# $OpenLDAP$
# Copyright 2007-2026 The OpenLDAP Foundation, All Rights Reserved.
# COPYING RESTRICTIONS APPLY, see COPYRIGHT.

H1: Common errors encountered when using OpenLDAP Software

The following sections attempt to summarize the most common causes of LDAP errors 
when using OpenLDAP

H2: Common causes of LDAP errors

H3: ldap_*: Can't contact LDAP server

The {{B:Can't contact LDAP server}} error is usually returned when the LDAP 
server cannot be contacted. This may occur for many reasons:

* the LDAP server is not running; this can be checked by running, for example,

>      telnet <host> <port>

replacing {{<host>}} and {{<port>}} with the hostname and the port the server 
is supposed to listen on.
* the client has not been instructed to contact a running server; with OpenLDAP 
command-line tools this is accomplished by providing the -H switch, whose 
argument is a valid LDAP url corresponding to the interface the server is 
supposed to be listening on.

H3: ldap_*: No such object

The {{B:no such object}} error is generally returned when the target DN of the 
operation cannot be located. This section details reasons common to all 
operations. You should also look for answers specific to the operation 
(as indicated in the error message).

The most common reason for this error is non-existence of the named object. First, 
check for typos.

Also note that, by default, a new directory server holds no objects 
(except for a few system entries). So, if you are setting up a new directory 
server and get this message, it may simply be that you have yet to add the 
object you are trying to locate.

The error commonly occurs because a DN was not specified and a default was not 
properly configured.

If you have a suffix specified in slapd.conf eg.

>      suffix "dc=example,dc=com"

You should use

>      ldapsearch -b 'dc=example,dc=com' '(cn=jane*)'

to tell it where to start the search.

The {{F:-b}} should be specified for all LDAP commands unless you have an 
{{ldap.conf}}(5) default configured.

See {{ldapsearch}}(1), {{ldapmodify}}(1) 

Also, {{slapadd}}(8) and its ancillary programs are very strict about the 
syntax of the LDIF file. 

Some liberties in the LDIF file may result in an apparently successful creation 
of the database, but accessing some parts of it may be difficult.

One known common error in database creation is putting a blank line before the 
first entry in the LDIF file. {{B:There must be no leading blank lines in the 
LDIF file.}}

It is generally recommended that {{ldapadd}}(1) be used instead of {{slapadd}}(8) 
when adding new entries your directory. {{slapadd}}(8) should be used to bulk 
load entries known to be valid.

Another cause of this message is a referral 
({SECT:Constructing a Distributed Directory Service}}) entry to an unpopulated 
directory. 

Either remove the referral, or add a single record with the referral base DN 
to the empty directory.

This error may also occur when slapd is unable to access the contents of its 
database because of file permission problems. For instance, on a Red Hat Linux 
system, slapd runs as user 'ldap'. When slapadd is run as root to create a 
database from scratch, the contents of {{F:/var/lib/ldap}} are created with 
user and group root and with permission 600, making the contents inaccessible 
to the slapd server.

H3: ldap_*: Can't chase referral

This is caused by the line

>      referral        ldap://root.openldap.org

In {{F:slapd.conf}}, it was provided as an example for how to use referrals 
in the original file. However if your machine is not permanently connected to 
the Internet, it will fail to find the server, and hence produce an error message.

To resolve, just place a # in front of line and restart slapd or point it to 
an available ldap server.

See also: {{ldapadd}}(1), {{ldapmodify}}(1) and {{slapd.conf}}(5)

H3: ldap_*: server is unwilling to perform

slapd will return an unwilling to perform error if the backend holding the 
target entry does not support the given operation.

The password backend is only willing to perform searches. It will return an 
unwilling to perform error for all other operations.

H3: ldap_*: Insufficient access

This error occurs when server denies the operation due to insufficient access. 
This is usually caused by binding to a DN with insufficient privileges 
(or binding anonymously) to perform the operation. 

You can bind as the rootdn/rootpw specified in {{slapd.conf}}(5) to gain full 
access. Otherwise, you must bind to an entry which has been granted the 
appropriate rights through access controls.


H3: ldap_*: Invalid DN syntax

The target (or other) DN of the operation is invalid. This implies that either 
the string representation of the DN is not in the required form, one of the 
types in the attribute value assertions is not defined, or one of the values 
in the attribute value assertions does not conform to the appropriate syntax.

H3: ldap_*: Referral hop limit exceeded

This error generally occurs when the client chases a referral which refers 
itself back to a server it already contacted. The server responds as it did 
before and the client loops. This loop is detected when the hop limit is exceeded.

This is most often caused through misconfiguration of the server's default 
referral. The default referral should not be itself:

That is, on {{F:ldap://myldap/}} the default referral should not be {{F:ldap://myldap/}}
 (or any hostname/ip which is equivalent to myldap).

H3: ldap_*: operations error

In some versions of {{slapd}}(8), {{operationsError}} was returned instead of other.

H3: ldap_*: other error

The other result code indicates an internal error has occurred. 
While the additional information provided with the result code might provide 
some hint as to the problem, often one will need to consult the server's log files.

H3: ldap_add/modify: Invalid syntax

This error is reported when a value of an attribute does not conform to syntax 
restrictions. Additional information is commonly provided stating which value 
of which attribute was found to be invalid. Double check this value and other 
values (the server will only report the first error it finds).

Common causes include:

* extraneous whitespace (especially trailing whitespace)
* improperly encoded characters (LDAPv3 uses UTF-8 encoded Unicode)
* empty values (few syntaxes allow empty values)


For certain syntax, like OBJECT IDENTIFIER (OID), this error can indicate that 
the OID descriptor (a "short name") provided is unrecognized. For instance, 
this error is returned if the {{objectClass}} value provided is unrecognized.

H3: ldap_add/modify: Object class violation

This error is returned with the entry to be added or the entry as modified 
violates the object class schema rules. Normally additional information is 
returned the error detailing the violation. Some of these are detailed below.

Violations related to the entry's attributes:

>      Attribute not allowed

A provided attribute is not allowed by the entry's object class(es). 

>      Missing required attribute

An attribute required by the entry's object class(es) was not provided. 

Violations related to the entry's class(es):

>      Entry has no objectClass attribute

The entry did not state which object classes it belonged to. 

>      Unrecognized objectClass

One (or more) of the listed objectClass values is not recognized. 

>      No structural object class provided

None of the listed objectClass values is structural. 

>      Invalid structural object class chain

Two or more structural objectClass values are not in same structural object 
class chain. 

>      Structural object class modification

Modify operation attempts to change the structural class of the entry. 

>      Instantiation of abstract objectClass.

An abstract class is not subordinate to any listed structural or auxiliary class. 

>      Invalid structural object class

Other structural object class problem. 

>      No structuralObjectClass operational attribute

This is commonly returned when a shadow server is provided an entry which does 
not contain the structuralObjectClass operational attribute. 


Note that the above error messages as well as the above answer assumes basic 
knowledge of LDAP/X.500 schema.

H3: ldap_add: No such object

The "ldap_add: No such object" error is commonly returned if parent of the 
entry being added does not exist. Add the parent entry first...

For example, if you are adding "cn=bob,dc=domain,dc=com" and you get:

>      ldap_add: No such object

The entry "dc=domain,dc=com" likely doesn't exist. You can use ldapsearch to 
see if does exist:

>      ldapsearch -b 'dc=domain,dc=com' -s base '(objectclass=*)'

If it doesn't, add it. See {{SECT:A Quick-Start Guide}} for assistance.

Note: if the entry being added is the same as database suffix, it's parent 
isn't required. i.e.: if your suffix is "dc=domain,dc=com", "dc=com" doesn't 
need to exist to add "dc=domain,dc=com".

This error will also occur if you try to add any entry that the server is not 
configured to hold.

For example, if your database suffix is "dc=domain,dc=com" and you attempt to 
add "dc=domain2,dc=com", "dc=com", "dc=domain,dc=org", "o=domain,c=us", or an 
other DN in the "dc=domain,dc=com" subtree, the server will return a
 "No such object" (or referral) error.

{{slapd}}(8) will generally return "no global superior knowledge" as additional 
information indicating its return noSuchObject instead of a referral as the 
server is not configured with knowledge of a global superior server.


H3: ldap add: invalid structural object class chain

This particular error refers to the rule about STRUCTURAL objectclasses, which 
states that an object is of one STRUCTURAL class, the structural class of the 
object. The object is said to belong to this class, zero or more auxiliaries
 classes, and their super classes. 

While all of these classes are commonly listed in the objectClass attribute of 
the entry, one of these classes is the structural object class of the entry. 
Thus, it is OK for an objectClass attribute 
to contain inetOrgPerson, organizationalPerson, and person because they inherit
 one from another to form a single super class chain. That is, inetOrgPerson SUPs 
organizationPerson SUPs person. On the other hand, it is invalid for both inetOrgPerson 
and account to be listed in objectClass as inetOrgPerson and account are not 
part of the same super class chain (unless some other class is also listed 
with is a subclass of both).

To resolve this problem, one must determine which class will better serve 
structural object class for the entry, adding this class to the objectClass 
attribute (if not already present), and remove any other structural class from 
the entry's objectClass attribute which is not a super class of the structural 
object class.

Which object class is better depends on the particulars of the situation. 
One generally should consult the documentation for the applications one is 
using for help in making the determination.

H3: ldap_add: no structuralObjectClass operational attribute

ldapadd(1) may error:

>      adding new entry "uid=XXX,ou=People,o=campus,c=ru"
>        ldap_add: Internal (implementation specific) error (80)
>           additional info: no structuralObjectClass operational attribute

when slapd(8) cannot determine, based upon the contents of the objectClass 
attribute, what the structural class of the object should be.


H3: ldap_add/modify/rename: Naming violation

OpenLDAP's slapd checks for naming attributes and distinguished values consistency, 
according to RFC 4512.

Naming attributes are those attributeTypes that appear in an entry's RDN;
 distinguished values are the values of the naming attributes that appear in 
an entry's RDN, e.g, in

>      cn=Someone+mail=someone@example.com,dc=example,dc=com

the naming attributes are cn and mail, and the distinguished values are 
Someone and someone@example.com.

OpenLDAP's slapd checks for consistency when:

* adding an entry
* modifying an entry, if the values of the naming attributes are changed
* renaming an entry, if the RDN of the entry changes

Possible causes of error are:

* the naming attributes are not present in the entry; for example:

>                dn: dc=example,dc=com
>                objectClass: organization
>                o: Example
>                # note: "dc: example" is missing

* the naming attributes are present in the entry, but in the attributeType 
definition they are marked as:
- collective
- operational
- obsolete

* the naming attributes are present in the entry, but the distinguished values 
are not; for example:

>                dn: dc=example,dc=com
>                objectClass: domain
>                dc: foobar
>                # note: "dc" is present, but the value is not "example"

* the naming attributes are present in the entry, with the distinguished values, but the naming attributes:
- do not have an equality field, so equality cannot be asserted
- the matching rule is not supported (yet)
- the matching rule is not appropriate

* the given distinguished values do not comply with their syntax

* other errors occurred during the validation/normalization/match process; 
this is a catchall: look at previous logs for details in case none of the above 
apply to your case.

In any case, make sure that the attributeType definition for the naming attributes 
contains an appropriate EQUALITY field; or that of the superior, if they are 
defined based on a superior attributeType (look at the SUP field). See RFC 4512 for details.


H3: ldap_add/delete/modify/rename: no global superior knowledge

If the target entry name places is not within any of the databases the server 
is configured to hold and the server has no knowledge of a global superior, 
the server will indicate it is unwilling to perform the operation and provide 
the text "no global superior knowledge" as additional text.

Likely the entry name is incorrect, or the server is not properly configured 
to hold the named entry, or, in distributed directory environments, a default 
referral was not configured.


H3: ldap_bind: Insufficient access

Current versions of slapd(8) requires that clients have authentication 
permission to attribute types used for authentication purposes before accessing 
them to perform the bind operation. As all bind operations are done anonymously 
(regardless of previous bind success), the auth access must be granted to anonymous.

In the example ACL below grants the following access:

* to anonymous users:
- permission to authenticate using values of userPassword
* to authenticated users:
- permission to update (but not read) their userPassword
- permission to read any object excepting values of userPassword 

All other access is denied.

>        access to attr=userPassword
>          by self =w
>          by anonymous auth

>        access *
>          by self write
>          by users read


H3: ldap_bind: Invalid credentials

The error usually occurs when the credentials (password) provided does not 
match the userPassword held in entry you are binding to.

The error can also occur when the bind DN specified is not known to the server.

Check both! In addition to the cases mentioned above you should check if the 
server denied access to userPassword on selected parts of the directory. In 
fact, slapd always returns "Invalid credentials" in case of failed bind, 
regardless of the failure reason, since other return codes could reveal the 
validity of the user's name.

To debug access rules defined in slapd.conf, add "ACL" to log level.

H3: ldap_bind: Protocol error

There error is generally occurs when the LDAP version requested by the 
client is not supported by the server.

The OpenLDAP Software 2.x server, by default, only accepts version 3 LDAP Bind 
requests but can be configured to accept a version 2 LDAP Bind request. 

Note: The 2.x server expects LDAPv3 [RFC4510] to be used when the client 
requests version 3 and expects a limited LDAPv3 variant (basically, LDAPv3 
syntax and semantics in an LDAPv2 PDUs) to be used when version 2 is expected. 

This variant is also sometimes referred to as LDAPv2+, but differs from the U-Mich 
LDAP variant in a number of ways.

H3: ldap_modify: cannot modify object class

This message is commonly returned when attempting to modify the objectClass 
attribute in a manner inconsistent with the LDAP/X.500 information model. In 
particular, it commonly occurs when one tries to change the structure of the 
object from one class to another, for instance, trying to change an 'apple' 
into a 'pear' or a 'fruit' into a 'pear'. 

Such changes are disallowed by the slapd(8) in accordance with LDAP and X.500 restrictions.


H3: ldap_sasl_interactive_bind_s: ...

If you intended to bind using a DN and password and get an error from 
ldap_sasl_interactive_bind_s, you likely forgot to provide a '-x' option to 
the command. By default, SASL authentication is used. '-x' is necessary to 
select "simple" authentication.


H3: ldap_sasl_interactive_bind_s: No such Object

This indicates that LDAP SASL authentication function could not read the 
Root DSE.
The error will occur when the server doesn't provide a root DSE. This may be 
due to access controls.


H3: ldap_sasl_interactive_bind_s: No such attribute

This indicates that LDAP SASL authentication function could read the Root 
DSE but it contained no supportedSASLMechanism attribute.

The supportedSASLmechanism attribute lists mechanisms currently available. 
The list may be empty because none of the supported mechanisms are currently 
available. For example, EXTERNAL is listed only if the client has established 
its identity by authenticating at a lower level (e.g. TLS).

Note: the attribute may not be visible due to access controls

Note: SASL bind is the default for all OpenLDAP tools, e.g. ldapsearch(1), ldapmodify(1). To force use of "simple" bind, use the "-x" option. Use of "simple" bind is not recommended unless one has adequate confidentiality protection in place (e.g. TLS/SSL, IPSEC).

H3: ldap_sasl_interactive_bind_s: Unknown authentication method

This indicates that none of the SASL authentication supported by the server 
are supported by the client, or that they are too weak or otherwise inappropriate 
for use by the client. Note that the default security options disallows the use 
of certain mechanisms such as ANONYMOUS and PLAIN (without TLS).

Note: SASL bind is the default for all OpenLDAP tools. To force use of "simple" bind, use the "-x" option. Use of "simple" bind is not recommended unless one has adequate confidentiality protection in place (e.g. TLS/SSL, IPSEC).

H3: ldap_sasl_interactive_bind_s: Local error (82)

Apparently not having forward and reverse DNS entries for the LDAP server can result in this error.


H3: ldap_search: Partial results and referral received

This error is returned with the server responses to an LDAPv2 search query 
with both results (zero or more matched entries) and references (referrals to other servers).
See also: ldapsearch(1).

If the updatedn on the replica does not exist, a referral will be returned. 
It may do this as well if the ACL needs tweaking.

H3: ldap_start_tls: Operations error

ldapsearch(1) and other tools will return

>        ldap_start_tls: Operations error (1)
>              additional info: TLS already started

When the user (though command line options and/or ldap.conf(5)) has requested 
TLS (SSL) be started twice. For instance, when specifying both "-H ldaps://server.do.main" and "-ZZ".

H2: Other Errors

H3: ber_get_next on fd X failed errno=34 (Numerical result out of range)

This slapd error generally indicates that the client sent a message that 
exceeded an administrative limit. See sockbuf_max_incoming and sockbuf_max_incoming_auth 
configuration directives in slapd.conf(5).

H3: ber_get_next on fd X failed errno=11 (Resource temporarily unavailable)

This message is not indicative of abnormal behavior or error. It simply means 
that expected data is not yet available from the resource, in this context, a 
network socket. slapd(8) will process the data once it does becomes available.

H3: daemon: socket() failed errno=97 (Address family not supported)

This message indicates that the operating system does not support one of the 
(protocol) address families which slapd(8) was configured to support. Most 
commonly, this occurs when slapd(8) was configured to support IPv6 yet the 
operating system kernel wasn't. In such cases, the message can be ignored.

H3: GSSAPI: gss_acquire_cred: Miscellaneous failure; Permission denied;

This message means that slapd is not running as root and, thus, it cannot get 
its Kerberos 5 key from the keytab, usually file /etc/krb5.keytab.

A keytab file is used to store keys that are to be used by services or daemons 
that are started at boot time. It is very important that these secrets are kept 
beyond reach of intruders.

That's why the default keytab file is owned by root and protected from being 
read by others. Do not mess with these permissions, build a different keytab 
file for slapd instead, and make sure it is owned by the user that slapd
runs as.

To do this, start kadmin, and enter the following commands:

>     addprinc -randkey ldap/ldap.example.com@EXAMPLE.COM
>     ktadd -k /etc/openldap/ldap.keytab ldap/ldap.example.com@EXAMPLE.COM 

Then, on the shell, do:

>     chown ldap:ldap /etc/openldap/ldap.keytab
>     chmod 600 /etc/openldap/ldap.keytab 

Now you have to tell slapd (well, actually tell the gssapi library in Kerberos 5 
that is invoked by Cyrus SASL) where to find the new keytab. You do this by 
setting the environment variable KRB5_KTNAME like this:

>     export KRB5_KTNAME="FILE:/etc/openldap/ldap.keytab"

Set that environment variable on the slapd start script (Red Hat users might 
find /etc/sysconfig/ldap a perfect place).

This only works if you are using MIT kerberos. It doesn't work with Heimdal, 
for instance.


In Heimdal there is a function gsskrb5_register_acceptor_identity() that sets 
the path of the keytab file you want to use. In Cyrus SASL 2 you can add

>    keytab: /path/to/file

to your application's SASL config file to use this feature. This only works with Heimdal.


H3: access from unknown denied

This related to TCP wrappers. See hosts_access(5) for more information.
in the log file: "access from unknown denied" This related to TCP wrappers. 
See hosts_access(5) for more information.
for example: add the line "slapd: .hosts.you.want.to.allow" in /etc/hosts.allow 
to get rid of the error.

H3: ldap_read: want=# error=Resource temporarily unavailable

This message occurs normally. It means that pending data is not yet available 
from the resource, a network socket. slapd(8) will process the data once it 
becomes available.

H3: `make test' fails

Some times, `make test' fails at the very first test with an obscure message like

>    make test
>    make[1]: Entering directory `/ldap_files/openldap-2.5.0/tests'
>    make[2]: Entering directory `/ldap_files/openldap-2.5.0/tests'
>    Initiating LDAP tests for MDB...
>    Cleaning up test run directory leftover from previous run.
>     Running ./scripts/all...
>    >>>>> Executing all LDAP tests for mdb
>    >>>>> Starting test000-rootdse ...
>    running defines.sh
>    Starting slapd on TCP/IP port 9011...
>    Using ldapsearch to retrieve the root DSE...
>    Waiting 5 seconds for slapd to start...
>    ./scripts/test000-rootdse: line 40: 10607 Segmentation fault $SLAPD -f $CONF1 -h $URI1 -d $LVL $TIMING >$LOG1 2>&1
>    Waiting 5 seconds for slapd to start...
>    Waiting 5 seconds for slapd to start...
>    Waiting 5 seconds for slapd to start...
>    Waiting 5 seconds for slapd to start...
>    Waiting 5 seconds for slapd to start...
>    ./scripts/test000-rootdse: kill: (10607) - No such pid
>    ldap_sasl_bind_s: Can't contact LDAP server (-1)
>    >>>>> Test failed
>    >>>>> ./scripts/test000-rootdse failed (exit 1)
>    make[2]: *** [mdb-yes] Error 1
>    make[2]: Leaving directory `/ldap_files/openldap-2.5.0/tests'
>    make[1]: *** [test] Error 2
>    make[1]: Leaving directory `/ldap_files/openldap-2.5.0/tests'
>    make: *** [test] Error 2

or so. Usually, the five lines

    Waiting 5 seconds for slapd to start...

indicate that slapd didn't start at all.

In tests/testrun/slapd.1.log there is a full log of what slapd wrote while 
trying to start. The log level can be increased by setting the environment 
variable SLAPD_DEBUG to the corresponding value; see loglevel in slapd.conf(5) 
for the meaning of log levels.

A typical reason for this behavior is a runtime link problem, i.e. slapd cannot 
find some dynamic libraries it was linked against. Try running ldd(1) on slapd 
(for those architectures that support runtime linking).

There might well be other reasons; the contents of the log file should help 
clarifying them.

Tests that fire up multiple instances of slapd typically log to tests/testrun/slapd.<n>.log, 
with a distinct <n> for each instance of slapd; list tests/testrun/ for possible 
values of <n>.

H3: ldap_*: Internal (implementation specific) error (80) - additional info: entry index delete failed

This seems to be related with wrong ownership of the MDB's dir (/var/lib/ldap)
and files. The files must be owned by the user that slapd runs as.

>    chown -R ldap:ldap /var/lib/ldap 

fixes it in Debian


H3: ldap_sasl_interactive_bind_s: Can't contact LDAP server (-1)

Using SASL, when a client contacts LDAP server, the slapd service dies 
immediately and client gets an error :

>     SASL/GSSAPI authentication started ldap_sasl_interactive_bind_s: Can't contact LDAP server (-1)

Then check the slapd service, it stopped.
