is the expression we had between SELECT and FROM keywords, which defines WHAT to load. Next is table list - text between FROM and WHERE keywords. It may contain aliases for convenience (see examples). The last is part of the where clause, which (if it exists at all) expresses the condition for joining the table containing values with the table containing the primary key (foreign key equality and such). If values are in the same table as the primary key, then this column is left NULL (as for cn attribute above).

Having this information in parts, we are able to not only construct queries that load attribute values by id of entry (for this we could store SQL query as a whole), but to construct queries that load id's of objects that correspond to a given search filter (or at least part of it). See below for examples.

```
  ldap_entries

  ------------

  id=1

  dn=<dn you choose>

  oc_map_id=...

  parent=<parent record id>

  keyval=<value of primary key>
```

This table defines mappings between DNs of entries in your LDAP tree, and values of primary keys for corresponding relational data. It has recursive structure (parent column references id column of the same table), which allows you to add any tree structure(s) to your flat relational data. Having id of objectclass mapping, we can determine table and column for primary key, and keyval stores value of it, thus defining the exact tuple corresponding to the LDAP entry with this DN.

Note that such design (see exact SQL table creation query) implies one important constraint - the key must be an integer. But all that I know about well-designed schemas makes me think that it's not very narrow ;) If anyone needs support for different types for keys - he may want to write a patch, and submit it to OpenLDAP ITS, then I'll include it.

Also, several users complained that they don't really need very structured trees, and they don't want to update one more table every time they add or delete an instance in the relational schema. Those people can use a view instead of a real table for ldap_entries, something like this (by Robin Elfrink):

```
  CREATE VIEW ldap_entries (id, dn, oc_map_id, parent, keyval)

      AS

          SELECT 0, UPPER('o=MyCompany,c=NL'),

              3, 0, 'baseObject' FROM unixusers WHERE userid='root'

      UNION

          SELECT (1000000000+userid),

              UPPER(CONCAT(CONCAT('cn=',gecos),',o=MyCompany,c=NL')),

              1, 0, userid FROM unixusers

      UNION

          SELECT (2000000000+groupnummer),

              UPPER(CONCAT(CONCAT('cn=',groupname),',o=MyCompany,c=NL')),

              2, 0, groupnummer FROM groups;
```

If your RDBMS does not support unions in views, only one objectClass can be mapped in ldap_entries, and the baseObject cannot be created; in this case, see the baseObject directive for a possible workaround.

## TYPICAL SQL BACKEND OPERATION
Having meta-information loaded, the SQL backend uses these tables to determine a set of primary keys of candidates (depending on search scope and filter). It tries to do it for each objectclass registered in ldap_objclasses.

Example: for our query with filter (telephoneNumber=123*) we would get the following query generated (which loads candidate IDs)

```
  SELECT ldap_entries.id,persons.id, 'person' AS objectClass,

         ldap_entries.dn AS dn

    FROM ldap_entries,persons,phones

   WHERE persons.id=ldap_entries.keyval

     AND ldap_entries.objclass=?

     AND ldap_entries.parent=?

     AND phones.pers_id=persons.id

     AND (phones.phone LIKE '%1%2%3%')
```

(for ONELEVEL search) or "... AND dn=?" (for BASE search) or "... AND dn LIKE '%?'" (for SUBTREE)

Then, for each candidate, we load the requested attributes using per-attribute queries like

```
  SELECT phones.phone AS telephoneNumber

    FROM persons,phones

   WHERE persons.id=? AND phones.pers_id=persons.id
```

Then, we use test_filter() from the frontend API to test the entry for a full LDAP search filter match (since we cannot effectively make sense of SYNTAX of corresponding LDAP schema attribute, we translate the filter into the most relaxed SQL condition to filter candidates), and send it to the user.

ADD, DELETE, MODIFY and MODRDN operations are also performed on per-attribute meta-information (add_proc etc.). In those fields one can specify an SQL statement or stored procedure call which can add, or delete given values of a given attribute, using the given entry keyval (see examples -- mostly PostgreSQL, ORACLE and MSSQL - since as of this writing there are no stored procs in MySQL).

We just add more columns to ldap_oc_mappings and ldap_attr_mappings, holding statements to execute (like create_proc, add_proc, del_proc etc.), and flags governing the order of parameters passed to those statements. Please see samples to find out what are the parameters passed, and other information on this matter - they are self-explanatory for those familiar with the concepts expressed above.

## COMMON TECHNIQUES
First of all, let's recall that among other major differences to the complete LDAP data model, the above illustrated concept does not directly support such features as multiple objectclasses per entry, and referrals. Fortunately, they are easy to adopt in this scheme. The SQL backend requires that one more table is added to the schema: ldap_entry_objectclasses(entry_id,oc_name).

That table contains any number of objectclass names that corresponding entries will possess, in addition to that mentioned in mapping. The SQL backend automatically adds attribute mapping for the "objectclass" attribute to each objectclass mapping that loads values from this table. So, you may, for instance, have a mapping for inetOrgPerson, and use it for queries for "person" objectclass...

Referrals used to be implemented in a loose manner by adding an extra table that allowed any entry to host a "ref" attribute, along with a "referral" extra objectClass in table ldap_entry_objclasses. In the current implementation, referrals are treated like any other user-defined schema, since "referral" is a structural objectclass. The suggested practice is to define a "referral" entry in ldap_oc_mappings, holding a naming attribute, e.g. "ou" or "cn", a "ref" attribute, containing the url; in case multiple referrals per entry are needed, a separate table for urls can be created, where urls are mapped to the respective entries. The use of the naming attribute usually requires to add an "extensibleObject" value to ldap_entry_objclasses.

## CAVEATS
As previously stated, this backend should not be considered a replacement of other data storage backends, but rather a gateway to existing RDBMS storages that need to be published in LDAP form.

The hasSubordinates operational attribute is honored by back-sql in search results and in compare operations; it is partially honored also in filtering. Owing to design limitations, a (brain-dead?) filter of the form (!(hasSubordinates=TRUE)) will give no results instead of returning all the leaf entries, because it actually expands into ... AND NOT (1=1). If you need to find all the leaf entries, please use (hasSubordinates=FALSE) instead.

A directoryString value of the form "__First___Last_" (where underscores mean spaces, ASCII 0x20 char) corresponds to its prettified counterpart "First_Last"; this is not currently honored by back-sql if non-prettified data is written via RDBMS; when non-prettified data is written through back-sql, the prettified values are actually used instead.

## BUGS
When the ldap_entry_objclasses table is empty, filters on the objectClass attribute erroneously result in no candidates. A workaround consists in adding at least one row to that table, no matter if valid or not.

## PROXY CACHE OVERLAY
The proxy cache overlay allows caching of LDAP search requests (queries) in a local database. See slapo-pcache(5) for details.

## EXAMPLES
There are example SQL modules in the slapd/back-sql/rdbms_depend/ directory in the OpenLDAP source tree.

## ACCESS CONTROL
The sql backend honors access control semantics as indicated in slapd.access(5) (including the disclose access privilege when enabled at compile time).

## FILES
/etc/openldap/slapd.conf

default slapd configuration file

## SEE ALSO
slapd.conf(5), slapd(8).


slapd-wt

package: openldap-servers

title: slapd-wt(5)

summary: WiredTiger backend to slapd

text:
# slapd-wt(5)

## NAME
slapd-wt - WiredTiger backend to slapd

## SYNOPSIS
/etc/openldap/slapd.conf

## DESCRIPTION
The wt backend to slapd(8) uses WiredTiger database library to store data.

The wt backend is experimental module that have potential high write performance and high concurrency performance. This backend have not some basic feature yet. Please backup data using slapcat before update the module.

## CONFIGURATION
These slapd.conf options apply to the wt backend database. That is, they must follow a "database wt" line and come before any subsequent "backend" or "database" lines. Other database options are described in the slapd.conf(5) manual page.

directory <directory>

Specify WiredTiger home directory that containing this database and associated indexes live. A separate directory must be specified for each database. The default is /var/lib/openldap-data.

idlcache <boolean>

Use the in-memory idlcache. The default is true.

index {<attrlist>|default} [pres,eq,approx,sub,<special>]

Specify the indexes to maintain for the given attribute (or list of attributes). Some attributes only support a subset of indexes. If only an <attr> is given, the indices specified for default are maintained. Note that setting a default does not imply that all attributes will be indexed. Also, for best performance, an eq index should always be configured for the objectClass attribute.

mode <integer>

back-wt does not support mode option. use umask instead.

wtconfig {create,cache_size=512M,async=(enabled)}

Specify configuration for wiredtiger, This parameter is pass to wiredtiger_open(3).

create

create the database if it does not exist.

cache_size

maximum heap memory to allocate for the cache.

async

asynchronous operations configuration options. disabled by default.

## ACCESS CONTROL
The wt backend honors access control semantics as indicated in slapd.access(5).

## FILES
/etc/openldap/slapd.conf

default slapd configuration file

## SEE ALSO
slapd.conf(5), slapd-config(5), slapd(8), slapadd(8), slapcat(8), slapindex(8), slapmodify(8), WiredTiger documentation.

## ACKNOWLEDGEMENTS
OpenLDAP Software is developed and maintained by The OpenLDAP Project <http://www.openldap.org/>. OpenLDAP Software is derived from the University of Michigan LDAP 3.3 Release. Written by HAMANO Tsukasa <hamano@osstech.co.jp>.

branch: sisyphus


slapd.access

title: slapd.access(5)

text:
# slapd.access(5)

## NAME
slapd.access - access configuration for slapd, the stand-alone LDAP daemon

## SYNOPSIS
/etc/openldap/slapd.conf

## DESCRIPTION
The slapd.conf(5) file contains configuration information for the slapd(8) daemon. This configuration file is also used by the SLAPD tools slapacl(8), slapadd(8), slapauth(8), slapcat(8), slapdn(8), slapindex(8), slapmodify(8), and slaptest(8).

The slapd.conf file consists of a series of global configuration options that apply to slapd as a whole (including all backends), followed by zero or more database backend definitions that contain information specific to a backend instance.

The general format of slapd.conf is as follows:

```
    # comment - these options apply to every database

    <global configuration options>

    # first database definition & configuration options

    database    <backend 1 type>

    <configuration options specific to backend 1>

    # subsequent database definitions & configuration options

    ...
```

Both the global configuration and each backend-specific section can contain access information. Backend-specific access control directives are used for those entries that belong to the backend, according to their naming context. In case no access control directives are defined for a backend or those which are defined are not applicable, the directives from the global configuration section are then used.

If no access controls are present, the default policy allows anyone and everyone to read anything but restricts updates to rootdn. (e.g., "access to * by * read").

When dealing with an access list, because the global access list is effectively appended to each per-database list, if the resulting list is non-empty then the access list will end with an implicit access to * by * none directive. If there are no access directives applicable to a backend, then a default read is used.

Be warned: the rootdn can always read and write EVERYTHING!

For entries not held in any backend (such as a root DSE), the global directives are used.

Arguments that should be replaced by actual text are shown in brackets <>.

## THE ACCESS DIRECTIVE
The structure of the access control directives is

access to <what> [ by <who> [ <access> ] [ <control> ] ]+

Grant access (specified by <access>) to a set of entries and/or attributes (specified by <what>) by one or more requestors (specified by <who>).

Lists of access directives are evaluated in the order they appear in slapd.conf. When a <what> clause matches the datum whose access is being evaluated, its <who> clause list is checked. When a <who> clause matches the accessor's properties, its <access> and <control> clauses are evaluated.

Access control checking stops at the first match of the <what> and <who> clause, unless otherwise dictated by the <control> clause. Each <who> clause list is implicitly terminated by a

```
	by * none stop
```

<control> clause. This implicit <control> stops access directive evaluation with no more access privileges granted to anyone else. To stop access directive evaluation only when both <who> and <what> match, add an explicit

```
	by * break
```

to the end of the <who> clause list.

Each <what> clause list is implicitly terminated by a

```
	access to *
		by * none
```

clause that results in granting no access privileges to an otherwise unspecified datum.

## THE <WHAT> FIELD
The field <what> specifies the entity the access control directive applies to. It can have the forms

```
	dn[.<dnstyle>]=<dnpattern>
	filter=<ldapfilter>
	attrs=<attrlist>[ val[/matchingRule][.<attrstyle>]=<attrval>]
```

with

```
	<dnstyle>={{exact|base(object)}|regex
		|one(level)|sub(tree)|children}
	<attrlist>={<attr>|[{!|@}]<objectClass>}[,<attrlist>]
	<attrstyle>={{exact|base(object)}|regex
		|one(level)|sub(tree)|children}
```

The statement dn=<dnpattern> selects the entries based on their naming context. The <dnpattern> is a string representation of the entry's DN. The wildcard * stands for all the entries, and it is implied if no dn form is given.

The <dnstyle> is optional; however, it is recommended to specify it to avoid ambiguities. Base (synonym of baseObject), the default, or exact (an alias of base) indicates the entry whose DN is equal to the <dnpattern>; one (synonym of onelevel) indicates all the entries immediately below the <dnpattern>, sub (synonym of subtree) indicates all entries in the subtree at the <dnpattern>, children indicates all the entries below (subordinate to) the <dnpattern>.

If the <dnstyle> qualifier is regex, then <dnpattern> is a POSIX (''extended'') regular expression pattern, as detailed in regex(7) and/or re_format(7), matching a normalized string representation of the entry's DN. The regex form of the pattern does not (yet) support UTF-8.

The statement filter=<ldapfilter> selects the entries based on a valid LDAP filter as described in RFC 4515. A filter of (objectClass=*) is implied if no filter form is given.

The statement attrs=<attrlist> selects the attributes the access control rule applies to. It is a comma-separated list of attribute types, plus the special names entry, indicating access to the entry itself, and children, indicating access to the entry's children. ObjectClass names may also be specified in this list, which will affect all the attributes that are required and/or allowed by that objectClass. Actually, names in <attrlist> that are prefixed by @ are directly treated as objectClass names. A name prefixed by ! is also treated as an objectClass, but in this case the access rule affects the attributes that are not required nor allowed by that objectClass. If no attrs form is given, attrs=@extensibleObject is implied, i.e. all attributes are addressed.

Using the form attrs=<attr> val[/matchingRule][.<attrstyle>]=<attrval> specifies access to a particular value of a single attribute. In this case, only a single attribute type may be given. The <attrstyle> exact (the default) uses the attribute's equality matching rule to compare the value, unless a different (and compatible) matching rule is specified. If the <attrstyle> is regex, the provided value is used as a POSIX (''extended'') regular expression pattern. If the attribute has DN syntax, the <attrstyle> can be any of base, onelevel, subtree or children, resulting in base, onelevel, subtree or children match, respectively.

The dn, filter, and attrs statements are additive; they can be used in sequence to select entities the access rule applies to based on naming context, value and attribute type simultaneously. Submatches resulting from regex matching can be dereferenced in the <who> field using the syntax ${v<n>}, where <n> is the submatch number. The default syntax, $<n>, is actually an alias for ${d<n>}, that corresponds to dereferencing submatches from the dnpattern portion of the <what> field.

## THE <WHO> FIELD
The field <who> indicates whom the access rules apply to. Multiple <who> statements can appear in an access control statement, indicating the different access privileges to the same resource that apply to different accessee. It can have the forms

```
	*
	anonymous
	users
	self[.<selfstyle>]
	dn[.<dnstyle>[,<modifier>]]=<DN>
	dnattr=<attrname>
	realanonymous
	realusers
	realself[.<selfstyle>]
	realdn[.<dnstyle>[,<modifier>]]=<DN>
	realdnattr=<attrname>
	group[/<objectclass>[/<attrname>]]
		[.<groupstyle>]=<group>
	peername[.<peernamestyle>]=<peername>
	sockname[.<style>]=<sockname>
	domain[.<domainstyle>[,<modifier>]]=<domain>
	sockurl[.<style>]=<sockurl>
	set[.<setstyle>]=<pattern>
	ssf=<n>
	transport_ssf=<n>
	tls_ssf=<n>
	sasl_ssf=<n>
	dynacl/<name>[/<options>][.<dynstyle>][=<pattern>]
```

with

```
	<style>={exact|regex|expand}
	<selfstyle>={level{<n>}}
	<dnstyle>={{exact|base(object)}|regex
		|one(level)|sub(tree)|children|level{<n>}}
	<groupstyle>={exact|expand}
	<peernamestyle>={<style>|ip|ipv6|path}
	<domainstyle>={exact|regex|sub(tree)}
	<setstyle>={exact|expand}
	<modifier>={expand}
	<name>=aci		<pattern>=<attrname>]
```

They may be specified in combination.

```

```

The wildcard * refers to everybody.

The keywords prefixed by real act as their counterparts without prefix; the checking respectively occurs with the authentication DN and the authorization DN.

The keyword anonymous means access is granted to unauthenticated clients; it is mostly used to limit access to authentication resources (e.g. the userPassword attribute) to unauthenticated clients for authentication purposes.

The keyword users means access is granted to authenticated clients.

The keyword self means access to an entry is allowed to the entry itself (e.g. the entry being accessed and the requesting entry must be the same). It allows the level{<n>} style, where <n> indicates what ancestor of the DN is to be used in matches. A positive value indicates that the <n>-th ancestor of the user's DN is to be considered; a negative value indicates that the <n>-th ancestor of the target is to be considered. For example, a "by self.level{1} ..." clause would match when the object "dc=example,dc=com" is accessed by "cn=User,dc=example,dc=com". A "by self.level{-1} ..." clause would match when the same user accesses the object "ou=Address Book,cn=User,dc=example,dc=com".

The statement dn=<DN> means that access is granted to the matching DN. The optional style qualifier dnstyle allows the same choices of the dn form of the <what> field. In addition, the regex style can exploit substring substitution of submatches in the <what> dn.regex clause by using the form $<digit>, with digit ranging from 0 to 9 (where 0 matches the entire string), or the form ${<digit>+}, for submatches higher than 9. Substring substitution from attribute value can be done in using the form ${v<digit>+}. Since the dollar character is used to indicate a substring replacement, the dollar character that is used to indicate match up to the end of the string must be escaped by a second dollar character, e.g.

```
    access to dn.regex="^(.+,)?uid=([^,]+),dc=[^,]+,dc=com$"

        by dn.regex="^uid=$2,dc=[^,]+,dc=com$$" write
```

The style qualifier allows an optional modifier. At present, the only type allowed is expand, which causes substring substitution of submatches to take place even if dnstyle is not regex. Note that the regex dnstyle in the above example may be of use only if the <by> clause needs to be a regex; otherwise, if the value of the second (from the right) dc= portion of the DN in the above example were fixed, the form

```
    access to dn.regex="^(.+,)?uid=([^,]+),dc=example,dc=com$"

        by dn.exact,expand="uid=$2,dc=example,dc=com" write
```

could be used; if it had to match the value in the <what> clause, the form

```
    access to dn.regex="^(.+,)?uid=([^,]+),dc=([^,]+),dc=com$"

        by dn.exact,expand="uid=$2,dc=$3,dc=com" write
```

could be used.

Forms of the <what> clause other than regex may provide submatches as well. The base(object), the sub(tree), the one(level), and the children forms provide $0 as the match of the entire string. The sub(tree), the one(level), and the children forms also provide $1 as the match of the rightmost part of the DN as defined in the <what> clause. This may be useful, for instance, to provide access to all the ancestors of a user by defining

```
    access to dn.subtree="dc=com"

        by dn.subtree,expand="$1" read
```

which means that only access to entries that appear in the DN of the <by> clause is allowed.

The level{<n>} form is an extension and a generalization of the onelevel form, which matches all DNs whose <n>-th ancestor is the pattern. So, level{1} is equivalent to onelevel, and level{0} is equivalent to base.

It is perfectly useless to give any access privileges to a DN that exactly matches the rootdn of the database the ACLs apply to, because it implicitly possesses write privileges for the entire tree of that database. Actually, access control is bypassed for the rootdn, to solve the intrinsic chicken-and-egg problem.

The statement dnattr=<attrname> means that access is granted to requests whose DN is listed in the entry being accessed under the <attrname> attribute.

The statement group=<group> means that access is granted to requests whose DN is listed in the group entry whose DN is given by <group>. The optional parameters <objectclass> and <attrname> define the objectClass and the member attributeType of the group entry. The defaults are groupOfNames and member, respectively. The optional style qualifier <style> can be expand, which means that <group> will be expanded as a replacement string (but not as a regular expression) according to regex(7) and/or re_format(7), and exact, which means that exact match will be used. If the style of the DN portion of the <what> clause is regex, the submatches are made available according to regex(7) and/or re_format(7); other styles provide limited submatches as discussed above about the DN form of the <by> clause.

For static groups, the specified attributeType must have DistinguishedName or NameAndOptionalUID syntax. For dynamic groups the attributeType must be a subtype of the labeledURI attributeType. Only LDAP URIs of the form ldap:///<base>??<scope>?<filter> will be evaluated in a dynamic group, by searching the local server only.

The statements peername=<peername>, sockname=<sockname>, domain=<domain>, and sockurl=<sockurl> mean that the contacting host IP (in the form IP=<ip>:<port> for IPv4, or IP=[<ipv6>]:<port> for IPv6) or the contacting host named pipe file name (in the form PATH=<path> if connecting through a named pipe) for peername, the named pipe file name for sockname, the contacting host name for domain, and the contacting URL for sockurl are compared against pattern to determine access. The same style rules for pattern match described for the group case apply, plus the regex style, which implies submatch expand and regex match of the corresponding connection parameters. The exact style of the <peername> clause (the default) implies a case-exact match on the client's IP, including the IP= prefix and the trailing :<port>, or the client's path, including the PATH= prefix if connecting through a named pipe. The special ip style interprets the pattern as <peername>=<ip>[%<mask>][{<n>}], where <ip> and <mask> are dotted digit representations of the IP and the mask, while <n>, delimited by curly brackets, is an optional port. The same applies to IPv6 addresses when the special ipv6 style is used. When checking access privileges, the IP portion of the peername is extracted, eliminating the IP= prefix and the :<port> part, and it is compared against the <ip> portion of the pattern after masking with <mask>: ((peername & <mask>) == <ip>). As an example, peername.ip=127.0.0.1 and peername.ipv6=::1 allow connections only from localhost, peername.ip=192.168.1.0%255.255.255.0 allows connections from any IP in the 192.168.1 class C domain, and peername.ip=192.168.1.16%255.255.255.240{9009} allows connections from any IP in the 192.168.1.[16-31] range of the same domain, only if port 9009 is used. The special path style eliminates the PATH= prefix from the peername when connecting through a named pipe, and performs an exact match on the given pattern. The <domain> clause also allows the subtree style, which succeeds when a fully qualified name exactly matches the domain pattern, or its trailing part, after a dot, exactly matches the domain pattern. The expand style is allowed, implying an exact match with submatch expansion; the use of expand as a style modifier is considered more appropriate. As an example, domain.subtree=example.com will match www.example.com, but will not match www.anotherexample.com. The domain of the contacting host is determined by performing a DNS reverse lookup. As this lookup can easily be spoofed, use of the domain statement is strongly discouraged. By default, reverse lookups are disabled. The optional domainstyle qualifier of the <domain> clause allows a modifier option; the only value currently supported is expand, which causes substring substitution of submatches to take place even if the domainstyle is not regex, much like the analogous usage in <dn> clause.

The statement set=<pattern> is undocumented yet.

The statement dynacl/<name>[/<options>][.<dynstyle>][=<pattern>] means that access checking is delegated to the admin-defined method indicated by <name>, which can be registered at run-time by means of the moduleload statement. The fields <options>, <dynstyle> and <pattern> are optional, and are directly passed to the registered parsing routine. Dynacl is experimental; it must be enabled at compile time.

The statement dynacl/aci[=<attrname>] means that the access control is determined by the values in the attrname of the entry itself. The optional <attrname> indicates what attributeType holds the ACI information in the entry. By default, the OpenLDAPaci operational attribute is used. ACIs are experimental; they must be enabled at compile time.

The statements ssf=<n>, transport_ssf=<n>, tls_ssf=<n>, and sasl_ssf=<n> set the minimum required Security Strength Factor (ssf) needed to grant access. The value should be positive integer.

## THE <ACCESS> FIELD
The optional field <access> ::= [[real]self]{<level>|<priv>} determines the access level or the specific access privileges the who field will have. Its component are defined as

```
	<level> ::= none|disclose|auth|compare|search|read|{write|add|delete}|manage
	<priv> ::= {=|+|-}{0|d|x|c|s|r|{w|a|z}|m}+
```

The modifier self allows special operations like having a certain access level or privilege only in case the operation involves the name of the user that's requesting the access. It implies the user that requests access is authorized. The modifier realself refers to the authenticated DN as opposed to the authorized DN of the self modifier. An example is the selfwrite access to the member attribute of a group, which allows one to add/delete its own DN from the member list of a group, while being not allowed to affect other members.

The level access model relies on an incremental interpretation of the access privileges. The possible levels are none, disclose, auth, compare, search, read, write, and manage. Each access level implies all the preceding ones, thus manage grants all access including administrative access. This access allows some modifications which would otherwise be prohibited by the LDAP data model or the directory schema, e.g. changing the structural objectclass of an entry, or modifying an operational attribute that is defined as not user modifiable. The write access is actually the combination of add and delete, which respectively restrict the write privilege to add or delete the specified <what>.

The none access level disallows all access including disclosure on error.

The disclose access level allows disclosure of information on error.

The auth access level means that one is allowed access to an attribute to perform authentication/authorization operations (e.g. bind) with no other access. This is useful to grant unauthenticated clients the least possible access level to critical resources, like passwords.

The priv access model relies on the explicit setting of access privileges for each clause. The = sign resets previously defined accesses; as a consequence, the final access privileges will be only those defined by the clause. The + and - signs add/remove access privileges to the existing ones. The privileges are m for manage, w for write, a for add, z for delete, r for read, s for search, c for compare, x for authentication, and d for disclose. More than one of the above privileges can be added in one statement. 0 indicates no privileges and is used only by itself (e.g., +0). Note that +az is equivalent to +w.

If no access is given, it defaults to +0.

## THE <CONTROL> FIELD
The optional field <control> controls the flow of access rule application. It can have the forms

```
	stop
	continue
	break
```

where stop, the default, means access checking stops in case of match. The other two forms are used to keep on processing access clauses. In detail, the continue form allows for other <who> clauses in the same <access> clause to be considered, so that they may result in incrementally altering the privileges, while the break form allows for other <access> clauses that match the same target to be processed. Consider the (silly) example

```
	access to dn.subtree="dc=example,dc=com" attrs=cn
		by * =cs break
	access to dn.subtree="ou=People,dc=example,dc=com"
		by * +r
```

which allows search and compare privileges to everybody under the "dc=example,dc=com" tree, with the second rule allowing also read in the "ou=People" subtree, or the (even more silly) example

```
	access to dn.subtree="dc=example,dc=com" attrs=cn
		by * =cs continue
		by users +r
```

which grants everybody search and compare privileges, and adds read privileges to authenticated clients.

One useful application is to easily grant write privileges to an updatedn that is different from the rootdn. In this case, since the updatedn needs write access to (almost) all data, one can use

```
	access to *
		by dn.exact="cn=The Update DN,dc=example,dc=com" write
		by * break
```

as the first access rule. As a consequence, unless the operation is performed with the updatedn identity, control is passed straight to the subsequent rules.

## OPERATION REQUIREMENTS
Operations require different privileges on different portions of entries. The following summary applies to primary MDB database backend. Requirements for other backends may (and often do) differ.

The add operation requires add (=a) privileges on the pseudo-attribute entry of the entry being added, and add (=a) privileges on the pseudo-attribute children of the entry's parent. When adding the suffix entry of a database, add access to children of the empty DN ("") is required. Also if Add content ACL checking has been configured on the database (see the slapd.conf(5) or slapd-config(5) manual page), add (=a) will be required on all of the attributes being added.

The bind operation, when credentials are stored in the directory, requires auth (=x) privileges on the attribute the credentials are stored in (usually userPassword).

The compare operation requires compare (=c) privileges on the attribute that is being compared.

The delete operation requires delete (=z) privileges on the pseudo-attribute entry of the entry being deleted, and delete (=d) privileges on the children pseudo-attribute of the entry's parent.

The modify operation requires write (=w) privileges on the attributes being modified. In detail, add (=a) is required to add new values, delete (=z) is required to delete existing values, and both delete and add (=az), or write (=w), are required to replace existing values.

The modrdn operation requires write (=w) privileges on the pseudo-attribute entry of the entry whose relative DN is being modified, delete (=z) privileges on the pseudo-attribute children of the old entry's parents, add (=a) privileges on the pseudo-attribute children of the new entry's parents, and add (=a) privileges on the attributes that are present in the new relative DN. Delete (=z) privileges are also required on the attributes that are present in the old relative DN if deleteoldrdn is set to 1.

The search operation, requires search (=s) privileges on the entry pseudo-attribute of the searchBase (NOTE: this was introduced with OpenLDAP 2.4). Then, for each entry, it requires search (=s) privileges on the attributes that are defined in the filter. The resulting entries are finally tested for read (=r) privileges on the pseudo-attribute entry (for read access to the entry itself) and for read (=r) access on each value of each attribute that is requested. Also, for each referral object used in generating continuation references, the operation requires read (=r) access on the pseudo-attribute entry (for read access to the referral object itself), as well as read (=r) access to the attribute holding the referral information (generally the ref attribute).

Some internal operations and some controls require specific access privileges.

The SASL authzID mapping and the LDAP proxyAuthz control require auth (=x) privileges on all the attributes that are present in the search filter of the URI regexp maps (the right-hand side of the authz-regexp directives). Auth (=x) privileges are also required on the authzTo attribute of the authorizing identity and/or on the authzFrom attribute of the authorized identity. In both cases, it is the authorizing identity that requires the privileges (i.e. the identity that has authenticated and is now trying to do some operation using another entity's permissions).

In general, when an internal lookup is performed for authentication or authorization purposes, search-specific privileges (see the access requirements for the search operation illustrated above) are relaxed to auth.

Access control to search entries is checked by the frontend, so it is fully honored by all backends; for all other operations and for the discovery phase of the search operation, full ACL semantics is only supported by the primary backends, i.e. slapd-mdb(5).

Some other backend, like slapd-sql(5), may fully support them; others may only support a portion of the described semantics, or even differ in some aspects. The relevant details are described in the backend-specific man pages.

## CAVEATS
It is strongly recommended to explicitly use the most appropriate <dnstyle> in <what> and <who> clauses, to avoid possible incorrect specifications of the access rules as well as for performance (avoid unnecessary regex matching when an exact match suffices) reasons.

An administrator might create a rule of the form:

```
	access to dn.regex="dc=example,dc=com"
		by ...
```

expecting it to match all entries in the subtree "dc=example,dc=com". However, this rule actually matches any DN which contains anywhere the substring "dc=example,dc=com". That is, the rule matches both "uid=joe,dc=example,dc=com" and "dc=example,dc=com,uid=joe".

To match the desired subtree, the rule would be more precisely written:

```
	access to dn.regex="^(.+,)?dc=example,dc=com$"
		by ...
```

For performance reasons, it would be better to use the subtree style.

```
	access to dn.subtree="dc=example,dc=com"
		by ...
```

When writing submatch rules, it may be convenient to avoid unnecessary regex <dnstyle> use; for instance, to allow access to the subtree of the user that matches the <what> clause, one could use

```
	access to dn.regex="^(.+,)?uid=([^,]+),dc=example,dc=com$"
		by dn.regex="^uid=$2,dc=example,dc=com$$" write
		by ...
```

However, since all that is required in the <by> clause is substring expansion, a more efficient solution is

```
	access to dn.regex="^(.+,)?uid=([^,]+),dc=example,dc=com$"
		by dn.exact,expand="uid=$2,dc=example,dc=com" write
		by ...
```

In fact, while a <dnstyle> of regex implies substring expansion, exact, as well as all the other DN specific <dnstyle> values, does not, so it must be explicitly requested.

## FILES
/etc/openldap/slapd.conf

default slapd configuration file

## SEE ALSO
slapd(8), slapd-*(5), slapacl(8), regex(7), re_format(7)

"OpenLDAP Administrator's Guide" (http://www.OpenLDAP.org/doc/admin/)

## ACKNOWLEDGEMENTS
OpenLDAP Software is developed and maintained by The OpenLDAP Project <http://www.openldap.org/>. OpenLDAP Software is derived from the University of Michigan LDAP 3.3 Release.


slapd.backends

title: slapd.backends(5)

text:
# slapd.backends(5)

## NAME
slapd.backends - backends for slapd, the stand-alone LDAP daemon

## DESCRIPTION
The slapd(8) daemon can use a variety of different backends for serving LDAP requests. Backends may be compiled statically into slapd, or when module support is enabled, they may be dynamically loaded. Multiple instances of a backend can be configured, to serve separate databases from the same slapd server.

Configuration options for each backend are documented separately in the corresponding slapd-<backend>(5) manual pages.

asyncmeta

This backend performs basic LDAP proxying with respect to a set of remote LDAP servers. It is an enhancement of the ldap backend that operates asynchronously, to prevent tying up slapd threads while waiting for operations to complete.

config

This backend is used to manage the configuration of slapd at run-time. Unlike other backends, only a single instance of the config backend may be defined. It also instantiates itself automatically, so it is always present even if not explicitly defined in the slapd.conf(5) file.

dnssrv

This backend is experimental. It serves up referrals based upon SRV resource records held in the Domain Name System.

ldap

This backend acts as a proxy to forward incoming requests to another LDAP server.

ldif

This database uses the filesystem to build the tree structure of the database, using plain ascii files to store data. Its usage should be limited to very simple databases, where performance is not a requirement. This backend also supports subtree renames.

mdb

This is the recommended primary backend. This backend uses OpenLDAP's own MDB transactional database library. This backend also supports subtree renames.

meta

This backend performs basic LDAP proxying with respect to a set of remote LDAP servers. It is an enhancement of the ldap backend.

monitor

This backend provides information about the running status of the slapd daemon. Only a single instance of the monitor backend may be defined.

null

Operations in this backend succeed but do nothing.

passwd

This backend is provided for demonstration purposes only. It serves up user account information from the system passwd(5) file.

perl

This backend embeds a perl(1) interpreter into slapd. It runs Perl subroutines to implement LDAP operations. This backend is deprecated.

relay

This backend is experimental. It redirects LDAP operations to another database in the same server, based on the naming context of the request. Its use requires the rwm overlay (see slapo-rwm(5) for details) to rewrite the naming context of the request. It is primarily intended to implement virtual views on databases that actually store data.

sql

This backend is experimental and deprecated. It services LDAP requests from an SQL database.

wiredtiger

This backend is experimental. It services LDAP requests from a wiredtiger database.

## FILES
/etc/openldap/slapd.conf

default slapd configuration file

/etc/openldap/slapd.d

default slapd configuration directory

## SEE ALSO
ldap(3), slapd-asyncmeta(5), slapd-config(5), slapd-dnssrv(5), slapd-ldap(5), slapd-ldif(5), slapd-mdb(5), slapd-meta(5), slapd-monitor(5), slapd-null(5), slapd-passwd(5), slapd-perl(5), slapd-relay(5), slapd-sql(5), slapd-wt(5), slapd.conf(5), slapd.overlays(5), slapd(8). "OpenLDAP Administrator's Guide" (http://www.OpenLDAP.org/doc/admin/)

## ACKNOWLEDGEMENTS
OpenLDAP Software is developed and maintained by The OpenLDAP Project <http://www.openldap.org/>. OpenLDAP Software is derived from the University of Michigan LDAP 3.3 Release.