openldap/doc/man/man5/slapd.conf.5

.TH SLAPD.CONF 5 "RELEASEDATE" "OpenLDAP LDVERSION"
.\" Copyright 1998-2002 The OpenLDAP Foundation All Rights Reserved.
.\" Copying restrictions apply.  See COPYRIGHT/LICENSE.
.\" $OpenLDAP$
.SH NAME
slapd.conf \- configuration file for slapd, the stand-alone LDAP daemon
.SH SYNOPSIS
ETCDIR/slapd.conf
.SH DESCRIPTION
The file
.B ETCDIR/slapd.conf
contains configuration information for the
.BR slapd (8)
daemon.  This configuration file is also used by the
.BR slurpd (8)
replication daemon and by the SLAPD tools
.BR slapadd (8),
.BR slapcat (8),
and
.BR slapindex (8).
.LP
The
.B slapd.conf
file consists of a series of global configuration options that apply to
.B slapd
as a whole (including all backends), followed by zero or more database
backend definitions that contain information specific to a backend
instance.
.LP
The general format of
.B slapd.conf
is as follows:
.LP
.nf
    # 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
    ...
.fi
.LP
As many backend-specific sections as desired may be included.  Global
options can be overridden in a backend (for options that appear more
than once, the last appearance in the
.B slapd.conf
file is used).  Blank lines and comment lines beginning with a `#'
character are ignored. If a line begins with white space, it is
considered a continuation of the previous line.
.LP
Arguments on configuration lines are separated by white space. If an
argument contains white space, the argument should be enclosed in
double quotes.  If an argument contains a double quote (`"') or a
backslash character (`\\'), the character should be preceded by a
backslash character.
.LP
The specific configuration options available are discussed below in the
Global Configuration Options, General Backend Options, and General Database
Options.  Backend-specific options are discussed in the
.B slapd-<backend>(5)
manual pages.  Refer to the "OpenLDAP Administrator's Guide" for more
details on the slapd configuration file.
.SH GLOBAL CONFIGURATION OPTIONS
Options described in this section apply to all backends, unless specifically 
overridden in a backend definition. Arguments that should be replaced by 
actual text are shown in brackets <>.
.TP
.B 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>).
See
.BR slapd.access (5)
and the "OpenLDAP's Administrator's Guide" for details.
.TP
.B allow <features>
Specify a set of features (separated by white space) to
allow (default none).
.B bind_v2
allows acceptance of LDAPv2 bind requests.
.B bind_anon_cred
allows anonymous bind when credentials are not empty (e.g.
when DN is empty).
.B bind_anon_dn
allows unauthenticated (anonymous) bind when DN is not empty.
.B update_anon
allow unauthenticated (anonymous) update operations to be processed
(subject to access controls and other administrative limits).
.TP
.B argsfile <filename>
The ( absolute ) name of a file that will hold the 
.B slapd
server's command line options
if started without the debugging command line option.
.TP
.B attributeoptions [option-name]...
Define tagging attribute options or option tag/range prefixes.
Options must not end with `-', prefixes must end with `-'.
The `lang-' prefix is predefined.
If you use the
.B attributeoptions
directive, `lang-' will no longer be defined and you must specify it
explicitly if you want it defined.

An attribute description with a tagging option is a subtype of that
attribute description without the option.
Except for that, options defined this way have no special semantics.
Prefixes defined this way work like the `lang-' options:
They define a prefix for tagging options starting with the prefix.
That is, if you define the prefix `x-foo-', you can use the option
`x-foo-bar'.
Furthermore, in a search or compare, a prefix or range name (with
a trailing `-') matches all options starting with that name, as well
as the option with the range name sans the trailing `-'.
That is, `x-foo-bar-' matches `x-foo-bar' and `x-foo-bar-baz'.

RFC2251 reserves options beginning with `x-' for private experiments.
Other options should be registered with IANA, see RFC3383 section 3.4.
OpenLDAP also has the `binary' option built in, but this is a transfer
option, not a tagging option.
.HP
.hy 0
.B attributetype "(\ <oid> [NAME\ <name>] [OBSOLETE]\
 [DESC\ <description>]\
 [SUP\ <oid>] [EQUALITY\ <oid>] [ORDERING\ <oid>]\
 [SUBSTR\ <oid>] [SYNTAX\ <oidlen>] [SINGLE\-VALUE] [COLLECTIVE]\
 [NO\-USER\-MODIFICATION] [USAGE\ <attributeUsage>]\ )"
.RS
Specify an attribute type using the LDAPv3 syntax defined in RFC 2252.
The slapd parser extends the RFC 2252 definition by allowing string
forms as well as numeric OIDs to be used for the attribute OID and
attribute syntax OID.
(See the
.B objectidentifier
description.) 
.RE
.TP
.B concurrency <integer>
Specify a desired level of concurrency.  Provided to the underlying
thread system as a hint.  The default is not to provide any hint.
.\".TP
.\".B debug <subsys> <level>
.\"Specify a logging level for a particular subsystem.  The subsystems include
.\".B global
.\"a global level for all subsystems,
.\".B acl
.\"the ACL engine,
.\".B backend
.\"the backend databases,
.\".B cache
.\"the entry cache manager,
.\".B config
.\"the config file reader,
.\".B connection
.\"the connection manager,
.\".B cyrus
.\"the Cyrus SASL library interface,
.\".B filter
.\"the search filter processor,
.\".B getdn
.\"the DN normalization library,
.\".B index
.\"the database indexer,
.\".B liblber
.\"the ASN.1 BER library,
.\".B module
.\"the dynamic module loader,
.\".B operation
.\"the LDAP operation processors,
.\".B sasl
.\"the SASL authentication subsystem,
.\".B schema
.\"the schema processor, and
.\".B tls
.\"the TLS library interface. This is not an exhaustive list; there are many
.\"other subsystems and more are added over time.
.\"
.\"The levels are, in order of decreasing priority:
.\".B emergency, alert, critical, error, warning, notice, information, entry,
.\".B args, results, detail1, detail2
.\"An integer may be used instead, with 0 corresponding to
.\".B emergency
.\"up to 11 for
.\".BR detail2 .
.\"The
.\".B entry
.\"level logs function entry points,
.\".B args
.\"adds function call parameters, and
.\".B results
.\"adds the function results to the logs.
.\"The
.\".B detail1
.\"and
.\".B detail2
.\"levels add even more low level detail from individual functions.
.TP
.B defaultsearchbase <dn>
Specify a default search base to use when client submits a
non-base search request with an empty base DN.
.TP
.B disallow <features>
Specify a set of features (separated by white space) to
disallow (default none).
.B bind_anon
disables acceptance of anonymous bind requests.
.B bind_simple
disables simple (bind) authentication.
.B bind_simple_unprotected
disables simple (bind) authentication when confidentiality
protection (e.g. TLS) is not in place.  The
.B security
directive's
.B simple_bind
option provides fine grain control over the confidentiality
protection required for simple bind.
.B bind_krbv4
disables Kerberos V4 (bind) authentication.
.B tls_2_anon
disables Start TLS from forcing session to anonymous status (see also
.BR tls_authc ).
.B tls_authc
disables StartTLS if authenticated (see also
.BR tls_2_anon ).
.TP
.B gentlehup { on | off }
A SIGHUP signal will only cause a 'gentle' shutdown-attempt:
.B Slapd
will stop listening for new connections, but will not close the
connections to the current clients.  Future write operations return
unwilling-to-perform, though.  Slapd terminates when all clients
have closed their connections (if they ever do), or \- as before \-
if it receives a SIGTERM signal.  This can be useful if you wish to
terminate the server and start a new
.B slapd
server
.B with another database,
without disrupting the currently active clients.
The default is off.  You may wish to use
.B idletimeout
along with this option.
.TP
.B idletimeout <integer>
Specify the number of seconds to wait before forcibly closing
an idle client connection.  A idletimeout of 0 disables this
feature.  The default is 0.
.TP
.B include <filename>
Read additional configuration information from the given file before
continuing with the next line of the current file.
.TP
.B limits <who> <limit> [<limit> [...]]
Specify time and size limits based on who initiated an operation.
The argument
.B who
can be any of
.RS
.RS
.TP
anonymous | users | [dn[.<style>]=]<pattern>

.RE
with
.RS
.TP
<style> ::= exact | base | one | subtree | children | regex | anonymous

.RE
.B Anonymous
is hit when a search is performed without prior binding;
.B users
is hit when a search is performed by a successfully bound user;
otherwise a
.B regex
dn pattern is assumed unless otherwise specified by qualifying 
the (optional) key string
.B dn
with 
.B exact
or
.B base
(which are synonims), to require an exact match; with
.BR one, 
to require exactly one level of depth match; with
.BR subtree,
to allow any level of depth match, including the exact match; with
.BR children,
to allow any level of depth match, not including the exact match;
.BR regex
explicitly requires the (default) match based on regular expression
pattern, as detailed in
.BR regex (7).
Finally,
.B anonymous
matches unbound operations; the 
.B pattern
field is ignored.
The same behavior is obtained by using the 
.B anonymous
form of the
.B who
clause.

The currently supported limits are 
.B size
and 
.BR time.

The syntax for time limits is 
.BR time[.{soft|hard}]=<integer> ,
where 
.BR integer
is the number of seconds slapd will spend answering a search request.
If no time limit is explicitly requested by the client, the 
.BR soft
limit is used; if the requested time limit exceedes the
.BR hard
limit, an "Administrative limit exceeded" is returned.
If the
.BR hard
limit is set to 0 or to the keyword "soft", the soft limit is used 
in either case; if it is set to -1 or to the keyword "none", 
no hard limit is enforced.
Explicit requests for time limits smaller or equal to the
.BR hard 
limit are honored.
If no flag is set, the value is assigned to the 
.BR soft 
limit, and the
.BR hard
limit is set to zero, to preserve the original behavior.

The syntax for size limits is
.BR size[.{soft|hard|unchecked}]=<integer> ,
where
.BR integer
is the maximum number of entries slapd will return answering a search 
request.
If no size limit is explicitly requested by the client, the
.BR soft
limit is used; if the requested size limit exceedes the
.BR hard
limit, an "Administrative limit exceeded" is returned.
If the 
.BR hard
limit is set to 0 or to the keyword "soft", the soft limit is used 
in either case; if it is set to -1 or to the keyword "none", 
no hard limit is enforced.
Explicit requests for size limits smaller or equal to the
.BR hard
limit are honored.
The
.BR unchecked
flag sets a limit on the number of candidates a search request is allowed
to examine.
If the selected candidates exceed the 
.BR unchecked
limit, the search will abort with "Unwilling to perform".
If it is set to -1 or to the keyword "none", no limit is applied (the default).
If no flag is set, the value is assigned to the
.BR soft 
limit, and the
.BR hard
limit is set to zero, to preserve the original behavior.

In case of no match, the global limits are used.
The default values are the same of
.BR sizelimit
and
.BR timelimit ;
no limit is set on 
.BR unchecked .

If 
.B pagedResults
control is defined, additional size limits may be enforced; the syntax is
.BR size.pr={<integer>|noEstimate} ,
where
.BR integer
is the max page size if no explicit limit is set; the keyword
.BR noEstimate
inhibits the server to return an estimate of the total number
of entries that will be returned.
.RE
.\".TP
.\".B logfile <filename>
.\"Specify a file for recording debug log messages. By default these messages
.\"only go to stderr and are not recorded anywhere else. Specifying a logfile
.\"copies messages to both stderr and the logfile.
.TP
.B loglevel <integer>
Specify the level at which debugging statements and operation 
statistics should be syslogged (currently logged to the
.BR syslogd (8) 
LOG_LOCAL4 facility).  Log levels are additive, and available levels
are:
.RS
.RS
.PD 0
.TP
.B 1
trace function calls
.TP
.B 2
debug packet handling
.TP
.B 4
heavy trace debugging
.TP
.B 8
connection management
.TP
.B 16
print out packets sent and received
.TP
.B 32
search filter processing
.TP
.B 64
configuration file processing
.TP
.B 128
access control list processing
.TP
.B 256
stats log connections/operations/results
.TP
.B 512
stats log entries sent
.TP
.B 1024
print communication with shell backends
.TP
.B 2048
entry parsing
.PD
.RE
.RE
.TP
.B moduleload <filename>
Specify the name of a dynamically loadable module to load. The filename
may be an absolute path name or a simple filename. Non-absolute names
are searched for in the directories specified by the
.B modulepath
option. This option and the
.B modulepath
option are only usable if slapd was compiled with --enable-modules.
.TP
.B modulepath <pathspec>
Specify a list of directories to search for loadable modules. Typically
the path is colon-separated but this depends on the operating system.
.HP
.B objectclass "( <oid> [NAME <name>] [DESC <description] [OBSOLETE]\
 [SUP <oids>] [{ ABSTRACT | STRUCTURAL | AUXILIARY }] [MUST <oids>]\
 [MAY <oids>] )"
.RS
Specify an objectclass using the LDAPv3 syntax defined in RFC 2252.
The slapd parser extends the RFC 2252 definition by allowing string
forms as well as numeric OIDs to be used for the object class OID.
(See the
.B
objectidentifier
description.)  Object classes are "STRUCTURAL" by default.
.RE
.TP
.B objectidentifier <name> "{ <oid> | <name>[:<suffix>] }"
Define a string name that equates to the given OID. The string can be used
in place of the numeric OID in objectclass and attribute definitions. The
name can also be used with a suffix of the form ":xx" in which case the
value "oid.xx" will be used.
.TP
.B password-hash <hash>
This option sets the hash to be used in generation of user
passwords, stored in userPassword, during processing of
LDAP Password Modify Extended Operations (RFC 3052).
The <hash> must be one of
.BR {SSHA} ,
.BR {SHA} ,
.BR {SMD5} ,
.BR {MD5} ,
.BR {CRYPT} ,
and
.BR {CLEARTEXT} .
The default is
.BR {SSHA} .

.B {SHA}
and
.B {SSHA}
use the SHA-1 algorithm (FIPS 160-1), the latter with a seed.

.B {MD5}
and
.B {SMD5}
use the MD5 algorithm (RFC 1321), the latter with a seed.

.B {CRYPT}
uses the
.BR crypt (3).

.B {CLEARTEXT}
indicates that the new password should be
added to userPassword as clear text.

Note that this option does not alter the normal user applications
handling of userPassword during LDAP Add, Modify, or other LDAP operations.
.TP
.B password\-crypt\-salt\-format <format>
Specify the format of the salt passed to
.BR crypt (3)
when generating {CRYPT} passwords (see
.BR password\-hash )
during processing of LDAP Password Modify Extended Operations (RFC 3062).

This string needs to be in
.BR sprintf (3)
format and may include one (and only one) %s conversion.
This conversion will be substituted with a string random
characters from [A\-Za\-z0\-9./].  For example, "%.2s"
provides a two character salt and "$1$%.8s" tells some
versions of crypt(3) to use an MD5 algorithm and provides
8 random characters of salt.  The default is "%s", which
provides 31 characters of salt.
.TP
.B pidfile <filename>
The ( absolute ) name of a file that will hold the 
.B slapd
server's process ID ( see
.BR getpid (2)
) if started without the debugging command line option.
.TP
.B referral <url>
Specify the referral to pass back when
.BR slapd (8)
cannot find a local database to handle a request.
If specified multiple times, each url is provided.
.TP
.B require <conditions>
Specify a set of conditions (separated by white space) to
require (default none).
The directive may be specified globally and/or per-database.
.B bind
requires bind operation prior to directory operations.
.B LDAPv3
requires session to be using LDAP version 3.
.B authc
requires authentication prior to directory operations.
.B SASL
requires SASL authentication prior to directory operations.
.B strong
requires strong authentication prior to directory operations.
The strong keyword allows protected "simple" authentication
as well as SASL authentication.
.B none
may be used to require no conditions (useful for clearly globally
set conditions within a particular database).
.TP
.B reverse-lookup on | off
Enable/disable client name reverse lookup (default is 
.BR on 
if compiled with --enable-rlookups).
.TP
.B rootDSE <file>
Specify the name of an LDIF(5) file containing user defined attributes
for the root DSE.  These attributes are returned in addition to the
attributes normally produced by slapd.
.TP
.B sasl-authz-policy <policy>
Used to specify which rules to use for SASL Proxy Authorization. Proxy
authorization allows a client to authenticate to the server using one
user's credentials, but specify a different identity to use for authorization
and access control purposes. It essentially allows user A to login as user
B, using user A's password.
The
.B none
flag disables proxy authorization. This is the default setting.
The
.B from
flag will use rules in the
.I saslAuthzFrom
attribute of the authorization DN.
The
.B to
flag will use rules in the
.I saslAuthzTo
attribute of the authentication DN.
The
.B both
flag will allow both of the above. The rules are simply regular expressions
specifying which DNs are allowed to perform proxy authorization. The
.I saslAuthzFrom
attribute in an entry specifies which other users
are allowed to proxy login to this entry. The
.I saslAuthzTo
attribute in
an entry specifies which other users this user can authorize as.  Use of
.I saslAuthzTo
rules can be easily
abused if users are allowed to write arbitrary values to this attribute.
In general the
.I saslAuthzTo
attribute must be protected with ACLs such that
only privileged users can modify it.
.TP
.B sasl-host <fqdn>
Used to specify the fully qualified domain name used for SASL processing.
.TP
.B sasl-realm <realm>
Specify SASL realm.  Default is empty.
.TP
.B sasl-regexp <match> <replace>
Used by the SASL authorization mechanism to convert a SASL authenticated 
username to an LDAP DN. When an authorization request is received, the SASL 
.B USERNAME, REALM, 
and
.B MECHANISM
are taken, when available, and combined into a SASL name of the 
form
.RS
.RS
.TP
.B uid=<username>[,cn=<realm>],cn=<mechanism>,cn=auth

.RE
This SASL name is then compared against the
.B match
regular expression, and if the match is successful, the SASL name is
replaced with the
.B replace
string. If there are wildcard strings in the 
.B match
regular expression that are enclosed in parenthesis, e.g. 
.RS
.RS
.TP
.B uid=(.*),cn=.*

.RE
.RE
then the portion of the SASL name that matched the wildcard will be stored
in the numbered placeholder variable $1. If there are other wildcard strings
in parenthesis, the matching strings will be in $2, $3, etc. up to $9. The 
placeholders can then be used in the 
.B replace
string, e.g. 
.RS
.RS
.TP
.B cn=$1,ou=Accounts,dc=$2,dc=$4. 

.RE
.RE
The replaced SASL name can be either a DN or an LDAP URI. If the latter, the slapd
server will use the URI to search its own database, and if the search returns 
exactly one entry, the SASL name is replaced by the DN of that entry.
Multiple 
.B sasl-regexp 
options can be given in the configuration file to allow for multiple matching 
and replacement patterns. The matching patterns are checked in the order they 
appear in the file, stopping at the first successful match.

.\".B Caution:
.\"Because the plus sign + is a character recognized by the regular expression engine,
.\"and it will appear in SASL names that include a REALM, be careful to escape the
.\"plus sign with a backslash \\+ to remove the character's special meaning.
.RE
.TP
.B sasl-secprops <properties>
Used to specify Cyrus SASL security properties.
The
.B none
flag (without any other properities) causes the flag properites
default, "noanonymous,noplain", to be cleared.
The
.B noplain
flag disables mechanisms susceptible to simple passive attacks.
The
.B noactive
flag disables mechanisms susceptible to active attacks.
The
.B nodict
flag disables mechanisms susceptible to passive dictionary attacks.
The
.B noanonyous
flag disables mechanisms which support anonymous login.
The
.B forwardsec
flag require forward secrecy between sessions.
The
.B passcred
require mechanisms which pass client credentials (and allow
mechanisms which can pass credentials to do so).
The
.B minssf=<factor> 
property specifies the minimum acceptable
.I security strength factor
as an integer approximate to effective key length used for
encryption.  0 (zero) implies no protection, 1 implies integrity
protection only, 56 allows DES or other weak ciphers, 112
allows triple DES and other strong ciphers, 128 allows RC4,
Blowfish and other modern strong ciphers.  The default is 0.
The
.B maxssf=<factor> 
property specifies the maximum acceptable
.I security strength factor
as an integer (see minssf description).  The default is INT_MAX.
The
.B maxbufsize=<size> 
property specifies the maximum security layer receive buffer
size allowed.  0 disables security layers.  The default is 65536.
.TP
.B schemadn <dn>
Specify the distinguished name for the subschema subentry that
controls the entries on this server.  The default is "cn=Subschema".
.TP
.B security <factors>
Specify a set of factors (separated by white space) to require.
An integer value is associated with each factor and is roughly
equivalent of the encryption key length to require.  A value
of 112 is equivalent to 3DES, 128 to Blowfish, etc..
The directive may be specified globally and/or per-database.
.B ssf=<n>
specifies the overall security strength factor.
.B transport=<n>
specifies the transport security strength factor.
.B tls=<n>
specifies the TLS security strength factor.
.B sasl=<n>
specifies the SASL security strength factor.
.B update_ssf=<n>
specifies the overall security strength factor to require for
directory updates.
.B update_transport=<n>
specifies the transport security strength factor to require for
directory updates.
.B update_tls=<n>
specifies the TLS security strength factor to require for
directory updates.
.B update_sasl=<n>
specifies the SASL security strength factor to require for
directory updates.
.B simple_bind=<n>
specifies the security strength factor required for
.I simple
username/password authentication.
Note that the
.B transport
factor is measure of security provided by the underlying transport,
e.g. ldapi:// (and eventually IPSEC).  It is not normally used.
.TP
.B sizelimit {<integer>|unlimited}
.TP
.B sizelimit size[.{soft|hard|unchecked}]=<integer> [...]
Specify the maximum number of entries to return from a search operation.
The default size limit is 500.
Use
.B -1
or 
.B unlimited
to specify no limits.
The second format allows a fine grain setting of the size limits.
Extra args can be added on the same line.
See
.BR limits
for an explanation of the different flags.
.TP
.B sockbuf_max_incoming <integer>
Specify the maximum incoming LDAP PDU size for anonymous sessions.
The default is 262143.
.TP
.B sockbuf_max_incoming_auth <integer>
Specify the maximum incoming LDAP PDU size for authenticated sessions.
The default is 4194303.
.TP
.B srvtab <filename>
Specify the srvtab file in which the kerberos keys necessary for
authenticating clients using kerberos can be found. This option is only
meaningful if you are using Kerberos authentication.
.TP
.B threads <integer>
Specify the maximum size of the primary thread pool.
The default is 32.
.TP
.B timelimit {<integer>|unlimited}
.TP
.B timelimit time[.{soft|hard}]=<integer> [...]
Specify the maximum number of seconds (in real time)
.B slapd
will spend answering a search request.  The default time limit is 3600.
Use
.B -1
or 
.B unlimited
to specify no limits.
The second format allows a fine grain setting of the time limits.
Extra args can be added on the same line.
See
.BR limits
for an explanation of the different flags.
.TP
.B ucdata-path <path>
Specify the path to the directory containing the Unicode character
tables. The default path is LOCALSTATEDIR/ucdata.
.SH TLS OPTIONS
If
.B slapd
is built with support for Transport Layer Security, there are more options
you can specify.
.TP
.B TLSCipherSuite <cipher-suite-spec>
Permits configuring what ciphers will be accepted and the preference order.
<cipher-suite-spec> should be a cipher specification for OpenSSL.  Example:

TLSCipherSuite HIGH:MEDIUM:+SSLv2

To check what ciphers a given spec selects, use:

openssl ciphers -v <cipher-suite-spec>
.TP
.B TLSCACertificateFile <filename>
Specifies the file that contains certificates for all of the Certificate
Authorities that
.B slapd
will recognize.
.TP
.B TLSCACertificatePath <path>
Specifies the path of a directory that contains Certificate Authority
certificates in separate individual files. Usually only one of this
or the TLSCACertificateFile is used.
.TP
.B TLSCertificateFile <filename>
Specifies the file that contains the
.B slapd
server certificate.
.TP
.B TLSCertificateKeyFile <filename>
Specifies the file that contains the
.B slapd
server private key that matches the certificate stored in the
.B TLSCertificateFile
file.  Currently, the private key must not be protected with a password, so
it is of critical importance that it is protected carefully. 
.TP
.B TLSRandFile <filename>
Specifies the file to obtain random bits from when /dev/[u]random
is not available.  Generally set to the name of the EGD/PRNGD socket.
The environment variable RANDFILE can also be used to specify the filename.
.TP
.B TLSVerifyClient <level>
Specifies what checks to perform on client certificates in an
incoming TLS session, if any.
The
.B <level>
can be specified as one of the following keywords:
.RS
.TP
.B never
This is the default.
.B slapd
will not ask the client for a certificate.
.TP
.B allow
The client certificate is requested.  If no certificate is provided,
the session proceeds normally.  If a bad certificate is provided,
it will be ignored and the session proceeds normally.
.TP
.B try
The client certificate is requested.  If no certificate is provided,
the session proceeds normally.  If a bad certificate is provided,
the session is immediately terminated.
.TP
.B demand | hard | true
These keywords are all equivalent, for compatibility reasons.
The client certificate is requested.  If no certificate is provided,
or a bad certificate is provided, the session is immediately terminated.

Note that a valid client certificate is required in order to use the
SASL EXTERNAL authentication mechanism with a TLS session.  As such,
a non-default
.B TLSVerifyClient
setting must be chosen to enable SASL EXTERNAL authentication.
.RE
.SH GENERAL BACKEND OPTIONS
Options in this section only apply to the configuration file section
for the specified backend.  They are supported by every
type of backend.
.TP
.B backend <databasetype>
Mark the beginning of a backend definition. <databasetype>
should be one of
.B bdb,
.B dnssrv,
.B ldap,
.B ldbm,
.B meta,
.B monitor,
.B null,
.B passwd,
.B perl,
.B shell,
.B sql,
or
.B tcl,
depending on which backend will serve the database.

.SH GENERAL DATABASE OPTIONS
Options in this section only apply to the configuration file section
for the database in which they are defined.  They are supported by every
type of backend.  Note that the
.B database
and at least one
.B suffix
option are mandatory for each database.
.TP
.B database <databasetype>
Mark the beginning of a new database instance definition. <databasetype>
should be one of
.B bdb,
.B dnssrv,
.B ldap,
.B ldbm,
.B meta,
.B monitor,
.B null,
.B passwd,
.B perl,
.B shell,
.B sql,
or
.B tcl,
depending on which backend will serve the database.
.TP
.B lastmod on | off
Controls whether
.B slapd
will automatically maintain the 
modifiersName, modifyTimestamp, creatorsName, and 
createTimestamp attributes for entries.  By default, lastmod is on.
.TP
.B maxderefdepth <depth>
Specifies the maximum number of aliases to dereference when trying to
resolve an entry, used to avoid inifinite alias loops. The default is 1.
.TP
.B readonly on | off
This option puts the database into "read-only" mode.  Any attempts to 
modify the database will return an "unwilling to perform" error.  By
default, readonly is off.
.HP
.B replica host=<hostname>[:port] [tls=yes|critical]
.B [suffix=<suffix> [...]]
.B bindmethod=simple|sasl [binddn=<simple DN>] [credentials=<simple password>]
.B [saslmech=<SASL mech>] [secprops=<properties>] [realm=<realm>]
.B [authcId=<authentication ID>] [authzId=<authorization ID>]
.B [attr[!]=<attr list>]
.RS
Specify a replication site for this database.  Refer to the "OpenLDAP 
Administrator's Guide" for detailed information on setting up a replicated
.B slapd
directory service. Zero or more
.B suffix
instances can be used to select the subtrees that will be replicated
(defaults to all the database). A
.B bindmethod
of
.B simple
requires the options
.B binddn 
and
.B credentials  
and should only be used when adequate security services 
(e.g TLS or IPSEC) are in place. A
.B bindmethod 
of
.B sasl 
requires the option
.B saslmech. 
Specific security properties (as with the
.B sasl-secprops
keyword above) for a SASL bind can be set with the
.B secprops
option. A non-default SASL realm can be set with the
.B realm
option.
If the 
.B mechanism
will use Kerberos, a kerberos instance should be given in 
.B authcId.
An
.B attr list
can be given after the 
.B attr
keyword to allow the selective replication of the listed attributes only;
if the optional 
.B !
mark is used, the list is considered exclusive, i.e. the listed attributes
are not replicated.
If an objectClass is listed, all the related attributes
are (are not) replicated.
.RE
.TP
.B replogfile <filename>
Specify the name of the replication log file to log changes to.  
The replication log is typically written by
.BR slapd (8)
and read by
.BR slurpd (8).
See
.BR slapd.replog (5)
for more information.  The specified file should be located
in a directory with limited read/write/execute access as the replication
logs may contain sensitive information.
.TP
.B rootdn <dn>
Specify the distinguished name that is not subject to access control 
or administrative limit restrictions for operations on this database.
This DN may or may not be associated with an entry.  An empty root
DN (the default) specifies no root access is to be granted.  It is
recommended that the rootdn only be specified when needed (such as
when initially populating a database).  If the rootdn is within
a namingContext (suffix) of the database, a simple bind password
may also be provided using the
.B rootpw
directive.
.TP
.B rootpw <password>
Specify a password (or hash of the password) for the rootdn.  The
password can only be set if the rootdn is within the namingContext
(suffix) of the database.
This option accepts all RFC 2307 userPassword formats known to
the server (see 
.B password-hash
desription) as well as cleartext.
.BR slappasswd (8) 
may be used to generate a hash of a password.  Cleartext
and \fB{CRYPT}\fP passwords are not recommended.  If empty
(the default), authentication of the root DN is by other means
(e.g. SASL).  Use of SASL is encouraged.
.TP
.B suffix <dn suffix>
Specify 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.
If the suffix of one database is "inside" that of another, the database
with the inner suffix must come first in the configuration file.
.TP
.B suffixalias <alias> <aliased suffix>
Specify an alternate suffix that may be used to reference an already defined
database suffix. Operations specifying DNs residing under the alias 
will execute as if they had specified the aliased suffix.
.TP
.B subordinate
Specify that the current backend database is a subordinate of another
backend database. A subordinate database may have only one suffix. This
option may be used to glue multiple databases into a single namingContext.
If the suffix of the current database is within the namingContext of a
superior database, searches against the superior database will be
propagated to the subordinate as well. All of the databases
associated with a single namingContext should have identical rootdns.
Behavior of other LDAP operations is unaffected by this setting. In
particular, it is not possible to use moddn to move an entry from
one subordinate to another subordinate within the namingContext.
.TP
.B updatedn <dn>
This option is only applicable in a slave
.B slapd.
It specifies the DN allowed to make changes to the replica (typically,
this is the DN
.BR slurpd (8)
binds as when making changes to the replica).
.TP
.B updateref <url>
Specify the referral to pass back when
.BR slapd (8)
is asked to modify a replicated local database.
If specified multiple times, each url is provided.
.SH DATABASE-SPECIFIC OPTIONS
Each database may allow specific configuration options; they are
documented separately in the
.BR slapd-<backend> (5)
manual pages.
.SH EXAMPLES
.LP
Here is a short example of a configuration file:
.LP
.RS
.nf
include   SYSCONFDIR/schema/core.schema
pidfile   LOCALSTATEDIR/slapd.pid

# Subtypes of "name" (e.g. "cn" and "ou") with the
# option ";x-hidden" can be searched for/compared,
# but are not shown.  See \fBslapd.access\fP(5).
attributeoptions x-hidden lang-
access to attr=name;x-hidden by * =cs

database  bdb
suffix    "dc=our-domain,dc=com"
# The database directory MUST exist prior to
# running slapd AND should only be accessible
# by the slapd/tools. Mode 700 recommended.
directory LOCALSTATEDIR/openldap-data
# Indices to maintain
index     objectClass  eq
index     cn,sn,mail   pres,eq,approx,sub

# We serve small clients that do not handle referrals,
# so handle remote lookups on their behalf.
database  ldap
suffix    ""
uri       ldap://ldap.some-server.com/
lastmod   off
.fi
.RE
.LP
"OpenLDAP Administrator's Guide" contains a longer annotated
example of a configuration file.
The original ETCDIR/slapd.conf is another example.
.SH FILES
.TP
ETCDIR/slapd.conf
default slapd configuration file
.SH SEE ALSO
.BR ldap (3),
.BR slapd-bdb (5),
.BR slapd-dnssrv (5),
.BR slapd-ldap (5),
.BR slapd-ldbm (5),
.BR slapd-meta (5),
.BR slapd-null (5),
.BR slapd-passwd (5),
.BR slapd-perl (5),
.BR slapd-shell (5),
.BR slapd-sql (5),
.BR slapd-tcl (5),
.BR slapd.replog (5),
.BR slapd.access (5),
.BR locale (5),
.BR slapd (8),
.BR slapadd (8),
.BR slapcat (8),
.BR slapindex (8),
.BR slappassword (8),
.BR slurpd (8),
.LP
"OpenLDAP Administrator's Guide" (http://www.OpenLDAP.org/doc/admin/)
.SH ACKNOWLEDGEMENTS
.B	OpenLDAP
is developed and maintained by The OpenLDAP Project (http://www.openldap.org/).
.B	OpenLDAP
is derived from University of Michigan LDAP 3.3 Release.