ldap.conf(5) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | SYNTAX | OPTIONS | SASL OPTIONS | GSSAPI OPTIONS | TLS OPTIONS | ENVIRONMENT VARIABLES | FILES | SEE ALSO | AUTHOR | ACKNOWLEDGEMENTS | COLOPHON

LDAP.CONF(5)               File Formats Manual               LDAP.CONF(5)

NAME         top

       ldap.conf, .ldaprc - LDAP configuration file/environment variables

SYNOPSIS         top

       ETCDIR/ldap.conf, ldaprc, .ldaprc, $LDAP<option-name>

DESCRIPTION         top

       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  ETCDIR/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         top

       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         top

       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         top

       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         top

       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         top

       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         top

       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         top

       ETCDIR/ldap.conf
              system-wide ldap configuration file

       $HOME/ldaprc, $HOME/.ldaprc
              user ldap configuration file

       $CWD/ldaprc
              local ldap configuration file

SEE ALSO         top

       ldap(3), ldap_set_option(3), ldap_result(3), openssl(1), sasl(3)

AUTHOR         top

       Kurt Zeilenga, The OpenLDAP Project

ACKNOWLEDGEMENTS         top

       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.

COLOPHON         top

       This page is part of the OpenLDAP (an open source implementation
       of the Lightweight Directory Access Protocol) project.
       Information about the project can be found at 
       ⟨http://www.openldap.org/⟩.  If you have a bug report for this
       manual page, see ⟨http://www.openldap.org/its/⟩.  This page was
       obtained from the project's upstream Git repository
       ⟨https://git.openldap.org/openldap/openldap.git⟩ on 2025-02-02.
       (At that time, the date of the most recent commit that was found
       in the repository was 2025-01-06.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there is
       a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to
       man-pages@man7.org

OpenLDAP LDVERSION             RELEASEDATE                   LDAP.CONF(5)

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