6. The slapd Configuration File

This chapter describes configuring slapd(8) via the slapd.conf(5) configuration file. slapd.conf(5) has been deprecated and should only be used if your site requires one of the backends that hasn't yet been updated to work with the newer slapd-config(5) system. Configuring slapd(8) via slapd-config(5) is described in the previous chapter.

The slapd.conf(5) file is normally installed in the /usr/local/etc/openldap directory. An alternate configuration file location can be specified via a command-line option to slapd(8).


6.1. Configuration File Format

The slapd.conf(5) file consists of three types of configuration information: global, backend specific, and database specific. Global information is specified first, followed by information associated with a particular backend type, which is then followed by information associated with a particular database instance. Global directives can be overridden in backend and/or database directives, and backend directives can be overridden by database directives.

Blank lines and comment lines beginning with a '#' character are ignored. If a line begins with whitespace, it is considered a continuation of the previous line (even if the previous line is a comment).

The general format of slapd.conf is as follows:

        # global configuration directives
        <global config directives>

        # backend definition
        backend <typeA>
        <backend-specific directives>

        # first database definition & config directives
        database <typeA>
        <database-specific directives>

        # second database definition & config directives
        database <typeB>
        <database-specific directives>

        # second database definition & config directives
        database <typeA>
        <database-specific directives>

        # subsequent backend & database definitions & config directives
        ...

A configuration directive may take arguments. If so, they are separated by whitespace. If an argument contains whitespace, the argument should be enclosed in double quotes "like this". If an argument contains a double quote or a backslash character `\', the character should be preceded by a backslash character `\'.

The distribution contains an example configuration file that will be installed in the /usr/local/etc/openldap directory. A number of files containing schema definitions (attribute types and object classes) are also provided in the /usr/local/etc/openldap/schema directory.


6.2. Configuration File Directives

This section details commonly used configuration directives. For a complete list, see the slapd.conf(5) manual page. This section separates the configuration file directives into global, backend-specific and data-specific categories, describing each directive and its default value (if any), and giving an example of its use.

6.2.1. Global Directives

Directives described in this section apply to all backends and databases unless specifically overridden in a backend or database definition. Arguments that should be replaced by actual text are shown in brackets <>.

6.2.1.1. access to <what> [ by <who> [<accesslevel>] [<control>] ]+

This directive grants access (specified by <accesslevel>) to a set of entries and/or attributes (specified by <what>) by one or more requestors (specified by <who>). See the Access Control section of this guide for basic usage.


Note: If no access directives are specified, the default access control policy, access to * by * read, allows all both authenticated and anonymous users read access.

6.2.1.2. attributetype <RFC4512 Attribute Type Description>

This directive defines an attribute type. Please see the Schema Specification chapter for information regarding how to use this directive.

6.2.1.3. idletimeout <integer>

Specify the number of seconds to wait before forcibly closing an idle client connection. An idletimeout of 0, the default, disables this feature.

6.2.1.4. include <filename>

This directive specifies that slapd should read additional configuration information from the given file before continuing with the next line of the current file. The included file should follow the normal slapd config file format. The file is commonly used to include files containing schema specifications.


Note: You should be careful when using this directive - there is no small limit on the number of nested include directives, and no loop detection is done.

6.2.1.5. loglevel <level>

This directive specifies the level at which debugging statements and operation statistics should be syslogged (currently logged to the syslogd(8) LOG_LOCAL4 facility). You must have configured OpenLDAP --enable-debug (the default) for this to work (except for the two statistics levels, which are always enabled). Log levels may be specified as integers or by keyword. Multiple log levels may be used and the levels are additive. To display what numbers correspond to what kind of debugging, invoke slapd with -d? or consult the table below. The possible values for <integer> are:

Table 6.1: Debugging Levels
Level Keyword Description
-1 any enable all debugging
0   no debugging
1 (0x1 trace) trace function calls
2 (0x2 packets) debug packet handling
4 (0x4 args) heavy trace debugging
8 (0x8 conns) connection management
16 (0x10 BER) print out packets sent and received
32 (0x20 filter) search filter processing
64 (0x40 config) configuration processing
128 (0x80 ACL) access control list processing
256 (0x100 stats) stats log connections/operations/results
512 (0x200 stats2) stats log entries sent
1024 (0x400 shell) print communication with shell backends
2048 (0x800 parse) print entry parsing debugging
16384 (0x4000 sync) syncrepl consumer processing
32768 (0x8000 none) only messages that get logged whatever log level is set

The desired log level can be input as a single integer that combines the (ORed) desired levels, both in decimal or in hexadecimal notation, as a list of integers (that are ORed internally), or as a list of the names that are shown between brackets, such that

                loglevel 129
                loglevel 0x81
                loglevel 128 1
                loglevel 0x80 0x1
                loglevel acl trace

are equivalent.

Examples:

 loglevel -1

This will cause lots and lots of debugging information to be logged.

 loglevel conns filter

Just log the connection and search filter processing.

 loglevel none

Log those messages that are logged regardless of the configured loglevel. This differs from setting the log level to 0, when no logging occurs. At least the None level is required to have high priority messages logged.

Default:

 loglevel stats

Basic stats logging is configured by default. However, if no loglevel is defined, no logging occurs (equivalent to a 0 level).

6.2.1.6. objectclass <RFC4512 Object Class Description>

This directive defines an object class. Please see the Schema Specification chapter for information regarding how to use this directive.

6.2.1.7. referral <URI>

This directive specifies the referral to pass back when slapd cannot find a local database to handle a request.

Example:

        referral ldap://root.openldap.org

This will refer non-local queries to the global root LDAP server at the OpenLDAP Project. Smart LDAP clients can re-ask their query at that server, but note that most of these clients are only going to know how to handle simple LDAP URLs that contain a host part and optionally a distinguished name part.

6.2.1.8. sizelimit <integer>

This directive specifies the maximum number of entries to return from a search operation.

Default:

        sizelimit 500

See the Limits section of this guide and slapd.conf(5) for more details.

6.2.1.9. timelimit <integer>

This directive specifies the maximum number of seconds (in real time) slapd will spend answering a search request. If a request is not finished in this time, a result indicating an exceeded timelimit will be returned.

Default:

        timelimit 3600

See the Limits section of this guide and slapd.conf(5) for more details.

6.2.2. General Backend Directives

Directives in this section apply only to the backend in which they are defined. They are supported by every type of backend. Backend directives apply to all databases instances of the same type and, depending on the directive, may be overridden by database directives.

6.2.2.1. backend <type>

This directive marks the beginning of a backend declaration. <type> should be one of the supported backend types listed in Table 6.2.

Table 6.2: Database Backends
Types Description
bdb Berkeley DB transactional backend
dnssrv DNS SRV backend
hdb Hierarchical variant of bdb backend
ldap Lightweight Directory Access Protocol (Proxy) backend
meta Meta Directory backend
monitor Monitor backend
passwd Provides read-only access to passwd(5)
perl Perl Programmable backend
shell Shell (extern program) backend
sql SQL Programmable backend

Example:

        backend bdb

This marks the beginning of a new BDB backend definition.

6.2.3. General Database Directives

Directives in this section apply only to the database in which they are defined. They are supported by every type of database.

6.2.3.1. database <type>

This directive marks the beginning of a database instance declaration. <type> should be one of the supported backend types listed in Table 6.2.

Example:

        database bdb

This marks the beginning of a new BDB database instance declaration.

6.2.3.2. limits <who> <limit> [<limit> [...]]

Specify time and size limits based on who initiated an operation.

See the Limits section of this guide and slapd.conf(5) for more details.

6.2.3.3. readonly { on | off }

This directive puts the database into "read-only" mode. Any attempts to modify the database will return an "unwilling to perform" error.

Default:

        readonly off

6.2.3.4. rootdn <DN>

This directive specifies the DN that is not subject to access control or administrative limit restrictions for operations on this database. The DN need not refer to an entry in this database or even in the directory. The DN may refer to a SASL identity.

Entry-based Example:

        rootdn "cn=Manager,dc=example,dc=com"

SASL-based Example:

        rootdn "uid=root,cn=example.com,cn=digest-md5,cn=auth"

See the SASL Authentication section for information on SASL authentication identities.

6.2.3.5. rootpw <password>

This directive can be used to specifies a password for the DN for the rootdn (when the rootdn is set to a DN within the database).

Example:

        rootpw secret

It is also permissible to provide hash of the password in RFC2307 form. slappasswd(8) may be used to generate the password hash.

Example:

        rootpw {SSHA}ZKKuqbEKJfKSXhUbHG3fG8MDn9j1v4QN

The hash was generated using the command slappasswd -s secret.

6.2.3.6. suffix <dn suffix>

This directive specifies the DN suffix of queries that will be passed to this backend database. Multiple suffix lines can be given, and at least one is required for each database definition.

Example:

        suffix "dc=example,dc=com"

Queries with a DN ending in "dc=example,dc=com" will be passed to this backend.


Note: When the backend to pass a query to is selected, slapd looks at the suffix line(s) in each database definition in the order they appear in the file. Thus, if one database suffix is a prefix of another, it must appear after it in the config file.

6.2.3.7. syncrepl

        syncrepl rid=<replica ID>
                provider=ldap[s]://<hostname>[:port]
                [type=refreshOnly|refreshAndPersist]
                [interval=dd:hh:mm:ss]
                [retry=[<retry interval> <# of retries>]+]
                searchbase=<base DN>
                [filter=<filter str>]
                [scope=sub|one|base]
                [attrs=<attr list>]
                [attrsonly]
                [sizelimit=<limit>]
                [timelimit=<limit>]
                [schemachecking=on|off]
                [bindmethod=simple|sasl]
                [binddn=<DN>]
                [saslmech=<mech>]
                [authcid=<identity>]
                [authzid=<identity>]
                [credentials=<passwd>]
                [realm=<realm>]
                [secprops=<properties>]
                [starttls=yes|critical]
                [tls_cert=<file>]
                [tls_key=<file>]
                [tls_cacert=<file>]
                [tls_cacertdir=<path>]
                [tls_reqcert=never|allow|try|demand]
                [tls_ciphersuite=<ciphers>]
                [tls_crlcheck=none|peer|all]
                [logbase=<base DN>]
                [logfilter=<filter str>]
                [syncdata=default|accesslog|changelog]

This directive specifies the current database as a replica of the master content by establishing the current slapd(8) as a replication consumer site running a syncrepl replication engine. The master database is located at the replication provider site specified by the provider parameter. The replica database is kept up-to-date with the master content using the LDAP Content Synchronization protocol. See RFC4533 for more information on the protocol.

The rid parameter is used for identification of the current syncrepl directive within the replication consumer server, where <replica ID> uniquely identifies the syncrepl specification described by the current syncrepl directive. <replica ID> is non-negative and is no more than three decimal digits in length.

The provider parameter specifies the replication provider site containing the master content as an LDAP URI. The provider parameter specifies a scheme, a host and optionally a port where the provider slapd instance can be found. Either a domain name or IP address may be used for <hostname>. Examples are ldap://provider.example.com:389 or ldaps://192.168.1.1:636. If <port> is not given, the standard LDAP port number (389 or 636) is used. Note that the syncrepl uses a consumer-initiated protocol, and hence its specification is located at the consumer site, whereas the replica specification is located at the provider site. syncrepl and replica directives define two independent replication mechanisms. They do not represent the replication peers of each other.

The content of the syncrepl replica is defined using a search specification as its result set. The consumer slapd will send search requests to the provider slapd according to the search specification. The search specification includes searchbase, scope, filter, attrs, attrsonly, sizelimit, and timelimit parameters as in the normal search specification. The searchbase parameter has no default value and must always be specified. The scope defaults to sub, the filter defaults to (objectclass=*), attrs defaults to "*,+" to replicate all user and operational attributes, and attrsonly is unset by default. Both sizelimit and timelimit default to "unlimited", and only positive integers or "unlimited" may be specified.

The LDAP Content Synchronization protocol has two operation types: refreshOnly and refreshAndPersist. The operation type is specified by the type parameter. In the refreshOnly operation, the next synchronization search operation is periodically rescheduled at an interval time after each synchronization operation finishes. The interval is specified by the interval parameter. It is set to one day by default. In the refreshAndPersist operation, a synchronization search remains persistent in the provider slapd instance. Further updates to the master replica will generate searchResultEntry to the consumer slapd as the search responses to the persistent synchronization search.

If an error occurs during replication, the consumer will attempt to reconnect according to the retry parameter which is a list of the <retry interval> and <# of retries> pairs. For example, retry="60 10 300 3" lets the consumer retry every 60 seconds for the first 10 times and then retry every 300 seconds for the next three times before stop retrying. + in <# of retries> means indefinite number of retries until success.

The schema checking can be enforced at the LDAP Sync consumer site by turning on the schemachecking parameter. If it is turned on, every replicated entry will be checked for its schema as the entry is stored into the replica content. Every entry in the replica should contain those attributes required by the schema definition. If it is turned off, entries will be stored without checking schema conformance. The default is off.

The binddn parameter gives the DN to bind as for the syncrepl searches to the provider slapd. It should be a DN which has read access to the replication content in the master database.

The bindmethod is simple or sasl, depending on whether simple password-based authentication or SASL authentication is to be used when connecting to the provider slapd instance.

Simple authentication should not be used unless adequate data integrity and confidentiality protections are in place (e.g. TLS or IPsec). Simple authentication requires specification of binddn and credentials parameters.

SASL authentication is generally recommended. SASL authentication requires specification of a mechanism using the saslmech parameter. Depending on the mechanism, an authentication identity and/or credentials can be specified using authcid and credentials, respectively. The authzid parameter may be used to specify an authorization identity.

The realm parameter specifies a realm which a certain mechanisms authenticate the identity within. The secprops parameter specifies Cyrus SASL security properties.

The starttls parameter specifies use of the StartTLS extended operation to establish a TLS session before authenticating to the provider. If the critical argument is supplied, the session will be aborted if the StartTLS request fails. Otherwise the syncrepl session continues without TLS. Note that the main slapd TLS settings are not used by the syncrepl engine; by default the TLS parameters from a ldap.conf(5) configuration file will be used. TLS settings may be specified here, in which case any ldap.conf(5) settings will be completely ignored.

Rather than replicating whole entries, the consumer can query logs of data modifications. This mode of operation is referred to as delta syncrepl. In addition to the above parameters, the logbase and logfilter parameters must be set appropriately for the log that will be used. The syncdata parameter must be set to either "accesslog" if the log conforms to the slapo-accesslog(5) log format, or "changelog" if the log conforms to the obsolete changelog format. If the syncdata parameter is omitted or set to "default" then the log parameters are ignored.

The syncrepl replication mechanism is supported by the bdb and hdb backends.

See the LDAP Sync Replication chapter of this guide for more information on how to use this directive.

6.2.3.8. updateref <URL>

This directive is only applicable in a slave (or shadow) slapd(8) instance. It specifies the URL to return to clients which submit update requests upon the replica. If specified multiple times, each URL is provided.

Example:

        updateref       ldap://master.example.net

6.2.4. BDB and HDB Database Directives

Directives in this category only apply to both the BDB and the HDB database. That is, they must follow a "database bdb" or "database hdb" line and come before any subsequent "backend" or "database" line. For a complete reference of BDB/HDB configuration directives, see slapd-bdb(5).

6.2.4.1. directory <directory>

This directive specifies the directory where the BDB files containing the database and associated indices live.

Default:

        directory /usr/local/var/openldap-data

6.3. Configuration File Example

The following is an example configuration file, interspersed with explanatory text. It defines two databases to handle different parts of the X.500 tree; both are BDB database instances. The line numbers shown are provided for reference only and are not included in the actual file. First, the global configuration section:

  1.    # example config file - global configuration section
  2.    include /usr/local/etc/schema/core.schema
  3.    referral ldap://root.openldap.org
  4.    access to * by * read

Line 1 is a comment. Line 2 includes another config file which contains core schema definitions. The referral directive on line 3 means that queries not local to one of the databases defined below will be referred to the LDAP server running on the standard port (389) at the host root.openldap.org.

Line 4 is a global access control. It applies to all entries (after any applicable database-specific access controls).

The next section of the configuration file defines a BDB backend that will handle queries for things in the "dc=example,dc=com" portion of the tree. The database is to be replicated to two slave slapds, one on truelies, the other on judgmentday. Indices are to be maintained for several attributes, and the userPassword attribute is to be protected from unauthorized access.

  5.    # BDB definition for the example.com
  6.    database bdb
  7.    suffix "dc=example,dc=com"
  8.    directory /usr/local/var/openldap-data
  9.    rootdn "cn=Manager,dc=example,dc=com"
 10.    rootpw secret
 11.    # indexed attribute definitions
 12.    index uid pres,eq
 13.    index cn,sn pres,eq,approx,sub
 14.    index objectClass eq
 15.    # database access control definitions
 16.    access to attrs=userPassword
 17.        by self write
 18.        by anonymous auth
 19.        by dn.base="cn=Admin,dc=example,dc=com" write
 20.        by * none
 21.    access to *
 22.        by self write
 23.        by dn.base="cn=Admin,dc=example,dc=com" write
 24.        by * read

Line 5 is a comment. The start of the database definition is marked by the database keyword on line 6. Line 7 specifies the DN suffix for queries to pass to this database. Line 8 specifies the directory in which the database files will live.

Lines 9 and 10 identify the database super-user entry and associated password. This entry is not subject to access control or size or time limit restrictions.

Lines 12 through 14 indicate the indices to maintain for various attributes.

Lines 16 through 24 specify access control for entries in this database. For all applicable entries, the userPassword attribute is writable by the entry itself and by the "admin" entry. It may be used for authentication/authorization purposes, but is otherwise not readable. All other attributes are writable by the entry and the "admin" entry, but may be read by all users (authenticated or not).

The next section of the example configuration file defines another BDB database. This one handles queries involving the dc=example,dc=net subtree but is managed by the same entity as the first database. Note that without line 39, the read access would be allowed due to the global access rule at line 4.

 33.    # BDB definition for example.net
 34.    database bdb
 35.    suffix "dc=example,dc=net"
 36.    directory /usr/local/var/openldap-data-net
 37.    rootdn "cn=Manager,dc=example,dc=com"
 38.    index objectClass eq
 39.    access to * by users read