ldap.conf(5) File Formats Manual ldap.conf(5)
NAME
ldap.conf, .ldaprc - LDAP configuration file/environment variables
SYNOPSIS
/opt/local/etc/openldap/ldap.conf, ldaprc, .ldaprc, $LDAP<option-name>
DESCRIPTION
If the environment variable LDAPNOINIT is defined, all defaulting is
disabled.
The ldap.conf configuration file is used to set system-wide defaults to
be applied when running ldap clients.
Users may create an optional configuration file, ldaprc or .ldaprc, in
their home directory which will be used to override the system-wide
defaults file. The file ldaprc in the current working directory is
also used.
Additional configuration files can be specified using the LDAPCONF and
LDAPRC environment variables. LDAPCONF may be set to the path of a
configuration file. This path can be absolute or relative to the
current working directory. The LDAPRC, if defined, should be the
basename of a file in the current working directory or in the user's
home directory.
Environmental variables may also be used to augment the file based
defaults. The name of the variable is the option name with an added
prefix of LDAP. For example, to define BASE via the environment, set
the variable LDAPBASE to the desired value.
Some options are user-only. Such options are ignored if present in the
ldap.conf (or file specified by LDAPCONF).
Thus the following files and variables are read, in order:
variable $LDAPNOINIT, and if that is not set:
system file /opt/local/etc/openldap/ldap.conf,
user files $HOME/ldaprc, $HOME/.ldaprc, ./ldaprc,
system file $LDAPCONF,
user files $HOME/$LDAPRC, $HOME/.$LDAPRC, ./$LDAPRC,
variables $LDAP<uppercase option name>.
Settings late in the list override earlier ones.
SYNTAX
The configuration options are case-insensitive; their value, on a case
by case basis, may be case-sensitive.
Blank lines are ignored.
Lines beginning with a hash mark (`#') are comments, and ignored.
Valid lines are made of an option's name (a sequence of non-blanks,
conventionally written in uppercase, although not required), followed
by a value. The value starts with the first non-blank character after
the option's name, and terminates at the end of the line, or at the
last sequence of blanks before the end of the line. The tokenization
of the value, if any, is delegated to the handler(s) for that option,
if any. Quoting values that contain blanks may be incorrect, as the
quotes would become part of the value. For example,
# Wrong - erroneous quotes:
URI "ldap:// ldaps://"
# Right - space-separated list of URIs, without quotes:
URI ldap:// ldaps://
# Right - DN syntax needs quoting for Example, Inc:
BASE ou=IT staff,o="Example, Inc",c=US
# or:
BASE ou=IT staff,o=Example\2C Inc,c=US
# Wrong - comment on same line as option:
DEREF never # Never follow aliases
A line cannot be longer than LINE_MAX, which should be more than 2000
bytes on all platforms. There is no mechanism to split a long line on
multiple lines, either for beautification or to overcome the above
limit.
OPTIONS
The different configuration options are:
URI <ldap[si]://[name[:port]] ...>
Specifies the URI(s) of an LDAP server(s) to which the LDAP
library should connect. The URI scheme may be any of ldap,
ldaps or ldapi, which refer to LDAP over TCP, LDAP over SSL
(TLS) and LDAP over IPC (UNIX domain sockets), respectively.
Each server's name can be specified as a domain-style name or an
IP address literal. Optionally, the server's name can followed
by a ':' and the port number the LDAP server is listening on.
If no port number is provided, the default port for the scheme
is used (389 for ldap://, 636 for ldaps://). For LDAP over IPC,
name is the name of the socket, and no port is required, nor
allowed; note that directory separators must be URL-encoded,
like any other characters that are special to URLs; so the
socket
/usr/local/var/ldapi
must be specified as
ldapi://%2Fusr%2Flocal%2Fvar%2Fldapi
A space separated list of URIs may be provided.
BASE <base>
Specifies the default base DN to use when performing ldap
operations. The base must be specified as a Distinguished Name
in LDAP format.
BINDDN <dn>
Specifies the default bind DN to use when performing ldap
operations. The bind DN must be specified as a Distinguished
Name in LDAP format. This is a user-only option.
DEREF <when>
Specifies how alias dereferencing is done when performing a
search. The <when> can be specified as one of the following
keywords:
never Aliases are never dereferenced. This is the default.
searching
Aliases are dereferenced in subordinates of the base
object, but not in locating the base object of the
search.
finding
Aliases are only dereferenced when locating the base
object of the search.
always Aliases are dereferenced both in searching and in
locating the base object of the search.
HOST <name[:port] ...>
Specifies the name(s) of an LDAP server(s) to which the LDAP
library should connect. Each server's name can be specified as
a domain-style name or an IP address and optionally followed by
a ':' and the port number the ldap server is listening on. A
space separated list of hosts may be provided. HOST is
deprecated in favor of URI.
KEEPALIVE_IDLE
Sets/gets the number of seconds a connection needs to remain
idle before TCP starts sending keepalive probes. Linux only.
KEEPALIVE_PROBES
Sets/gets the maximum number of keepalive probes TCP should send
before dropping the connection. Linux only.
KEEPALIVE_INTERVAL
Sets/gets the interval in seconds between individual keepalive
probes. Linux only.
NETWORK_TIMEOUT <integer>
Specifies the timeout (in seconds) after which the
poll(2)/select(2) following a connect(2) returns in case of no
activity.
PORT <port>
Specifies the default port used when connecting to LDAP
servers(s). The port may be specified as a number. PORT is
deprecated in favor of URI.
REFERRALS <on/true/yes/off/false/no>
Specifies if the client should automatically follow referrals
returned by LDAP servers. The default is on. Note that the
command line tools ldapsearch(1) &co always override this
option.
SIZELIMIT <integer>
Specifies a size limit (number of entries) to use when
performing searches. The number should be a non-negative
integer. SIZELIMIT of zero (0) specifies a request for
unlimited search size. Please note that the server may still
apply any server-side limit on the amount of entries that can be
returned by a search operation.
SOCKET_BIND_ADDRESSES <IP>
Specifies the source bind IP to be used for connecting to target
LDAP server. Multiple IP addresses must be space separated.
Only one valid IPv4 address and/or one valid IPv6 address are
allowed in the list.
TIMELIMIT <integer>
Specifies a time limit (in seconds) to use when performing
searches. The number should be a non-negative integer.
TIMELIMIT of zero (0) specifies unlimited search time to be
used. Please note that the server may still apply any server-
side limit on the duration of a search operation.
VERSION {2|3}
Specifies what version of the LDAP protocol should be used.
TIMEOUT <integer>
Specifies a timeout (in seconds) after which calls to
synchronous LDAP APIs will abort if no response is received.
Also used for any ldap_result(3) calls where a NULL timeout
parameter is supplied.
SASL OPTIONS
If OpenLDAP is built with Simple Authentication and Security Layer
support, there are more options you can specify.
SASL_MECH <mechanism>
Specifies the SASL mechanism to use.
SASL_REALM <realm>
Specifies the SASL realm.
SASL_AUTHCID <authcid>
Specifies the authentication identity. This is a user-only
option.
SASL_AUTHZID <authcid>
Specifies the proxy authorization identity. This is a user-only
option.
SASL_SECPROPS <properties>
Specifies Cyrus SASL security properties. The <properties> can
be specified as a comma-separated list of the following:
none (without any other properties) causes the properties
defaults ("noanonymous,noplain") to be cleared.
noplain
disables mechanisms susceptible to simple passive
attacks.
noactive
disables mechanisms susceptible to active attacks.
nodict disables mechanisms susceptible to passive dictionary
attacks.
noanonymous
disables mechanisms which support anonymous login.
forwardsec
requires forward secrecy between sessions.
passcred
requires mechanisms which pass client credentials (and
allows mechanisms which can pass credentials to do so).
minssf=<factor>
specifies the minimum acceptable security strength factor
as an integer approximate to effective key length used
for encryption. 0 (zero) implies no protection, 1
implies integrity protection only, 128 allows RC4,
Blowfish and other similar ciphers, 256 will require
modern ciphers. The default is 0.
maxssf=<factor>
specifies the maximum acceptable security strength factor
as an integer (see minssf description). The default is
INT_MAX.
maxbufsize=<factor>
specifies the maximum security layer receive buffer size
allowed. 0 disables security layers. The default is
65536.
SASL_NOCANON <on/true/yes/off/false/no>
Do not perform reverse DNS lookups to canonicalize SASL host
names. The default is off.
SASL_CBINDING <none/tls-unique/tls-endpoint>
The channel-binding type to use, see also
LDAP_OPT_X_SASL_CBINDING. The default is none.
GSSAPI OPTIONS
If OpenLDAP is built with Generic Security Services Application
Programming Interface support, there are more options you can specify.
GSSAPI_SIGN <on/true/yes/off/false/no>
Specifies if GSSAPI signing (GSS_C_INTEG_FLAG) should be used.
The default is off.
GSSAPI_ENCRYPT <on/true/yes/off/false/no>
Specifies if GSSAPI encryption (GSS_C_INTEG_FLAG and
GSS_C_CONF_FLAG) should be used. The default is off.
GSSAPI_ALLOW_REMOTE_PRINCIPAL <on/true/yes/off/false/no>
Specifies if GSSAPI based authentication should try to form the
target principal name out of the ldapServiceName or dnsHostName
attribute of the targets RootDSE entry. The default is off.
TLS OPTIONS
If OpenLDAP is built with Transport Layer Security support, there are
more options you can specify. These options are used when an ldaps://
URI is selected (by default or otherwise) or when the application
negotiates TLS by issuing the LDAP StartTLS operation.
TLS_CACERT <filename>
Specifies the file that contains certificates for all of the
Certificate Authorities the client will recognize.
TLS_CACERTDIR <path>
Specifies the path of directories that contain Certificate
Authority certificates in separate individual files. Multiple
directories may be specified, separated by a semi-colon. The
TLS_CACERT is always used before TLS_CACERTDIR.
TLS_CERT <filename>
Specifies the file that contains the client certificate. This
is a user-only option.
TLS_ECNAME <name>
Specify the name of the curve(s) to use for Elliptic curve
Diffie-Hellman ephemeral key exchange. This option is only used
for OpenSSL. This option is not used with GnuTLS; the curves
may be chosen in the GnuTLS ciphersuite specification.
TLS_KEY <filename>
Specifies the file that contains the private key that matches
the certificate stored in the TLS_CERT file. Currently, the
private key must not be protected with a password, so it is of
critical importance that the key file is protected carefully.
This is a user-only option.
TLS_CIPHER_SUITE <cipher-suite-spec>
Specifies acceptable cipher suite and preference order.
<cipher-suite-spec> should be a cipher specification for the TLS
library in use (OpenSSL or GnuTLS). Example:
OpenSSL:
TLS_CIPHER_SUITE HIGH:MEDIUM:+SSLv2
GnuTLS:
TLS_CIPHER_SUITE SECURE256:!AES-128-CBC
To check what ciphers a given spec selects in OpenSSL, use:
openssl ciphers -v <cipher-suite-spec>
With GnuTLS the available specs can be found in the manual page
of gnutls-cli(1) (see the description of the option --priority).
In older versions of GnuTLS, where gnutls-cli does not support
the option --priority, you can obtain the -- more limited --
list of ciphers by calling:
gnutls-cli -l
TLS_PROTOCOL_MIN <major>[.<minor>]
Specifies minimum SSL/TLS protocol version that will be
negotiated. If the server doesn't support at least that
version, the SSL handshake will fail. To require TLS 1.x or
higher, set this option to 3.(x+1), e.g.,
TLS_PROTOCOL_MIN 3.2
would require TLS 1.1. Specifying a minimum that is higher than
that supported by the OpenLDAP implementation will result in it
requiring the highest level that it does support. This
parameter is ignored with GnuTLS.
TLS_RANDFILE <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. This parameter is ignored
with GnuTLS.
TLS_REQCERT <level>
Specifies what checks to perform on server certificates in a TLS
session. The <level> can be specified as one of the following
keywords:
never The client will not request or check any server
certificate.
allow The server certificate is requested. If a bad certificate
is provided, it will be ignored and the session proceeds
normally.
try The server certificate is requested. If a bad certificate
is provided, the session is immediately terminated.
demand | hard
These keywords are equivalent and the same as try. This
is the default setting.
TLS_REQSAN <level>
Specifies what checks to perform on the subjectAlternativeName
(SAN) extensions in a server certificate when validating the
certificate name against the specified hostname of the server.
The <level> can be specified as one of the following keywords:
never The client will not check any SAN in the certificate.
allow The SAN is checked against the specified hostname. If a
SAN is present but none match the specified hostname, the
SANs are ignored and the usual check against the
certificate DN is used. This is the default setting.
try The SAN is checked against the specified hostname. If no
SAN is present in the server certificate, the usual check
against the certificate DN is used. If a SAN is present
but doesn't match the specified hostname, the session is
immediately terminated. This setting may be preferred
when a mix of certs with and without SANs are in use.
demand | hard
These keywords are equivalent. The SAN is checked against
the specified hostname. If no SAN is present in the
server certificate, or no SANs match, the session is
immediately terminated. This setting should be used when
only certificates with SANs are in use.
TLS_CRLCHECK <level>
Specifies if the Certificate Revocation List (CRL) of the CA
should be used to verify if the server certificates have not
been revoked. This requires TLS_CACERTDIR parameter to be set.
This parameter is ignored with GnuTLS. <level> can be specified
as one of the following keywords:
none No CRL checks are performed
peer Check the CRL of the peer certificate
all Check the CRL for a whole certificate chain
TLS_CRLFILE <filename>
Specifies the file containing a Certificate Revocation List to
be used to verify if the server certificates have not been
revoked. This parameter is only supported with GnuTLS.
ENVIRONMENT VARIABLES
LDAPNOINIT
disable all defaulting
LDAPCONF
path of a configuration file
LDAPRC basename of ldaprc file in $HOME or $CWD
LDAP<option-name>
Set <option-name> as from ldap.conf
FILES
/opt/local/etc/openldap/ldap.conf
system-wide ldap configuration file
$HOME/ldaprc, $HOME/.ldaprc
user ldap configuration file
$CWD/ldaprc
local ldap configuration file
SEE ALSO
ldap(3), ldap_set_option(3), ldap_result(3), openssl(1), sasl(3)
AUTHOR
Kurt Zeilenga, The OpenLDAP Project
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.
OpenLDAP 2.6.10 2025/05/22 ldap.conf(5)
openldap 2.6.10 - Generated Sun May 25 11:06:24 CDT 2025