WDIFF

draft-ietf-asid-ldapv3-protocol-03.txt --> draft-ietf-asid-ldapv3-protocol-04.txt

Network Working Group M. Wahl
INTERNET-DRAFT Critical Angle Inc.
Replaces: RFC 1777, RFC 1798 1777 T. Howes
Netscape Communications Corp.
S. Kille
ISODE Consortium
Isode Limited
Expires in six months from 22 October 1996 25 March 1997
Intended Category: Standards Track

Lightweight Directory Access Protocol (v3)
<draft-ietf-asid-ldapv3-protocol-03.txt>
<draft-ietf-asid-ldapv3-protocol-04.txt>

Table of Contents - see end of document.

1. Status of this Memo

This document is an Internet-Draft. Internet-Drafts are working
documents of the Internet Engineering Task Force (IETF), its areas, and
its working groups. Note that other groups may also distribute working
documents as Internet-Drafts.

Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference material
or to cite them other than as "work in progress."

To learn the current status of any Internet-Draft, please check the
"1id-abstracts.txt" listing contained in the Internet-Drafts Shadow
Directories on ds.internic.net (US East Coast), nic.nordu.net (Europe),
ftp.isi.edu (US West Coast), or munnari.oz.au (Pacific Rim).

2. Abstract

The protocol described in this document is designed to provide access
to directories supporting the X.500 models, while not incurring the
resource requirements of the X.500 Directory Access Protocol (DAP). This
protocol is specifically targeted at management applications and browser
applications that provide read/write interactive access to directories.
When used with a directory supporting the X.500 protocols, it is
intended to be a complement to the X.500 DAP.

Key aspects of this version of LDAP are:

- All protocol elements of LDAP LDAPv2 (RFC 1777) and CLDAP (RFC 1798) are supported.

- Protocol elements are The protocol
is carried directly over TCP or other transport, bypassing
much of the session/presentation overhead. Connectionless
transport (UDP) is also supported for efficient lookup operations. overhead of X.500 DAP.

- Most protocol data elements can be encoded as ordinary strings
(e.g., Distinguished Names).

- Referrals to other servers may be returned.

- SASL and SSL mechanisms may be used with LDAP to provide connection
security services.

Wahl, Howes & Howes, Kille [Page 1] Page 1

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996 March 1997

- New features Attribute values and Distinguished Names have been added, such as internationalized
through the abilities to retrieve
attribute values in binary or search results in pages.

- Important features use of X.500(1993) and X.500(1997) are included.

- Referrals to other servers can be returned. the ISO 10646 character set.

- The protocol can be extended to support bilaterally-defined new operations, and controls
may be used to extend existing operations.

- Several session controls Schema may be requested by published in the client. directory for use by clients.

3. Models

Interest in X.500 [1] directory technologies in the Internet has lead led to
efforts to reduce the high "cost cost of entry" entry associated with use of these
technologies. This document continues the efforts to define directory
protocol alternatives: it updates alternatives, updating the LDAP [2] protocol specification,
adding support for new features, including some support for connecting
to X.500 services that implement the 1993 or 1997 edition protocols. specification.

3.1. Protocol Model

The general model adopted by this protocol is one of clients
performing protocol operations against servers. In this model, a
client transmits a protocol request describing the operation to be
performed to a server, which server. The server is then responsible for performing
the necessary operation(s) in the directory. Upon completion of
the operation(s), the server returns a response containing any results
or errors to the requesting client.

In keeping with the goal of easing the costs associated with use of
the directory, it is an objective of this protocol to minimize the
complexity of clients so as to facilitate widespread deployment of
applications capable of utilizing using the directory.

Note that, that although servers are required to return responses whenever
such responses are defined in the protocol, there is no requirement
for synchronous behavior on the part of either clients or servers.
Requests and responses for multiple operations may be exchanged
between a client and server in any order, provided the client
eventually receives a response for every request that requires one.

In LDAP versions 1 and 2, no provision was made for protocol servers
returning referrals to clients. However, for improved performance and
distribution this version of the protocol permits servers to return to
clients referrals to other servers if requested. servers. This allows servers,
if requested by clients, servers to offload the
work of contacting other servers to progress operations.

Clients may also request that no referrals be returned, in which case
the server must ensure that the operation is performed against the
directory, or else return an error. This is the default.

Wahl, Howes & Kille [Page 2]

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

Note that this the core protocol operations defined in this document can be
mapped to a strict subset of the X.500(1997) directory abstract service,
so it can be cleanly provided by the DAP. However there is not a
one-to-one mapping between LDAP protocol operations and DAP operations:
server implementations acting as a gateway to X.500 directories may need
to make multiple DAP
requests to perform extended operations. requests.

3.2. Data Model

This section provides a brief introduction to the X.500 data model, as
used by LDAP.

Wahl, Howes, Kille Page 2

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) March 1997

The LDAP protocol assumes there are one or more servers which jointly
provide access to a Directory Information Tree (DIT). The tree is made
up of entries. Entries have names: one or more attribute values from the
entry itself form its relative distinguished name (RDN), which must MUST be unique
among all its siblings. The concatenation of the relative distinguished
names of the line sequence of entries from a particular entry to an immediate
subordinate of the root of the tree forms that entry's Distinguished
Name (DN), which is unique in the tree. An example of a Distinguished
Name is

CN=Steve Kille, O=ISODE Consortium, O=Isode Limited, C=GB

Some servers may hold cache or shadow copies of entries, which can be
used to answer search and comparison queries, but will return referrals
or contact other servers if modification operations are requested.

Servers which perform caching or shadowing MUST ensure that they do not
violate any access control constraints placed on the data by the
originating server.

The largest collection of entries, starting at an entry that is mastered by
a particular server, and including all its subordinates and their
subordinates, down to an entry which is the entries which are mastered by a different server, servers,
is termed a naming context. For example, in the following sample DIT, one server
might master only the entry C=GB, and another server master both the
entries O=Foo,C=US and O=Bar,C=US. Each of these entries are in a separate
naming context. The root of the DIT is not an entry a DSA-specific Entry
(DSE) and not part of any naming context.

(ROOT)
|
C=GB
/------------/ \--------------\
O=Foo O=Bar

3.2.1 context: each server has different
attribute values in the root DSE.

3.2.1. Attributes of Entries

Entries consist of a set of attributes. An attribute is a type with
one or more associated values. The attribute type, type is identified by a
short descriptive name and an OID (object identifier), identifier). The attribute
type governs the maximum number of values permissible for an attribute of
that type in an entry, the syntax to which the values must conform, the types
kinds of matching which can be performed on values of that attribute, and
other functions.

Wahl, Howes & Kille [Page 3]

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

An example of an attribute is "mail". There may be one or more values
of this attribute, they must be IA5 strings, and they are case
insensitive (e.g. "foo@bar.com" will match "FOO@BAR.COM").

Each entry must MUST have an objectClass attribute. The objectClass
attribute specifies the object classes of an entry, which along with
the system and user schema determine the permitted attributes of an entry.
Values of this attribute may be modified by clients, but the objectClass
attribute cannot be removed. Servers may restrict the modifications of
this attribute to prevent the basic structural class of the entry from
being changed (e.g. one cannot change a person into a country).

A small number of

Wahl, Howes, Kille Page 3

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) March 1997

Some attributes, termed operational attributes, are used by servers for
administering the directory system itself. They are not returned in
search results unless they were explicitly requested by name. Attributes which
are not operational, such as "mail", will have their schema and syntax
constraints enforced by servers, but servers will generally not make use
of their values.

Servers must not MUST NOT permit clients to add attributes to an entry unless
those attributes are permitted by the object class definitions, the
schema controlling that entry (specified in the subschema subentry - see
below), or are operational attributes known to that server and used for
administrative purposes. Note that there is a particular objectClass
'extensibleObject' defined in [5] which permits all user attributes
to be present in an entry.

Entries may contain, among others, the following operational attributes,
defined in [5]. These attributes are maintained automatically by the
server and are not modifiable by clients:

- creatorsName: the Distinguished Name of the user who added this entry
to the directory.

- createTimestamp: the time this entry was added to the directory.

- modifiersName: the Distinguished Name of the user who last modified
this entry.

- modifyTimestamp: the time this entry was last modified.

- subschemaSubentry: the Distinguished Name of the subschema subentry entry
which controls the schema for this entry.
- entryName: the Distinguished Name of the entry.

Servers may implement other operational attributes. Servers which
also make use of X.500(1993) protocols will provide support for more of
the attributes defined in X.501, including administrativeRole and dseType.
Some servers may permit the retrieval of subschema attributes directly
from user entries.

3.2.2

3.2.2. Subschema Subentry

A subentry is a special kind of entry which is used by servers and holds
attributes for administering the directory system. Subentries are defined
in clause 11.6 of X.501 [6]. Entries

Subschema subentries entries are used for administering information about the
directory schema, in particular the object classes and attribute types
supported by directory servers.

Wahl, Howes & Kille [Page 4]

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996 A server may provide access to one or more single subschema subentries to
permit clients to interrogate the entry contains
all schema which is in force for definitions used by entries in a particular part of the directory.
directory tree.

A server which masters entries and permits clients to modify these
entries must MUST implement and provide access to these subschema subentries, entries,
so that its clients may discover the attributes and object classes which
are permitted to be present. It is strongly recommended that all other
servers implement subschema subentries this as well.

The following four attributes, defined in [6] with string representations
in [5], must attributes MUST be present in all subschema subentries: entries:

- CN: cn: this attribute must MUST be used to form the RDN of the subschema
subentry.
entry.

- objectClass: the attribute must MUST have at least the values "top" and
"subschema".

Wahl, Howes, Kille Page 4

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) March 1997

- objectClasses: each value of this attribute specifies an object class
known to the server.

- attributeTypes: each value of this attribute specifies an attribute
type known to the server.

These are defined in [5]. Other operational attributes may be present in subschema subentries,
in particular dseType, subtreeSpecification, ditStructureRules, nameForms,
ditContentRules,
entries, to reflect additional supported capabilities. These include
matchingRules, matchingRuleUse, createTimestamp,
creatorsName, modifyTimestamp, modifiersName, entryName, as described dITStructureRules, dITContentRules
and nameForms.

Servers SHOULD provide the attributes createTimestamp and modifyTimestamp
in
[6]. subschema entries, in order to allow clients to maintain their caches of
schema information.

Servers which follow X.500(93) models may implement subschema using the
X.500 subschema mechanisms. LDAP clients MUST NOT assume that servers
implement any of the other aspects of X.500 subschema.

Clients must MUST only retrieve these attributes from a subentry subschema entry by requesting
them by name in
a baseObject base object search of the subentry. entry, where the search filter is
"(objectClass=subschema)". (This will allow LDAPv3 servers which gateway
to X.500 to detect that subentry information is being requested.)

3.3. Relationship to X.500

This document defines LDAP in terms of X.500 as an X.500 access
mechanism. An LDAP server must MUST act in accordance with the
X.500(1993) series of ITU Recommendations recommendations when providing the service.
However, it is not required that an LDAP server make use of any X.500
protocols in providing this service, e.g. LDAP can be mapped onto any
other directory system so long as the X.500 data and service model as
used in LDAP is not violated in the LDAP interface.

3.4. Server-specific Data Requirements

An LDAP server must MUST provide information about itself and other
information that is specific to each server. This is represented as a
number of attributes located in the root DSE (DSA-Specific Entry),
which is named with the zero-length LDAPDN. These attributes
are retrievable if a client performs a base object search of the
root,
root with filter "(objectClass=*)", however they are subject to
access control restrictions.
They must not

The root DSE MUST NOT be included if the client performs a subtree search
starting from the root.

Servers in general will not may allow clients to modify these attributes.

Wahl, Howes & Kille [Page 5]

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

The following attributes of the root DSE are defined in section 5.1.3 of
[5]. Additional attributes may be defined in later documents.

- administratorAddress: a URL containing address of administrator.
- currentTime: the current time.
- serverName: the Distinguished Name of the server.
- certificationPath: the server's certificate path.
- namingContexts: naming contexts held in the server. Naming contexts
are defined in section 17 of X.501 [6].

- subschemaSubentry: subschema subentries known by this server.

Wahl, Howes, Kille Page 5

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) March 1997

- altServer: alternative servers in case this one is later unavailable.

- supportedExtension: list of supported extended operations.

- supportedControl: list of supported session controls.

- supportedSASLMechanisms: list of supported SASL security features.

- supportedLDAPVersion: LDAP versions implemented by the server.

If the server does not master or shadow entries and does not know the locations of
schema information, the subschemaSubentry attribute must is not be present
in the root DSE. If the server holds master or shadow
copies of masters directory entries under one or
more schema rules, there may be any number of values of the
subschemaSubentry attribute in the root DSE.

4. Elements of Protocol

The LDAP protocol is described using Abstract Syntax Notation 1 [3]. It (ASN.1) [3],
and is typically transferred using a subset of the ASN.1 Basic Encoding Rules. Rules
[11]. In order to support future extensions to this protocol, clients and
servers must MUST ignore elements of SEQUENCEs whose tags they do not
recognize.

Note that unlike X.500, each change to the LDAP protocol other than through
the extension mechanisms will have a different version number. A client
will indicate the version it supports as part of the bind request,
described in section 4.1.2. 4.2. If a client has not sent a bind, the server
MUST assume that version 3 is supported in the client (since version 2
required that the client bind first).

Clients may determine the protocol version a server supports by reading
the supportedLDAPVersion attribute from the root DSE. Servers which
implement version 3 or later versions MUST provide this attribute.
Servers which only implement version 2 may not provide this attribute.

4.1. Common Elements

This section describes the LDAPMessage envelope PDU format, as well as
data type definitions which are used in the protocol operations.

4.1.1. Message Envelope

For the purposes of protocol exchanges, all protocol operations are
encapsulated in a common envelope, the LDAPMessage, which is defined
as follows:

Wahl, Howes & Howes, Kille [Page 6] Page 6

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996 March 1997

LDAPMessage ::= SEQUENCE {
messageID MessageID,
cldapUserName LDAPDN OPTIONAL,
protocolOp CHOICE {
bindRequest BindRequest,
bindResponse BindResponse,
unbindRequest UnbindRequest,
searchRequest SearchRequest,
searchResEntry SearchResultEntry,
searchResDone SearchResultDone,
searchResRef SearchResultReference,
searchResFull SearchResultFull,
modifyRequest ModifyRequest,
modifyResponse ModifyResponse,
addRequest AddRequest,
addResponse AddResponse,
delRequest DelRequest,
delResponse DelResponse,
modDNRequest ModifyDNRequest,
modDNResponse ModifyDNResponse,
compareRequest CompareRequest,
compareResponse CompareResponse,
abandonRequest AbandonRequest,
sessionRequest SessionRequest,
sessionResponse SessionResponse,
extendedReq ExtendedRequest,
extendedResp ExtendedResponse } },
controls [0] Controls OPTIONAL }

MessageID ::= INTEGER (0 .. maxInt)

maxInt INTEGER ::= 2147483647 -- (2^^31 - 1) --

The function of the LDAPMessage is to provide an envelope containing
common fields required in all protocol exchanges. At this time the
only common fields are the message ID and cldapUserName.

All LDAPMessage envelopes encapsulating responses contain the messageID
value of the controls.

If the server receives a PDU from the client in which the LDAPMessage
SEQUENCE tag cannot be recognized, the messageID cannot be parsed,
the tag of the protocolOp is not recognized as a request, or the
encoding structures or lengths of data fields are found to be incorrect,
then the server MUST return the notice of disconnection described in
section 4.4.1, with resultCode protocolError, and immediately close the
connection. In other cases that the server cannot parse the request
received by the client, the server MUST return an appropriate response to
the request, with the resultCode set to protocolError.

If the client receives a PDU from the server which cannot be parsed,
the client may discard the PDU, or may abruptly close the connection.

The ASN.1 type Controls is defined in section 4.1.12.

4.1.1.1. Message ID

All LDAPMessage envelopes encapsulating responses contain the messageID
value of the corresponding request LDAPMessage.

Wahl, Howes, Kille Page 7

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) March 1997

The message ID is required to of a request MUST have a value different from the values of
any other requests outstanding in the LDAP session of which this message
is a part.

A client must not MUST NOT send a second request with the same message ID as another an
earlier request on the same connection if the first request is outstanding.
If it does so, client has not received the
final response from the earlier request. Otherwise the behavior is
undefined. Typically a client will Typical clients increment a counter for each request.

For all requests except for search, unbind and abandon, the message ID is
outstanding until the client receives the response for that operation.

For a searchRequest which has not been abandoned, the message ID is
outstanding until the SearchResultDone for that search is received.

Wahl, Howes & Kille [Page 7]

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

A client must not MUST NOT reuse the message id of an abandonRequest or of the
abandoned operation until it has received a response from the server for
another request invoked subsequent to the abandonRequest, as the
abandonRequest itself does not have a response.

4.1.2. String Types

The cldapUserName identifies the requesting user for this message. It
is only present for backwards compatibility with RFC 1798, if this
LDAPMessage is carried in a connectionless transport protocol, such as UDP.
Its significance is equivalent to a bind with a zero-length password.
When the LDAP session is carried in a connection-oriented transport
protocol this field must be absent. LDAPv3 client implementors must not
use this field in connectionless requests, but instead concatenate a bind
request with the other operations in the request. Concatenation and
connectionless transport are described in section 5.1.3.

4.1.2. String Types

The LDAPString LDAPString is a notational convenience to indicate that, although
strings of LDAPString type encode as OCTET STRING types, the ISO 10646
[15]
[13] character set (a superset of Unicode) is used, encoded following the
UTF-8 algorithm [16]. [14]. Note that in the UTF-8 algorithm, algorithm characters which
are the same as ASCII (0000 (0x0000 through 007F) 0x007F) are represented as that same
ASCII character in a single byte. The other byte values are used to form
a variable-length encoding of an arbitrary character.

LDAPString ::= OCTET STRING

The LDAPOID is a notational convenience to indicate that the permitted
value of this string is a (UTF-8 encoded) dotted-decimal representation of
an OBJECT IDENTIFIER.

LDAPOID ::= OCTET STRING

For example,

1.3.6.1.4.1.1466.1.2.3

4.1.3. Distinguished Name and Relative Distinguished Name

An LDAPDN and a RelativeLDAPDN are respectively defined to be the
representation of a Distinguished Name and a Relative Distinguished
Name after encoding according to the specification in [4], such that

<distinguished-name> ::= <name>

<relative-distinguished-name> ::= <name-component>

where <name> and <name-component> are as defined in [4].

LDAPDN ::= LDAPString

RelativeLDAPDN ::= LDAPString

Only Attribute Types can be present in a relative distinguished name
component; the options of Attribute Descriptions (next section) must
not
MUST NOT be used in specifying distinguished names.

Wahl, Howes & Howes, Kille [Page 8] Page 8

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996 March 1997

4.1.4. Attribute Type and Description

An AttributeType takes on as its value the textual string associated
with that AttributeType in its specification. This string must begin
with a letter, and only contain ASCII letters and digit characters.
If this string is not known, the

AttributeType will take the ASCII
representation of its ::= LDAPString

Each attribute type has a unique OBJECT IDENTIFIER, IDENTIFIER which has been
assigned to it. This identifier may be written as decimal digits
with components separated by periods, e.g., e.g. "2.5.4.10". The

A specification may also assign one or more textual names for an
attribute type
strings which are used in this version of LDAP are described in [5]. type. These names MUST begin with a letter, and only
contain ASCII letters, digit characters and hyphens. They are case
insensitive.

AttributeType ::= LDAPString

An AttributeDescription (These ASCII characters are identical to ISO 10646
characters whose UTF-8 encoding is a superset of the definition of single byte between 0x00 and 0x7F.)

If the
AttributeType. It server has a textual name for an attribute type, it MUST use
that name for attributes returned in search results. The dotted-decimal
OBJECT IDENTIFIER is only used if there is no textual name for an
attribute type.

Attribute type names are non-unique, as two different specifications
may choose the same ASN.1 definition, but allows additional
options to be specified. They are also case insensitive.

AttributeDescription name.

A server which masters or shadows entries SHOULD list all the attribute
types it supports in the subschema entries, using the attributeTypes
attribute. Servers which support an open-ended set of attributes
SHOULD include at least the attributeTypes value for the 'objectClass'
attribute. Clients MAY retrieve the attributeTypes value from subschema
entries in order to obtain the OBJECT IDENTIFIER and other information
associated with attribute types.

Some attribute type names which are used in this version of LDAP are
described in [5]. Servers may implement additional attribute types.

4.1.5. Attribute Description

An AttributeDescription is a superset of the definition of the
AttributeType. It has the same ASN.1 definition, but allows additional
options to be specified. They are also case insensitive.

AttributeDescription ::= LDAPString

A value of AttributeDescription is based on the following BNF:

<AttributeDescription> ::= <AttributeType> [ ";" <options> ]

<language-option> ::= "lang=" <lang-code>

<lang-code> ::= <printable-ascii>

<binary-option> ::= "binary"

<dynamic-option> ::= "dynamic"

If the "binary" option is present, this overrides any string-based
encoding representation defined for that attribute in [5]. Instead the
attribute is to be transferred as an encoded binary value [11].

If the "lang=" option is present, this associates a natural language
with values for that attribute. The binary and language options may both
be present in an AttributeDescription.
(The language code has no effect on the character set encoding for string
representations of DirectoryString syntax values; UTF-8 is always used).

If the "dynamic" option is present, this implies that the values are not
permanent parts of the directory entry <opt-char> <opt-char>*

<opt-char> ::= ASCII-equivalent letters, numbers and may disappear unexpectedly. hyphen

Wahl, Howes & Howes, Kille [Page 9] Page 9

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996 March 1997

Examples of valid AttributeDescription:

CN
givenName;lang=en-US
CN;lang=ja-JP-kanji
CN;lang=ja-JP-romaji

cn
userCertificate;binary
1.3.6.1.4.1.1466.99.98.97;binary;dynamic

One option, "binary", is defined in this document. Additional documents
may define other options.

An AttributeDescription with one or more options is treated as a subtype
of the attribute without any options. Options present in an
AttributeDescription are never exclusive and may be
listed mutually exclusive. Implementations
should generate the <options> list sorted in ascending order, and servers
MUST treat any order. Not all options are applicable not every attribute,
however.

For example, if a client requests a "description" attribute, two AttributeDescription with the same AttributeType and
options as equivalent. A server
may return will treat an attribute "description;lang=fr". However if the client
requests a "description;lang=en", the server must AttributeDescription with
any options it does not return "description"
or "description;lang=fr", but may return "description;lang=en;dynamic".

Later documents may define additional options. implement as an unrecognized attribute type.

The data type "AttributeDescriptionList" describes a list of 0 or more
attribute types. (A list of zero elements has special significance in
the Search request.)

AttributeDescriptionList ::= SEQUENCE OF
AttributeDescription

4.1.5.

4.1.5.1. Binary Option

If the "binary" option is present in an AttributeDescription, it overrides
any string-based encoding representation defined for that attribute in [5].
Instead the attribute is to be transferred as a binary value encoded using
the Basic Encoding Rules [11]. The syntax of the binary value is an
ASN.1 data type definition which is referenced by the "SYNTAX" part of the
attribute type definition.

The presence or absence of the "binary" option only affects the transfer
of attribute values in protocol; servers store any particular attribute
in a single format. If a client requests that a server return an attribute
in the binary format, but the server cannot generate that format, the
server MUST treat this attribute type as an unrecognized attribute type.
Similarly, clients MUST NOT expect servers to return an attribute in
binary format if the client requested that attribute by name without the
binary option.

This option is intended to be used with attributes whose syntax is a
complex ASN.1 data type, and the structure of values of that type is
needed by clients. Examples of this kind of syntax are "Certificate" and
"CertificateList".

4.1.6. Attribute Value

A field of type AttributeValue takes on as its value either an octet a string
encoding of a AttributeValue data type, or an OCTET STRING containing
an encoded binary value, depending on whether the "binary" option is
present in the companion AttributeDescription to this AttributeValue.

The definition of string encodings for different syntaxes and types may
be found in companions to this document, other documents, and in particular [5].

Wahl, Howes, Kille Page 10

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) March 1997

AttributeValue ::= OCTET STRING

Note that there is no defined limit on the size of this encoding; thus
PDUs including multi-megabyte attributes (e.g. photographs) may be
returned. If the client has limited memory or storage capabilities it

Attributes may wish to set the attrSizeLimit session control before invoking a
search operation.

Clients and server implementors should be aware that attributes whose
type names they do not recognize may defined which have an arbitrary and non-printable syntax.
Implementations must not either MUST NEITHER simply display or nor attempt to decode as
ASN.1 a value if its syntax is not known. The implementation may attempt
to discover the subschema subentry of the source entry, and retrieve the value values of
attributeTypes from it.

Wahl, Howes & Kille [Page 10]

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

4.1.6.

4.1.7. Attribute Value Assertion

The AttributeValueAssertion type definition is similar to the one in
the X.500 directory standards. It contains an attribute description
and a an equality matching rule assertion value suitable for that type.

AttributeValueAssertion ::= SEQUENCE {
attributeDesc AttributeDescription,
assertionValue AssertionValue }

AssertionValue ::= OCTET STRING

If the "binary" option is present in attributeDesc, this signals to the
server that the assertionValue is a binary encoding of the assertion
value.

For all the string-valued user attributes described in [5], the assertion
value syntax is the same as the value syntax. Clients may use
attribute values as assertion values in compare requests and search
filters.

Note however that the assertion syntax may be different than from the value
syntax for operational attributes or for non-equality matching rules.

4.1.7.
These attributes may have an assertion syntax which contains only part
of the value. See section 20.2.1.8 of X.501 [6] for examples.

4.1.8. Attribute

An attribute consists of a type and one or more values of that type.
(Though attributes must MUST have at least one value when stored, due to
access control restrictions the set may be empty when transferred
in protocol. This is described in section 4.5.2, concerning the
PartialAttributeList type.)

Attribute ::= SEQUENCE {
type AttributeDescription,
vals SET OF AttributeValue }

4.1.8.

The order of attribute values within the vals set is undefined and
implementation-dependent, and MUST NOT be relied upon.

Wahl, Howes, Kille Page 11

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) March 1997

4.1.9. Matching Rule Identifier

An X.501(1993) Matching Rule is identified in the LDAP protocol by the
ASCII
printable representation of its OBJECT IDENTIFIER, either as one of the
strings given in [5], or as decimal digits with components separated by
periods, e.g. "caseIgnoreIA5Match" or "1.3.6.1.4.1.453.33.33".

MatchingRuleId ::= LDAPString

4.1.9.

Servers which support matching rules for use in extensibleMatch MUST
list the matching rules they implement in subschema entries. This is
done with the matchingRules and matchingRuleUse attributes.

4.1.10. Result Message

The LDAPResult is the construct used in this protocol to return
success or failure indications from servers to clients. In response
to various requests, requests servers will return responses containing fields
of type LDAPResult to indicate the final status of a protocol
operation request.

Wahl, Howes & Howes, Kille [Page 11] Page 12

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996 March 1997

LDAPResult ::= SEQUENCE {
resultCode ENUMERATED {
success (0),
operationsError (1),
protocolError (2),
timeLimitExceeded (3),
sizeLimitExceeded (4),
compareFalse (5),
compareTrue (6),

authMethodNotSupported (7),
strongAuthRequired (8),
-- 9 reserved --
referral (10), -- new
adminLimitExceeded (11), -- new
unavailableCriticalExtension (12), -- new
-- 13-15 unused --
noSuchAttribute (16),
undefinedAttributeType (17),
inappropriateMatching (18),
constraintViolation (19),
attributeOrValueExists (20),
invalidAttributeSyntax (21),
-- 22-31 unused --
noSuchObject (32),
aliasProblem (33),
invalidDNSyntax (34),
-- 35 reserved for undefined isLeaf --
aliasDereferencingProblem (36),
-- 37-47 unused --
inappropriateAuthentication (48),
invalidCredentials (49),
insufficientAccessRights (50),
busy (51),
unavailable (52),
unwillingToPerform (53),
loopDetect (54),
-- 55-63 unused --
namingViolation (64),
objectClassViolation (65),
notAllowedOnNonLeaf (66),
notAllowedOnRDN (67),
entryAlreadyExists (68),
objectClassModsProhibited (69),
resultsTooLarge (70),
-- cl only 70 reserved for CLDAP --
affectsMultipleDSAs (71), -- new
-- 72-79 unused --
other (80) },
-- 81-90 reserved for APIs --
matchedDN LDAPDN,
errorMessage LDAPString,
referral [3] Referral OPTIONAL }

Wahl, Howes & Howes, Kille [Page 12] Page 13

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996 March 1997

All the result codes with the exception of success, compareFalse and
compareTrue are to be treated as meaning the operation could not be
completed in its entirety.

Most of the result codes are based on problem indications from X.511
error data types. Result codes from 16 to 21 indicate an AttributeProblem,
codes 32, 33, 34 and 36 indicate a NameProblem, codes 48, 49 and 50
indicate a SecurityProblem, codes 51 to 54 indicate a ServiceProblem,
and codes 64 to 69 and 71 indicates an UpdateProblem.

If a client receives a result code which is not listed above, it is to be
treated as an unknown error condition.

The errorMessage field of this construct may, at the servers server's option,
be used to return a string containing a textual, human-readable (terminal
control and page formatting characters should be avoided) error diagnostic.
As this error diagnostic is not standardized, implementations must not MUST NOT rely
on the values returned. If the server chooses not to return a textual
diagnostic, the errorMessage field of the LDAPResult type must MUST contain a
zero length string.

For resultCodes result codes of noSuchObject, aliasProblem, invalidDNSyntax
and aliasDereferencingProblem, the matchedDN field is set to
the name of the lowest entry (object or alias) in the DIT directory that was
matched. If no aliases were dereferenced while attempting to locate
the entry, this will be a truncated form of the name provided. provided, or if
aliases were dereferenced, of the resulting name, as defined in section 12.5
of X.511 [15]. The matchedDN field is to be set to a NULL DN (a zero length
string) string
with all other result codes.

4.1.10.

4.1.11. Referral

The referral field is present in an LDAPResult if the
LDAPResult.resultCode field value is referral, and absent with all other
result codes. It contains a reference to another server (or set of
servers) which may be accessed via LDAP or other protocols.
At least one LDAPURL must Referrals
can be present returned in the Reference.

Referral ::= SEQUENCE responses to any operation request (except unbind and
abandon which do not have responses). At least one LDAPURL MUST be
present in the reference.

Referral ::= SEQUENCE OF LDAPURL

LDAPURL ::= LDAPString -- limited to characters permitted in URLs

The client may MUST contact any one of the listed URLs [14] [7] of servers to
continue the request. Each server in the list must MUST be capable of
processing the operation and presenting a consistent view of the DIT directory
to the client. client, so the client may choose any URL in the list. (The
mechanisms for how servers achieve this are outside the scope of this
document.)

Wahl, Howes, Kille Page 14

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) March 1997

URLs for servers implementing the LDAP protocol are written according
to [9]. If an alias was dereferenced, the dn <dn> part of the URL must MUST
be present, with the new target object name. If this is present,
the client must MUST use this name in its next request to progress this search, the operation,
and if it is not present the client will use the same name as in the
original request. Some servers (e.g. participating in distributed indexing)
may change the provide an different filter in a referral for a search operation. If
the filter part of the URL is present in an LDAPURL, the client must MUST use
this filter in its next request to progress this search, and if it is not
present the client MUST use the same filter as it used for that search.

Note that UTF-8 characters appearing in a DN or search filter may not
be legal for URLs (e.g. spaces) and must MUST be escaped using the % method
in RFC 1738.

Wahl, Howes & Kille [Page 13]

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

Other kinds of URLs may be returned returned, so long as the operation could be
performed using that protocol, and the client has indicated (in a session
control) that it could support that protocol.

If the client has not indicated that it

4.1.12. Controls

A control is capable of handling referrals,
the server must attempt a way to progress the referral on behalf specify extension information. Controls which are
sent as part of the client.
Only if it fails to do so may it return a referral, and the URLs in this
referral must be of the LDAP form.

4.2. Bind Operation

The function of the Bind Operation is to allow authentication information request apply only to be exchanged between the client that request and server.

The Bind Request is defined as follows:

BindRequest are not saved.

Controls ::= [APPLICATION 0] SEQUENCE {
version INTEGER (1 .. 127),
name LDAPDN,
authentication AuthenticationChoice }

AuthenticationChoice ::= CHOICE {
simple [0] OCTET STRING,
-- 1 and 2 reserved
sasl [3] SaslCredentials }

SaslCredentials OF Control

Control ::= SEQUENCE {
mechanism LDAPString,
credentials
controlType LDAPOID,
criticality BOOLEAN DEFAULT FALSE,
controlValue OCTET STRING OPTIONAL }

Parameters

The controlType field MUST be a UTF-8 encoded dotted-decimal representation
of an OBJECT IDENTIFIER which uniquely identifies the Bind Request are:

- version: A version number indicating the version of the protocol to
be used in this protocol session. control. This document describes version
3 of the LDAP protocol. Note that there
prevents conflicts between control names.

The criticality field is no version negotiation,
and either TRUE or FALSE.

If the client should just set this parameter to server recognizes the version control type and it
desires. The client may request version 2, in which case is appropriate for the
operation, the server
must implement only will make use of the protocol as described in [2], and control when performing the
operation.

If the server does not
return any v3-specific result codes or protocol fields.

- name: The name of recognize the directory object that control type and the client wishes to
bind as. This criticality
field may take on a null value (a zero length
string) for is TRUE, the purposes of anonymous binds, when authentication
has been performed at a lower layer, or when using SASL credentials
with a mechanism that includes server MUST NOT perform the LDAPDN in operation, and MUST instead
return the credentials.

- authentication: information used to authenticate resultCode unsupportedCriticalExtension.

If the name, if any,
provided in control is not appropriate for the Bind Request.

Upon receipt of a Bind Request, a protocol server will authenticate operation and criticality field
is TRUE, the requesting client, if necessary. The server will then MUST NOT perform the operation, and MUST instead
return a
Bind Response to the client indicating resultCode unsupportedCriticalExtension.

If the status of control is unrecognized or inappropriate but the authentication.

Wahl, Howes & Kille [Page 14]

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

4.2.1. Sequencing of criticality field
is FALSE, the Bind Request

For some authentication mechanisms, it may be necessary server MUST ignore the control.

The controlValue contains any information associated with the control,
and its format is defined for the client control. The server MUST be prepared
to invoke handle arbitrary contents of the BindRequest multiple times. If at controlValue octet string, including
zero bytes. It is absent only if there is no value information which
is associated with a control of its type.

Wahl, Howes, Kille Page 15

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) March 1997

This document does not define any stage controls. Controls may be defined in
later documents. The definition of a control consists of:

- the client
wishes OBJECT IDENTIFIER assigned to abort the bind process it should drop control,

- whether the underlying
connection. Clients must not invoke operations between two Bind requests
made as part of a multi-stage bind.

Unlike LDAP v2, control is always noncritical, always critical, or
critical at the client need not send a Bind Request in client's option,

- the first
PDU format of the connection. The client may request any operations and controlValue contents of the
server must treat these as unauthenticated (unless authentication has
already occurred at a lower layer). If control.

Servers list the server requires that controls which they recognize in the
client bind first, supportedControl
attribute in the server must reject any request other than
binding or unbinding with root DSE.

4.2. Bind Operation

The function of the "operationsError" result. If Bind Operation is to allow authentication information
to be exchanged between the client did not bind before sending a request and receives an
operationsError, it must close the connection, reopen it and begin
again by first sending a PDU with a server.

The Bind Request. This will aid in
interoperating with servers implementing other versions Request is defined as follows:

BindRequest ::= [APPLICATION 0] SEQUENCE {
version INTEGER (1 .. 127),
name LDAPDN,
authentication AuthenticationChoice }

AuthenticationChoice ::= CHOICE {
simple [0] OCTET STRING,
-- 1 and 2 reserved
sasl [3] SaslCredentials }

SaslCredentials ::= SEQUENCE {
mechanism LDAPString,
credentials OCTET STRING }

Parameters of LDAP.

Clients may send multiple bind requests on an association to change
their credentials. the Bind Request are:

- version: A subsequent bind process has version number indicating the effect version of abandoning
all search and compare operations outstanding.
Authentication or controls from earlier binds are subsequently ignored, and
so if the bind fails, the connection will be treated as anonymous.
Clients must resend their session controls if needed after rebinding,
as session controls may be reset protocol to defaults by servers.

4.2.2 Authentication and Other Security Services

The simple authentication option provides minimal authentication
facilities, with the contents
be used in this protocol session. This document describes version
3 of the authentication field consisting
only of a cleartext password. LDAP protocol. Note that the use of cleartext passwords
is not recommended over open networks when there is no authentication or
encryption being performed by a lower layer; see version negotiation,
and the "Security
Considerations" section.

If no authentication is client just sets this parameter to be performed, or has been performed at a
lower layer, then the simple authentication option should be chosen,
and version it desires.
If the password be of zero length. (This is often done by LDAPv2
clients.)

The sasl choice allows for any mechanism defined for use with SASL [17]
or listed client requests protocol version 2, a server that supports
the version 2 protocol as described in Appendix B to [2] will not return any
v3-specific protocol fields. (Note that not all LDAP servers will
support protocol version 2, since they may be used. The mechanism field contains unable to generate
the attribute syntaxes associated with version 2.)

- name: The name of the mechanism. The credentials field contains the arbitrary data
used for authentication, inside an OCTET STRING wrapper. Note directory object that unlike
some Internet application protocols where SASL is used, LDAP is not
text-based, thus no base64 transformations are performed the client wishes to
bind as. This field may take on a null value (a zero length
string) for the credentials.

If any SASL-based integrity purposes of anonymous binds, when authentication
has been performed at a lower layer, or confidentiality services are enabled, they
take effect following when using SASL credentials
with a mechanism that includes the transmission by LDAPDN in the server and reception by credentials.

- authentication: information used to authenticate the client of name, if any,
provided in the final BindResponse with resultCode success. Bind Request.

Wahl, Howes & Howes, Kille [Page 15] Page 16

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

4.2.3. March 1997

Upon receipt of a Bind Response Request, a protocol server will authenticate
the requesting client, if necessary. The server will then return a
Bind Response is defined as follows.

BindResponse ::= [APPLICATION 1] SEQUENCE {
COMPONENTS OF LDAPResult,
supportedVersion [5] INTEGER (1..127) OPTIONAL,
serverURL [6] LDAPURL OPTIONAL,
serverCreds [7] AuthenticationChoice OPTIONAL }

A BindResponse consists simply of an indication from to the server of client indicating the status of the client's request for authentication.

If the bind was successful,

4.2.1. Sequencing of the resultCode will be success,
otherwise Bind Request

For some authentication mechanisms, it will may be one of:

operationsError
protocolError
authMethodNotSupported
strongAuthRequired
referral
inappropriateAuthentication
invalidCredentials
unavailable
unavailableCriticalExtension

If necessary for the client receives a BindResponse response where the resultCode was
protocolError and the supportedVersion field is absent, it must close
the connection as the server will be unwilling
to accept further
operations. (This is for compatibility with earlier versions of LDAP.)

The serverURL contains invoke the URL of this LDAP server, if it BindRequest multiple times. If at any stage the client
wishes to
provide an "authoritative" URL for itself. Typically this will be a
URL of the "ldap:" type, indicating abort the official host name, bind process it MAY unbind and MUST drop the
name underlying
connection. Clients MUST NOT invoke operations between two Bind requests
made as part of a multi-stage bind.

Unlike LDAP v2, the URL will contain client need not send a Bind Request in the encoded name first
PDU of the server itself. connection. The serverCreds are used client may request any operations and the
server MUST treat these as part of unauthenticated (unless authentication has
already occurred at a SASL-defined bind mechanism; to
allow lower layer). If the server requires that the
client to authenticate bind first, the server to which it is communicating, MUST reject any request other than
binding or to perform "challenge-response" authentication. If the client
bound unbinding with the password choice, or "operationsError" result.

If the SASL mechanism does client did not require
the server to return information to the client, bind before sending a request and receives an
operationsError, it may then send a Bind Request. If this field is also fails
or the client chooses not to be included in the result.

The supportedVersion field contains the minimum of bind on the version supplied
by the client in existing connection, it will
close the BindRequest connection, reopen it and the highest version of LDAP supported begin again by first sending a PDU
with a Bind Request. This will aid in interoperating with servers
implementing other versions of LDAP.

Clients MAY send multiple bind requests on a connection to change
their credentials. A subsequent bind process has the server. If effect of abandoning
all operations outstanding on the client and connection. (This simplifies server both implement
implementation.) Authentication from earlier binds are subsequently
ignored, and so if the protocol
described in this document it will have bind fails, the value 3. This field connection will be absent when responding to treated as
anonymous. If a version 2 SASL transfer encryption or earlier client.

Wahl, Howes & Kille [Page 16]

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

4.3. Unbind Operation

The function of integrity mechanism has been
negotiated, and that mechanism does not support the Unbind Operation is changing of
credentials from one identity to terminate another, then the client MUST instead
establish a protocol
session. The Unbind Operation is defined as follows:

UnbindRequest ::= [APPLICATION 2] NULL new connection.

4.2.2. Authentication and Other Security Services

The Unbind Operation has no response defined. Upon transmission simple authentication option provides minimal authentication
facilities, with the contents of the authentication field consisting
only of an
UnbindRequest, a protocol client may assume cleartext password. Note that the protocol session
is terminated. Upon receipt use of an UnbindRequest, cleartext passwords
is not recommended over open networks when there is no authentication or
encryption being performed by a protocol server
may assume that lower layer; see the requesting client "Security
Considerations" section.

If no authentication is to be performed, or has terminated the session and
that all outstanding requests may be discarded, and may close been performed at a
lower layer, then the
connection. All session controls will simple authentication option MUST be forgotten chosen,
and search result
caches will the password be cleared when a connection closes.

4.4. Session Control Operation

SessionRequest ::= [APPLICATION 17] Controls

SessionResponse ::= [APPLICATION 18] SEQUENCE {
COMPONENTS OF LDAPResult,
unsupportedCtls of zero length. (This is often done by LDAPv2
clients.)

The sasl choice allows for any mechanism defined for use with SASL [12] SEQUENCE OF LDAPString }

Controls ::= SEQUENCE OF SEQUENCE {
controlType LDAPString,
criticality BOOLEAN DEFAULT FALSE,
controlValue
The mechanism field contains the name of the mechanism. The credentials
field contains the arbitrary data used for authentication, inside an
OCTET STRING }

Session Controls wrapper. Note that unlike some Internet application protocols
where SASL is used, LDAP is not text-based, thus no base64 transformations
are requests made performed on the credentials.

Wahl, Howes, Kille Page 17

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) March 1997

If any SASL-based integrity or confidentiality services are enabled, they
take effect following the transmission by the server and reception by
the client which affect its
interaction of the final BindResponse with resultCode success.

If the server. Controls are not saved after a session
unbinds or disconnects abruptly, and do not affect other sessions to
this or other servers. Session controls do not affect operations which
have already connection has been requested on this connection, e.g. if authenticated at a lower layer, the client sends
can override this by sending a search bind request and subsequently sends a sessionControlRequest while the
server is in the middle of sending responses, the session controls which
were in force when the search operation began still apply for all the
results of that search until the SearchResultDone is returned.

Session controls are not cumulative, and
AuthenticationChoice includes a session non-empty password or SASL credentials.

4.2.3. Bind Response

The Bind Response is defined as follows.

BindResponse ::= [APPLICATION 1] SEQUENCE {
COMPONENTS OF LDAPResult,
serverCreds [7] SaslCredentials OPTIONAL }

A BindResponse consists simply of an indication from the server of
the status of the client's request will
override all session controls which were set by a previous request. for authentication.

If a control was set on a previous request and the bind was not mentioned in
a subsequent request, successful, the resultCode will be success,
otherwise it will be reset by the one of:

- operationsError (server encountered an internal error)
- protocolError (unrecognized version number or incorrect PDU structure)
- authMethodNotSupported (unrecognized SASL mechanism name)
- strongAuthRequired (e.g. server does not accept cleartext password)
- referral (this server cannot accept this bind, try another)
- inappropriateAuthentication (server requires the client to its default
value. (This permits session controls, such as supportedProtocol, to
have multiple values.) provide
credentials or use a different authentication mechanism)
- invalidCredentials (e.g. wrong password supplied or bad signature)
- unavailable (e.g. server is shutting down)

If the server is does not capable of setting one or more support the client's requested controls, protocol version,
it should MUST set as many as possible. the resultCode to protocolError.

If any of the controls which client receives a BindResponse response where the
server could not set are marked as critical, resultCode was
protocolError, it must return MUST close the
unavailableCriticalExtension error.

The controlType field must either connection as the server will be a string defined in this section,
or a dotted-decimal representation
unwilling to accept further operations. (This is for compatibility with
earlier versions of an OBJECT IDENTIFIER. This will
aid LDAP, in preventing conflicts between privately-defined control extensions.
String names which the bind was always the first operation,
and there was no negotiation.)

The serverCreds are case insensitive.

Wahl, Howes & used as part of a SASL-defined bind mechanism to
allow the client to authenticate the server to which it is communicating,
or to perform "challenge-response" authentication. If the client
bound with the password choice, or the SASL mechanism does not require
the server to return information to the client, then this field is not
to be included in the result.

4.3. Unbind Operation

The function of the Unbind Operation is to terminate a protocol
session. The Unbind Operation is defined as follows:

UnbindRequest ::= [APPLICATION 2] NULL

Wahl, Howes, Kille [Page 17] Page 18

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996 March 1997

The following controls have been defined:

NAME CRITICAL? VALUE CONTAINS DEFAULT
=================== ================ =============== =============
attrSizeLimit clients option integer Unbind Operation has no limit
dontUseCopy clients option boolean FALSE
usePartialCopy clients option boolean FALSE
referringServer non-critical URL none
chainingProhibited clients option boolean FALSE
supportedProtocol non-critical response defined. Upon transmission of an
UnbindRequest, a protocol name none
useAliasOnUpdate clients option boolean FALSE
manageDsaIT critical boolean FALSE
preferredLanguage non-critical string no preference

The attrSizeLimit control client may be critical or non-critical at assume that the client's
request. The value field contains either an empty string, implying no
limit, or a string representation protocol session
is terminated. Upon receipt of an UnbindRequest, a positive integer, e.g. "10000".
The default if this control is not present is protocol server
may assume that there is no limit.
The attrSizeLimit number the requesting client has terminated the session and
that all outstanding requests may be discarded, and may close the
connection.

4.4. Unsolicited Notification

An unsolicited notification is a size in bytes of an LDAPMessage sent from the largest encoded value
which server to the
client which is capable of processing. Servers should not return
attribute values in a search response which are larger than this size.
(If attribute values are excluded because of this control, to any LDAPMessage received by the
incompleteEntry attribute must be present with the value TRUE server.
It is used to signal an extraordinary condition in the
SearchResultEntry).

The dontUseCopy control may be critical server or non-critical at in the client's
request. The value field contains either "TRUE" or "FALSE".
The default if this control is not set is "FALSE". This control only
affects
connection between the Search client and Compare operations. If present the server. The notification is of an
advisory nature, and set to "TRUE",
servers should the server will not make use of information from cached or shadowed
copies of entries in these operations. This control overrides expect any
setting of the usePartialCopy control.

The usePartialCopy control may response to be critical or non-critical at
returned from the client's
request. The value field contains either "TRUE" or "FALSE". client.

The default if this control is not set unsolicited notification is "FALSE". This control only
affects structured as an LDAPMessage in which the Search
messageID is 0 and Compare operations. If protocolOp is of the dontUsecopy control extendedResp form. The
responseName field of the ExtendedResponse is
set to "TRUE", present. The LDAPOID
value MUST be unique for this control is ignored. If usePartialCopy is present notification, and
set to "TRUE", then if a contacted server holds at least one attribute not be used in a
shadow or cached copy any other
situation.

One unsolicited notification is defined in this document.

4.4.1. Notice of an entry, then that entry Disconnection

This notification may be used to satisfy by the request, even if not all server to advise the requested attributes are in client that
the shadowed
copy. If this control is "FALSE" and dontUseCopy server is also "FALSE", about to close the
server must not return attributes from connection due to an incomplete shadow copy of error condition.
Note that this notification is NOT a response to an
entry unless none of the unbind requested attributes or their subtypes were
excluded from by
the shadow copy. (How servers replicate information and
configure shadowing is outside client: the scope server MUST follow the procedures of this specification.)

The referringServer control section 4.3. This
notification is always non-critical. The value field
contains the URL of another server which referred intended to assist clients in distinguishing between an operation
error condition and a transient network failure. As with a connection
close due to this
server. This control must only be present if network failure, the connection client MUST NOT assume that any
outstanding requests which modified the directory have succeeded or failed.

The responseName is being
made only to process a referral. If 1.3.6.1.4.1.1466.20036, the connection will be held open to
handle referrals from multiple servers this control must be omitted.
There response field is no protocol effect of this control; it absent,
and the resultCode is used to assist in
tracing knowledge inconsistencies in indicate the distributed directory.

Wahl, Howes & Kille [Page 18]

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

The chainingProhibited control may be critical or non-critical at reason for the
client's request. disconnection.

The value must following resultCode values are to be either "TRUE" or "FALSE". To aid
interoperability with LDAPv2 clients, the default if this control is not
set is "FALSE". If used in this control is present and set to "TRUE", the notification:

- protocolError: The server must has received data from the client in which
the LDAPMessage structure could not contact any other servers as part of processing operations
requested by this client, if it would be possible to instead
return to parsed.

- strongAuthRequired: The server has detected that an established
underlying security association protecting communication between the
client a referral. If the and server is a gateway to X.500, has unexpectedly failed or been compromised.

- unavailable: This server will stop accepting new connections and DAP is not a supported
operations on all existing connections, and be unavailable for an
extended period of time. The client referral protocol (see next paragraph), may make use of an alternative
server.

After sending this notice, the server must set MUST close the chainingProhibited service control on any DAP
or DSP requests it makes.

The supportedProtocol control is always non-critical. The field is
a string name of a protocol which connection. After
receiving this notice, the client implements. The name of MUST NOT transmit any further on the protocol
connection, and may be "ldap", "cldap", "dap", any IANA-assigned protocol
name or URL mechanism, or "*" abruptly close the connection.

Wahl, Howes, Kille Page 19

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) March 1997

4.5. Search Operation

The Search Operation allows a client to indicate request that any type of referral may
be returned. If this control is present, a server must return search be
performed on its behalf by a
referral, rather than itself chain to another server using one of the
indicated protocol. server. This control may can be present multiple times in a
session control if the client wishes used to name multiple protocols it
supports.

If the supportedProtocol control is absent and the server is capable of
contacting other servers, then it must not return results with
referrals, as described in 4.1.10, or SearchResultContinuation, as
described in 4.5.3, unless the server is not capable of contacting
other servers, in which case it may return read attributes
from a referral single entry, from entries immediately below a particular entry,
or continuation
containing a URL whole subtree of type "LDAP".

It entries.

4.5.1. Search Request

The Search Request is recommended that clients, defined as a minimum, support LDAP referrals, follows:

SearchRequest ::= [APPLICATION 3] SEQUENCE {
baseObject LDAPDN,
scope ENUMERATED {
baseObject (0),
singleLevel (1),
wholeSubtree (2) },
derefAliases ENUMERATED {
neverDerefAliases (0),
derefInSearching (1),
derefFindingBaseObj (2),
derefAlways (3) },
sizeLimit INTEGER (0 .. maxInt),
timeLimit INTEGER (0 .. maxInt),
typesOnly BOOLEAN,
filter Filter,
attributes AttributeDescriptionList }

Filter ::= CHOICE {
and set the supportedProtocol control to be "ldap".

The useAliasOnUpdate control may be critical [0] SET OF Filter,
or non-critical at the
client's request. The value must be either "TRUE" or "FALSE". To
aid interoperability with LDAPv2 clients, the default if this control
is [1] SET OF Filter,
not set is "FALSE". If [2] Filter,
equalityMatch [3] AttributeValueAssertion,
substrings [4] SubstringFilter,
greaterOrEqual [5] AttributeValueAssertion,
lessOrEqual [6] AttributeValueAssertion,
present and set to TRUE, the server [7] AttributeDescription,
approxMatch [8] AttributeValueAssertion,
extensibleMatch [9] MatchingRuleAssertion }

SubstringFilter ::= SEQUENCE {
type AttributeDescription,
-- at least one must
permit alias names to be used as components present
substrings SEQUENCE OF CHOICE {
initial [0] LDAPString,
any [1] LDAPString,
final [2] LDAPString } }

MatchingRuleAssertion ::= SEQUENCE {
matchingRule [1] MatchingRuleId OPTIONAL,
type [2] AttributeDescription OPTIONAL,
matchValue [3] AssertionValue,
dnAttributes [4] BOOLEAN DEFAULT FALSE }

Parameters of a Distinguished Name in
Add, Modify and Delete operations. If the server Search Request are:

Wahl, Howes, Kille Page 20

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) March 1997

- baseObject: An LDAPDN that is a gateway the base object entry relative to X.500,
it must set
which the useAliasOnUpdate critical extension on any DAP/DSP
AddEntry, ModifyEntry and RemoveEntry requests it makes if this
control search is "TRUE". This control does not affect the ModifyDN operation,
which only allows Distinguished Names to be provided.

The manageDsaIT control is always critical. The value must performed.

- scope: An indicator of the scope of the search to be either
"TRUE" or "FALSE". performed. The default, if
semantics of the possible values of this control is not set, is "FALSE".
This control affects field are identical to the name resolution behavior
semantics of the server scope field in the X.511 Search Operation.

- derefAliases: An indicator as to
permit a manager how alias objects are to read and modify knowledge references and other
X.500 server-specific attributes. If be
handled in searching. The semantics of the server is a gateway to
X.500, it must set possible values of
this field are:

neverDerefAliases: do not dereference aliases in searching
or in locating the manageDsaIT critical extension, as well as base object of the
appropriate common arguments, on any DAP/DSP requests it makes, based on
this control.

Wahl, Howes & Kille [Page 19]

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

The preferredLanguage control is always non-critical. The use search;

derefInSearching: dereference aliases in subordinates of this
control
the base object in searching, but not in locating the
base object of the search;

derefFindingBaseObj: dereference aliases in locating
the base object of the search, but not when searching
subordinates of the base object;

derefAlways: dereference aliases both in searching and its impact on in
locating the directory will base object of the search.

- sizelimit: A sizelimit that restricts the maximum number of entries
to be defined returned as a result of the search. A value of 0 in future drafts.
The default if this control is not set, is
field indicates that there is no preferred
language.

4.5. Search Operation

The Search Operation allows a client to request sizelimit restrictions are in effect for
the search.

- timelimit: A timelimit that restricts the maximum time (in seconds)
allowed for a search. A value of 0 in this field indicates that no
timelimit restrictions are in effect for the search.

- typesOnly: An indicator as to whether search results will contain
both attribute types and values, or just attribute types. Setting
this field to TRUE causes only attribute types (no values) to be
performed on its behalf by a server. This can be used
returned. Setting this field to read attributes
from a single entry, or FALSE causes both attribute types
and values to be returned.

- filter: A filter that defines the conditions that must be fulfilled
in order for the search to match a whole subtree given entry. The 'and', 'or' and
'not' choices may be used to form boolean combinations of entries.

4.5.1. Search Request filters. At
least one filter element MUST be present in an 'and' or 'or'
choice. The Search Request is defined as follows:

SearchRequest ::= [APPLICATION 3] SEQUENCE {
baseObject LDAPDN, others match against individual attribute values of
entries in the scope ENUMERATED {
baseObject (0),
singleLevel (1),
wholeSubtree (2) },
derefAliases ENUMERATED {
neverDerefAliases (0),
derefInSearching (1),
derefFindingBaseObj (2),
derefAlways (3) },
sizeLimit INTEGER (0 .. maxInt),
timeLimit INTEGER (0 .. maxInt),
typesOnly BOOLEAN, of the search.

(Implementor's note: the 'not' filter Filter,
attributes AttributeDescriptionList,
pageSizeLimit [0] INTEGER OPTIONAL,
sortKeys [1] SortKeyList OPTIONAL,
prevSearchId [2] MessageID OPTIONAL,
startLocation [3] INTEGER OPTIONAL }

SortKeyList ::= SEQUENCE OF SEQUENCE {
attributeType AttributeType,
orderingRule [0] MatchingRuleId OPTIONAL,
reverseOrder [1] BOOLEAN DEFAULT FALSE }

Filter ::= CHOICE {
and [0] SET OF Filter,
or [1] SET OF Filter,
not [2] Filter,
equalityMatch [3] AttributeValueAssertion,
substrings [4] SubstringFilter,
greaterOrEqual [5] AttributeValueAssertion,
lessOrEqual [6] AttributeValueAssertion,
present [7] AttributeType,
approxMatch [8] AttributeValueAssertion,
extensibleMatch [9] MatchingRuleAssertion } is an example of a tagged
choice in an implicitly-tagged module. In BER this is treated as
if the tag was explicit.)

Wahl, Howes & Howes, Kille [Page 20] Page 21

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

SubstringFilter ::= SEQUENCE { March 1997

The extensibleMatch is new in this version of LDAP. If the
matchingRule field is absent, the type AttributeDescription,
-- at least one must field MUST be present
substrings SEQUENCE OF CHOICE {
initial [0] LDAPString,
any [1] LDAPString,
final [2] LDAPString } }

MatchingRuleAssertion ::= SEQUENCE {
matchingRule [1] MatchingRuleId OPTIONAL,
type [2] AttributeType OPTIONAL,
matchValue [3] AssertionValue,
dnAttributes [4] BOOLEAN DEFAULT FALSE }

Parameters of present, and
the Search Request are:

- baseObject: An LDAPDN equality match is performed for that type. If the type field is
absent and matchingRule is present, the base object matchValue is compared
against all attributes in an entry relative to which support that matchingRule,
and the search is to be performed.

- scope: An indicator of matchingRule determines the scope of syntax for the search to assertion value.
If the type field is present and matchingRule is present, the
matchingRule MUST be performed. The
semantics of one permitted for use with that type.
If the possible values of this dnAttributes field are identical is set to TRUE, the
semantics of match is applied
against all the scope field attributes in the X.511 Search Operation.

- derefAliases: An indicator an entry's distinguished name as to how alias objects are to be be
handled in searching.
well. (Editors note: The semantics of the possible values of
this dnAttributes field are:

neverDerefAliases: do is present so that there
does not dereference aliases in searching
or in locating the base object need to be multiple versions of the search;

derefInSearching: dereference aliases in subordinates generic matching rules such as
wordMatch, one to apply to entries and another to apply to entries and
dn attributes as well).

Servers MUST ignore parts of filters which use unrecognized attribute
types (that part of the base object in searching, but filter does not in locating match any entry). If the
base object of entire
filter is ignored, no entries match. A server may return the search;

derefFindingBaseObject: dereference aliases in locating
the base object of the search, but error
inappropriateMatching if it does not when searching
subordinates of the base object;

derefAlways: dereference aliases both in searching and in
locating the base object permit a particular form of matching
(e.g. substrings match on an integer value). Servers may return the search.

- sizelimit: A sizelimit that restricts
error invalidAttributeSyntax if the maximum number value part of entries
to be returned as a result of the search. A value search filter is
improperly specified. More details of 0 in this
field indicates that no sizelimit restrictions filter processing are given in effect for
the search.
section 7.8 of X.511 [15].

- timelimit: attributes: A timelimit that restricts list of the maximum time (in seconds)
allowed for attributes from each entry found as a search. A value
result of 0 in this field indicates that no
timelimit restrictions are in effect for the search.

- typesOnly: An indicator as to whether search results will contain
both attribute types and values, or just attribute types. Setting
this field to TRUE causes only attribute types (no values) to be
returned. Setting this field to FALSE causes both attribute types
and values to be returned.

Wahl, Howes & Kille [Page 21]

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

- filter: A filter that defines the conditions An empty list signifies that must be fulfilled
all user attributes from each entry found in order for the search are to match a given entry. The 'and', 'or' and
'not' choices may be used to form boolean combinations of filters. At
least one filter element must be present in an 'and' or 'or'
choice. The others match against individual attribute values of
entries in the scope of the search.

The extensibleMatch is new in this version of LDAP. If the
matchingRule field is absent, the type field must be present, and
the equality match is performed for that type. If the type field is
absent and matchingRule is present, the matchValue is compared
against all attributes in an entry which support that matchingRule,
and the matchingRule determines the syntax for the assertion value.
If the type field is present and matchingRule is present, the
matchingRule must be one permitted for use with that type.
If the dnAttributes field is set to TRUE, the match is applied
against all the attributes in an entry's distinguished name as
well. (Editors note: The dnAttributes field is present so that there
does not need to be multiple versions of generic matching rules such as
wordMatch, one to apply to entries and another to apply to entries and
dn attributes as well).

- attributes: A list of the attributes from each entry found as a
result of the search to be returned. An empty list signifies that
all user attributes from each entry found in the search are to be
returned, as does
returned, as does the special attribute description string "*". (the
latter technique allows the client to request all user attributes
along with selected operational attributes). If the client does not
want any attributes returned, it can request only the attribute with
OID "1.1". "1.1" (this OID is arbitrary). Attributes must MUST be named at most
once in the list, and are returned at most once in an entry.

Servers MUST ignore requests for unrecognized attribute types. If
no attributes specified by the client are recognized, then no attributes
will be included in the result entries.

Client implementors should note that even if all user attributes are
requested, some attributes of the entry may not be included in search
results due to access control or other restrictions. Furthermore,
servers will not return operational attributes, such as modifyRights objectClasses or
attributeTypes, unless they are listed by name, since there may be
extremely large number of values for certain operational attributes.
(A list of operational attributes for use in LDAP is given in [5].)

- pageSizeLimit: if present, then if more entries are to

Note that an X.500 "list"-like operation can be returned than
the pageSizeLimit, emulated by the server must return only as many as this limit
before returning client
requesting a one-level LDAP search operation with a filter checking for
the SearchResultDone response. If existence of the same or fewer
entries than this limit are to objectClass attribute, and that an X.500 "read"-like
operation can be returned, emulated by a base object LDAP search operation with
the same filter. A server must return all
the entries and the SearchResultDone response.

The pageSizeLimit does not affect SearchResultReference responses, which
are provides a gateway to X.500 is not counted as entries and of which any number may be returned by the
server.

If operating over connectionless data transport,
required to use the client must not
set this field. Read or List operations, although it may choose to
do so.

Wahl, Howes & Howes, Kille [Page 22] Page 22

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

If a pageSizeLimit was set and reached during March 1997

4.5.2. Search Result

The results of the search, search attempted by the client
will be able to request more server upon receipt of the entries using a subsequent
SearchRequest with the prevSearchId field present.

It is strongly recommended that clients include the sortKeys field when
including this field.

- sortKeys: If this field is present, then it specifies one or more
attribute types and matching rules, and the
Search Request are returned entries must
be sorted in order based on these Search Responses, which are LDAP
messages containing either SearchResultEntry, SearchResultReference,
ExtendedResponse or SearchResultDone data types. If

SearchResultEntry ::= [APPLICATION 4] SEQUENCE {
objectName LDAPDN,
attributes PartialAttributeList }

PartialAttributeList ::= SEQUENCE OF SEQUENCE {
type AttributeDescription,
vals SET OF AttributeValue }
-- implementors should note that the reverseOrder field is
set to TRUE, then PartialAttributeList may have
-- zero elements (if none of the entries will be presented in reverse sorted
order.

Only if the server does not recognize any attributes of that entry were
-- requested, or could be returned), and that the attribute types, the
ordering rule associated with an attribute type is not applicable, vals set may also
-- have zero elements (if types only was requested, or
none of all values were
-- excluded from the attributes in result.)

SearchResultReference ::= [APPLICATION 19] SEQUENCE OF LDAPURL
-- at least one LDAPURL element must be present

SearchResultDone ::= [APPLICATION 5] LDAPResult

Upon receipt of a Search Request, a server will perform the necessary
search responses are of these types,
then the sortKeys field is not used and result entries are returned
in random order. DIT.

If the server does not support sorting with the requested attributes
or matching rules, then it must return only protocolError (which LDAP session is what
an LDAPv2 operating over a connection-oriented transport
such as TCP, the server would return), undefinedAttributeType or
inappropriateMatching and no searchResultEntry will return to the client a sequence of
responses in separate LDAP messages. There may be zero or
searchResultReference responses.

If more
responses containing SearchResultEntry, one for each entry found
during the sortKeys field is absent, there is no defined order search. There may also be zero or more responses
containing SearchResultReference, one for returning
entries in a search result.

- prevSearchId: If this field is present, each area not explored by
this informs the server that,
with possibly the exception of during the value of search. The SearchResultEntry and
SearchResultReference PDUs may come in any order. Following all the startLocation field,
this request is identical
SearchResultReference responses and all SearchResultEntry responses
to a searchRequest made previously on this
association. If be returned by the server, the server does not recognize this as will return a response containing
the message id SearchResultDone, which contains an indication of a previous search operation, it must silently ignore this field and
perform this search as normal. The client must ensure success, or
detailing any errors that have occurred.

Each entry returned in a SearchResultEntry will contain all fields,
other than startLocation, are the same attributes,
complete with associated values if necessary, as specified in the earlier search,
otherwise the contents
attributes field of the entries Search Request. Return of attributes is subject
to access control and other administrative policy. Some attributes may
be returned from this search are not
defined. If clients are performing in binary format (indicated by the same search more than twice on an
association, then AttributeDescription in the prevSearchId field of all but
response having the first search
must contain binary option present).

Some attributes may be constructed by the messageID server and appear in a
SearchResultEntry attribute list, although they are not stored attributes
of an entry. Clients MUST NOT assume that first search.

- startLocation: this field may all attributes can be present modified,
even if permitted by access control.

Response LDAPMessages of the pageSizeLimit is
present. After filtering and selecting ExtendedResponse form are reserved for
returning information associated with a control requested by the entries to client.
These may be returned defined in
a search, future versions of this document.

Wahl, Howes, Kille Page 23

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) March 1997

4.5.3. Continuation References in the Search Result

If the server will discard this many entries before starting was able to return SearchResultEntry responses. Thus setting startLocation 0 is locate the same as not including a startLocation field. If entry referred to by the client sends a
value of startLocation which is larger than
baseObject but was unable to search all the number of entries in the
result, scope at
and under the server will only baseObject, the server may return any one or more
SearchResultReference, each containing a reference to another set of
servers for continuing the operation. The server will return
a SearchResultReference
responses, for each new base object with a
particular scope and then the SearchResultDone response. (The filter. A server should
indicate in the SearchResultDone a value of totalCount which MUST NOT return any
SearchResultReference if it has not located the client
may use to make a better choice of startLocation baseObject and
thus has not searched any entries; in this case it would return a subsequent search).
SearchResultDone containing a referral resultCode.

The startLocation does not affect SearchResultReference responses, which
are not counted as entries.

Wahl, Howes & Kille [Page 23]

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

It is strongly recommended that clients include the sortKeys field when
including this field.

If the client includes the attribute type name 'modifyRights' in of the
search request attribute same data type list when performing a baseObject search,
then as the server may return Referral.
URLs for servers implementing the modifyRights attribute as LDAP protocol are written according
to [9]. The <dn> part of MUST be present in the response attributes for that entry. URL, with the new target
object name. The value of client MUST use this attribute
is described name in section 6.2.2.1 its next request.
Some servers (e.g. part of [5], and corresponds to a distributed index exchange system) may provide
a different filter in the X.511(93)
ModifyRights field URLs of the ReadResponse.

Note that an X.500 "list"-like operation can be emulated by SearchResultReference. If the client
requesting a one-level LDAP search operation with a
filter checking for
the existence part of the objectClass attribute, and that URL is present in an X.500 "read"-like
operation can be emulated by a base object LDAP search operation with URL, the same filter. A server which provides a gateway client MUST use the
new filter in its next request to X.500 progress the search, and if the filter
part is not
required to absent the client will use again the Read or List operations, although it filter from the original
search.

Other kinds of URLs may choose be returned so long as the operation could be
performed using that protocol.

The name of an unexplored subtree in a SearchResultReference need not be
subordinate to
do so.

If the base object.

In order to complete the search, the client MUST issue a new search filter includes an equality match of
operation for each SearchResultReference that is returned. Note that the objectClass
attribute
abandon operation described in section 4.11 applies only to a particular
operation sent on a connection between a client and server, and the value "subentry", then if the
client has multiple outstanding search operations to different servers,
it MUST abandon each operation individually.

4.5.3.1. Example

For example, suppose the contacted server (hosta) holds the entry
"O=MNN,C=WW" and the entry "CN=Manager,O=MNN,C=WW". It knows that either
LDAP-capable servers (hostb) or (hostc) hold "OU=People,O=MNN,C=WW" (one
is converting
to an X.500 protocol, the subentries service control must be set.
Thus clients must not search for both subentries master and ordinary entries
with the other server a single shadow), and that LDAP-capable
server (hostd) holds the subtree "OU=Roles,O=MNN,C=WW". If a subtree
search operation.

4.5.2. Search Result

The results of "O=MNN,C=WW" is requested to the search attempted by contacted server, the
server upon receipt of a
Search Request are returned in Search Responses, which are LDAP
messages containing either SearchResultEntry, SearchResultReference,
SearchResultDone or SearchResultFull data types. may return the following responses:

SearchResultEntry ::= [APPLICATION 4] SEQUENCE {
objectName LDAPDN,
attributes PartialAttributeList }

PartialAttributeList ::= SEQUENCE OF SEQUENCE for O=MNN,C=WW
SearchResultEntry for CN=Manager,O=MNN,C=WW
SearchResultReference {
type AttributeDescription,
vals SET OF AttributeValue
ldap://hostb/OU=People,O=MNN,C=WW
ldap://hostc/OU=People,O=MNN,C=WW
}
-- implementors should note that the PartialAttributeList may have
-- zero elements (if none of the attributes of that entry were
-- requested, or could be returned), and that the vals set may also
-- have zero elements (if types only was requested, or all the values
-- exceeded the attribute size limit or were excluded because of
-- access control).
SearchResultReference ::= [APPLICATION 19] SEQUENCE OF LDAPURL
-- at least one LDAPURL element must be present

SearchResultDone ::= [APPLICATION 5] SEQUENCE {
COMPONENTS OF LDAPResult,
totalCount [8] INTEGER OPTIONAL
ldap://hostd/OU=Roles,O=MNN,C=WW
}
SearchResultDone (success)
Wahl, Howes & Howes, Kille [Page 24] Page 24

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

SearchResultFull ::= SEQUENCE OF CHOICE {
entry SearchResultEntry,
reference SearchResultReference,
resultCode SearchResultDone }

Upon receipt of a Search Request, March 1997

Client implementors should note that when following a
SearchResultReference, additional SearchResultReference may be
generated. Continuing the example, if the client contacted the
server will perform (hostb) and issued the necessary search of for the DIT.

If subtree
"OU=People,O=MNN,C=WW", the LDAP session is operating over a connection-oriented transport
such server might respond as TCP, follows:

SearchResultEntry for OU=People,O=MNN,C=WW
SearchResultReference {
ldap://hoste/OU=Managers,OU=People,O=MNN,C=WW
}
SearchResultReference {
ldap://hostf/OU=Consultants,OU=People,O=MNN,C=WW
}
SearchResultDone (success)

If the contacted server does not hold the base object for the search,
then it will return a referral to the client. For example, if the
client requests a sequence subtree search of
responses in separate LDAP messages. There may be zero or more
responses containing SearchResultEntry, one for each entry found
during "O=XYZ,C=US" to hosta, the search. There server
may also be zero or more responses return only a SearchResultDone containing SearchResultReference, one for each area not explored by
this server during the search. The SearchResultEntry and
SearchResultReferences may come in any order. Following all the
SearchResultReference responses and all SearchResultEntry responses up
to a pageSizeLimit (if any), the server will return a response containing
the SearchResultDone, which contains an indication of success, or
detailing any errors that have occurred.

If the LDAP session is operating over referral.

SearchResultDone (referral) {
ldap://hostg/O=XYZ,C=US
}

4.6. Modify Operation

The Modify Operation allows a connectionless transport such
as UDP, the server will return to the client only one response to the
search, an LDAPMessage containing request that a SearchResultFull data type. All (if
any) but the last element modification
of the an entry be performed on its behalf by a server. The Modify
Request is defined as follows:

ModifyRequest ::= [APPLICATION 6] SEQUENCE {
object LDAPDN,
modification SEQUENCE OF must be SEQUENCE {
operation ENUMERATED {
add (0),
delete (1),
replace (2) },
modification AttributeTypeAndValues } }

AttributeTypeAndValues ::= SEQUENCE {
type AttributeDescription,
vals SET OF AttributeValue }

Parameters of the
SearchResultEntry or SearchResultReference types, and the last must Modify Request are:

- object: The object to be modified. The value of this field contains the
DN of the SearchResultDone type.

The SearchResultFull is never returned over a connection-oriented
transport.

Each entry returned in a SearchResultEntry to be modified. The server will contain all attributes,
complete with associated values if necessary, as specified not perform any alias
dereferencing in determining the
attributes field of the Search Request. Return object to be modified.

Wahl, Howes, Kille Page 25

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) March 1997

- modification: A list of attributes is subject modifications to access control and other administrative policy. Some attributes may be returned in binary format (indicated by performed on the AttributeDescription entry.
The entire list of entry modifications MUST be performed
in the
response having the binary option present), or in order they are listed, as a language-specific
subtype (indicated by the AttributeDescription in single atomic operation. While
individual modifications may violate the response having directory schema, the
language option present).

The following are not strictly attributes of an
resulting entry (or a subentry),
but may appear in after the result entire list if requested.

- entryName. This operational attribute is maintained by the server and
appears to be present in each entry. The value of this attribute modifications is performed
MUST conform to the distinguished name requirements of the entry from which it is read. It
is expected directory schema. The
values that may be taken on by the client would request and the server would return
this attribute 'operation' field in binary.

- modifyRights. Each value is each
modification construct have the encoding of an element of modifyRights.
The attribute is specific following semantics respectively:

add: add values listed to the particular search operation and given attribute, creating
the requestor, and must not be cached or replicated.

Wahl, Howes & Kille [Page 25]

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

- incompleteEntry. This attribute's value is TRUE attribute if one or more
attributes are not present in necessary;

delete: delete values listed from the PartialAttributeList, because their
size would have exceeded given attribute,
removing the entire attribute size limit, if no values are listed, or
if a partial
shadow copy all current values of the entry was used to satisfy the request and some
requested attributes attribute are not returned. It is never set just because
typesOnly was set to TRUE, or because a requested listed for
deletion;

replace: replace all existing values of the given attribute was not
actually present in
with the entry.

- fromEntry. The server may return this attribute's value as FALSE new values listed, creating the attribute if it
is known that
did not already exist. A replace with no value will delete
the search is based upon a shadow or cached copy entire attribute.

The result of the
entry, and may return it as TRUE if modify attempted by the server masters the entry.

In upon receipt of a SearchResultEntry,
Modify Request is returned in a Modify Response, defined as an encoding optimization, the value follows:

ModifyResponse ::= [APPLICATION 7] LDAPResult

Upon receipt of the
objectName LDAPDN may have a trailing '*' character Modify Request, a server will perform the necessary
modifications to refer the DIT.

The server will return to the
baseObject client a single Modify Response
indicating either the successful completion of the corresponding searchRequest. For example, if DIT modification,
or the
baseObject is specified as "o=UofM, c=US", then reason that the following objectName
LDAPDNs modification failed. Note that due to the
requirement for atomicity in a response would have applying the indicated meanings

objectName returned actual LDAPDN denoted
____________________________________________________
"*" "o=UofM, c=US"
"cn=Babs Jensen, *" "cn=Babs Jensen, o=UofM, c=US"

If list of modifications in
the pageSizeLimit field was present, Modify Request, the server client may indicate the total
number expect that no modifications of entries which could
the DIT have matched been performed if the search filter in Modify Response received indicates
any sort of error, and that all requested modifications have been
performed if the field
totalCount Modify Response indicates successful completion of
the SearchResultDone. The total count would be Modify Operation. If the same or
greater than connection fails, whether the number of SearchResultEntry responses returned at this
time. If it modification
occurred or not is greater, then indeterminate.

Note that due to the server did simplifications made in LDAP, there is not return all a direct
mapping of the responses
because modifications in an LDAP ModifyRequest onto the pageSizeLimit was reached. This field is not affected by any
requested startLocation field. Client implementors should note that
subsequent search requests with the same fields may return
EntryModifications of a DAP ModifyEntry operation, and different value
for totalCount if
implementations of LDAP-DAP gateways may use different means of
representing the DIT is being modified by other users. The totalCount
field must be absent if change. If successful, the pageSizeLimit field was not included in final effect of the
request.

Servers should not return
operations on the resultCode sizeLimitExceeded merely because entry MUST be identical.

Wahl, Howes, Kille Page 26

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) March 1997

4.7. Add Operation

The Add Operation allows a pageSizeLimit was reached.

4.5.3. Continuation References in the Search Result

If the server was able client to locate request the addition of an entry referred to by the
baseObject but was unable to search all
into the entries in directory. The Add Request is defined as follows:

AddRequest ::= [APPLICATION 8] SEQUENCE {
entry LDAPDN,
attributes AttributeList }

AttributeList ::= SEQUENCE OF SEQUENCE {
type AttributeDescription,
vals SET OF AttributeValue }

Parameters of the scope at
and under Add Request are:

- entry: the baseObject, Distinguished Name of the server may return one or more
SearchResultReference, each containing a reference entry to another set be added. Note that
all components of
servers the name except for continuing the operation. The server must return at most
one SearchResultReference last RDN component MUST
exist for a new subordinate base object with a
particular scope and filter. A server must not return a
SearchResultReference if it has not located the baseObject and
thus has add to succeed. Note also that the server will not searched
dereference any entries; aliases in this case it would return a
SearchResultDone containing a referral resultCode.

Wahl, Howes & Kille [Page 26]

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

The SearchResultReference is of the same data type as locating the Referral.
A URL in a SearchResultReference entry to be added, and that
servers may enforce restrictions on where entries may only be included if the client has
indicated (in located.

- attributes: the session controls) that it is able to handle list of attributes that
protocol. If make up the client has not indicated any protocols which content of the
server could use to return
entry being added. Clients MUST include distinguished values (those
forming the entry's own RDN) in a SearchResultReference, this list, the server must
itself process objectClass attribute,
and values of any mandatory attributes of the entire search. If listed object classes.

The result of the server could not contact
all other servers, it may return one or more SearchResultReference for
unexplored subtrees, and must indicate also that only partial results were
returned add attempted by setting the resultCode server upon receipt of a Add
Request is returned in the SearchResultDone to be something
other than success, such Add Response, defined as timeLimitExceeded.

URLs for servers implementing the LDAP protocol are written according follows:

AddResponse ::= [APPLICATION 9] LDAPResult

Upon receipt of an Add Request, a server will attempt to [9]. perform the
add requested. The dn part must be present in result of the URL, with add attempt will be returned to the new target
object name. The
client must use this name in its next request.
Some servers (e.g. participating in distributed indexing) may change the filter. If Add Response.

4.8. Delete Operation

The Delete Operation allows a client to request the filter part removal of the URL is present in an LDAP URL,
the client must use this filter in its next request to progress this
search, and if
entry from the filter directory. The Delete Request is absent the client will use the same filter defined as
it used for that search.

Other kinds follows:

DelRequest ::= [APPLICATION 10] LDAPDN

The Delete Request consists of URLs may be returned so long as the operation could be
performed using that protocol, and Distinguished Name of the client has indicated (in a
session control) that it is able
entry to handle be deleted. Note that protocol.

The the server will not dereference aliases
while resolving the name of an unexplored subtree in a SearchResultReference need not the target entry to be removed, and that only
leaf entries (those with no subordinate to the base object if an alias was dereferenced, however it
must not entries) may be a prefix deleted with this
operation.

The result of the base object, otherwise the client will
loop. (Client implementations must detect loops; see section 6.2.)

Note: delete attempted by the "X.500 Non-Specific Subordinate Reference" server upon receipt of a
Delete Request is not permitted returned in
LDAP. Servers must not return multiple SearchResultReference for the same
subtree, and any one Delete Response, defined as follows:

DelResponse ::= [APPLICATION 11] LDAPResult

Upon receipt of (not all of) the servers listed in a
SearchResultReference may be contacted to perform the entire search in Delete Request, a
particular subtree.

4.5.3.1. Example

For example, suppose the contacted server (hosta) holds the entry
"O=MNN,C=WW" and will attempt to perform
the entry "CN=Manager,O=MNN,C=WW". It knows that either
LDAP-capable servers (hostb) or (hostc) hold "OU=People,O=MNN,C=WW" (one
is removal requested. The result of the master and delete attempt will be
returned to the other server a shadow), and that LDAP-capable
server (hostd) holds client in the subtree "OU=Roles,O=MNN,C=WW". If a subtree
search of "O=MNN,C=WW" is requested to the contacted server in which
chainingProhibited is set and referrals are permitted, and the filter is
objectClass=*, the server may return the following responses: Delete Response.

Wahl, Howes & Howes, Kille [Page 27] Page 27

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

SearchResultEntry for O=MNN,C=WW
SearchResultEntry for CN=Manager,O=MNN,C=WW
SearchResultReference {
ldap://hostb/OU=People,O=MNN,C=WW
ldap://hostc/OU=People,O=MNN,C=WW
}
SearchResultReference {
ldap://hostd/OU=Roles,O=MNN,C=WW
}
SearchResultDone (entries = 2)

Client implementors should note that when following a
SearchResultReference, additional SearchResultReference may be
generated. Continuing the example, if the client contacted the
server (hostb) and issued the search for the subtree
"OU=People,O=MNN,C=WW", the server might respond as follows:

SearchResultEntry for OU=People,O=MNN,C=WW
SearchResultReference {
ldap://hoste/OU=Managers,OU=People,O=MNN,C=WW
}
SearchResultReference {
ldap://hostf/OU=Consultants,OU=People,O=MNN,C=WW
}

4.6. March 1997

4.9. Modify DN Operation

The Modify DN Operation allows a client to request that a modification change the last component
of the name of an entry be performed on its behalf by in the directory, or to move a server. subtree of
entries to a new location in the directory.
The Modify DN Request is defined as follows:

ModifyRequest

ModifyDNRequest ::= [APPLICATION 6] 12] SEQUENCE {
object
entry LDAPDN,
modification SEQUENCE OF SEQUENCE {
operation ENUMERATED {
add (0),
delete (1),
replace (2) },
modification AttributeTypeAndValues } }

AttributeTypeAndValues ::= SEQUENCE {
type AttributeDescription,
vals SET OF AttributeValue
newrdn RelativeLDAPDN,
deleteoldrdn BOOLEAN,
newSuperior [0] LDAPDN OPTIONAL }

Parameters of the Modify DN Request are:

- object: The object to be modified. The value of this field contains entry: the
DN Distinguished Name of the entry to be modified. The server will changed. This entry
may or may not perform any
alias dereferencing in determining have subordinate entries.

- newrdn: the object to be modified unless RDN that will form the useAliasOnUpdate session control is set to TRUE.

Wahl, Howes & Kille [Page 28]

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

- A list last component of modifications to be performed on the entry to be modified.
The entire list of entry modifications must be performed
in the order they are listed, as new name.

- deleteoldrdn: a single atomic operation. While
individual modifications may violate the directory schema, the
resulting entry after the entire list of modifications is performed
must conform to the requirements of the directory schema. The
values boolean parameter that may be taken on by the 'operation' field in each
modification construct have controls whether the following semantics respectively:

add: add old RDN
attribute values listed are to be retained as attributes of the given attribute, creating
the attribute if necessary;

delete: delete values listed entry, or
deleted from the given attribute,
removing the entire attribute if no values are listed, or entry.

- newSuperior: if all current values of present, this is the attribute are listed for
deletion;

replace: replace all existing values Distinguished Name of the given attribute
with the new values listed, creating entry
which becomes the attribute if it
did not already exist. A replace with no value will delete immediate superior of the entire attribute. existing entry.

The result of the modify name change attempted by the server upon receipt of
a Modify DN Request is returned in a the Modify DN Response, defined
as follows:

ModifyResponse

ModifyDNResponse ::= [APPLICATION 7] 13] LDAPResult

Upon receipt of a Modify Request, ModifyDNRequest, a server will perform the necessary
modifications attempt to
perform the DIT. name change. The server result of the name change attempt will return
be returned to the client a single in the Modify Response
indicating either DN Response.

If the successful completion of deleteoldrdn parameter is TRUE, the DIT modification,
or values forming the reason that old
RDN are deleted from the modification failed. Note that due to entry. If the
requirement for atomicity in applying deleteoldrdn parameter is
FALSE, the list of modifications in values forming the Modify Request, the client may expect that no modifications old RDN will be retained as
non-distinguished attribute values of the DIT have been performed if entry. The server may
not perform the Modify Response received indicates
any sort of error, operation and that all requested modifications have been
performed return an error code if the Modify Response indicates successful completion setting of
the Modify Operation. If the connection fails, whether deleteoldrdn parameter would cause a schema inconsistency in the modification
occurred or not is indeterminate.
entry.

Note that due to X.500 restricts the simplifications made in LDAP, there is not ModifyDN operation to only affect entries
that are contained within a direct
mapping of single server. If the modifications in an LDAP ModifyRequest server is mapped
onto the
EntryModifications of a a DAP ModifyEntry operation, DAP, then this restriction will apply, and different
implementations of LDAP-DAP gateways may use different means of
representing the change. The final effect of the operations on the
entry resultCode
affectsMultipleDSAs will be identical. returned if this error occurred. In general
clients must not expect to be able to perform arbitrary movements of
entries and subtrees between servers.

Wahl, Howes & Howes, Kille [Page 29] Page 28

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

4.7. Add March 1997

4.10. Compare Operation

The Add Compare Operation allows a client to request the addition of compare an assertion
provided with an entry
into in the directory. The Add Compare Request is
defined as follows:

AddRequest

CompareRequest ::= [APPLICATION 8] 14] SEQUENCE {
entry LDAPDN,
attributes AttributeList }

AttributeList ::= SEQUENCE OF SEQUENCE {
type AttributeDescription,
vals SET OF AttributeValue
ava AttributeValueAssertion }

Parameters of the Add Compare Request are:

- entry: the Distinguished Name name of the entry to be added. Note that
all components of the name except for compared with.

- ava: the last RDN component must
exist for assertion with which an attribute in the add to succeed. Note also that the server will not
dereference any aliases in locating the entry entry is to be added (unless
the useAliasOnUpdate session control is TRUE), and that there are
never any entries subordinate to an alias entry.

- attributes: the list of attributes that make up the content of the
entry being added. Clients must included distinguished values in
this list.
compared.

The result of the add compare attempted by the server upon receipt of a Add
Compare Request is returned in the Add Compare Response, defined as
follows:

AddResponse

CompareResponse ::= [APPLICATION 9] 15] LDAPResult

Upon receipt of an Add a Compare Request, a server will attempt to perform
the
add requested. requested comparison. The result of the add attempt comparison will be
returned to the client in the Add Compare Response.

4.8. Delete Note that errors and
the result of comparison are all returned in the same construct.

Note that some directory systems may establish access controls which
permit the values of certain attributes (such as userPassword) to be
compared but not read. In a search result, it may be that an attribute
of that type would be returned, but with an empty set of values.

4.11. Abandon Operation

The Delete function of the Abandon Operation allows is to allow a client to request
that the removal of server abandon an
entry from the directory. outstanding operation. The Delete Abandon
Request is defined as follows:

DelRequest

AbandonRequest ::= [APPLICATION 10] LDAPDN 16] MessageID

The Delete Request consists of the Distinguished Name of the
entry to MessageID MUST be deleted. Note that the server will not dereference aliases
while resolving the name of a an operation which was requested earlier
in this connection.

(The abandon request itself has its own message id. This is distinct
from the target entry to be removed, unless id of the useAliasOnUpdate session control earlier operation being abandoned.)

There is TRUE.

The result no response defined in the Abandon Operation. Upon
transmission of an Abandon Operation, a client may expect that the delete attempted
operation identified by the server upon receipt of Message ID in the Abandon Request has
been abandoned. In the event that a
Delete server receives an Abandon
Request is returned on a Search Operation in the Delete Response, defined as follows:

DelResponse ::= [APPLICATION 11] LDAPResult midst of transmitting
responses to the search, that server MUST cease transmitting entry
responses to the abandoned request immediately, and MUST NOT send the
SearchResponseDone. Of course, the server MUST ensure that only properly
encoded LDAPMessage PDUs are transmitted.

Wahl, Howes & Howes, Kille [Page 30] Page 29

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

Upon receipt of a Delete Request, a server will attempt to perform
the entry removal requested. The result of March 1997

Clients MUST NOT send abandon requests for the delete attempt will same operation multiple
times, and MUST also be
returned prepared to the client receive results from operations it
has abandoned (since these may have been in transit when the Delete Response. Note that only leaf
objects (with no subordinates) may abandon was
requested).

Servers MUST discard abandon requests for message IDs they do not
recognize, for operations which cannot be deleted with this operation.

4.9. Modify DN Operation

The Modify DN abandoned, and for operations
which have already been abandoned.

4.12. Extended Operation allows a client to change the last component
of the name

An extension mechanism has been added in this version of an entry LDAP, in the directory, or order to move a subtree of
entries
allow additional operations to a new location be defined for services not available
elsewhere in the directory. this protocol, for instance digitally signed operations and
results.

The Modify DN Request is extended operation allows clients to make requests and receive
responses with predefined syntaxes and semantics. These may be
defined as follows:

ModifyDNRequest in RFCs or be private to particular implementations. Each
operation MUST have a unique OBJECT IDENTIFIER assigned to it.

ExtendedRequest ::= [APPLICATION 12] 23] SEQUENCE {
entry LDAPDN,
newrdn RelativeLDAPDN,
deleteoldrdn BOOLEAN,
newSuperior
requestName [0] LDAPDN LDAPOID,
requestValue [1] OCTET STRING OPTIONAL }

Parameters of the Modify DN Request are:

- entry: the name

The requestName is a dotted-decimal representation of the entry
OBJECT IDENTIFIER corresponding to be changed.

- newrdn: the RDN request.
The requestValue is information in a form defined by that request,
encapsulated inside an OCTET STRING.

The server will form respond to this with an LDAPMessage containing the last component of
ExtendedResponse.

ExtendedResponse ::= [APPLICATION 24] SEQUENCE {
COMPONENTS OF LDAPResult,
responseName [10] LDAPOID OPTIONAL,
response [11] OCTET STRING OPTIONAL }

If the new name.

- deleteoldrdn: a boolean parameter that controls whether server does not recognize the old RDN
attribute values is to be retained as attributes of request name, it MUST return
only the entry, or
deleted response fields from LDAPResult, containing the entry.

- newSuperior: if present, this is protocolError
result code.

5. Protocol Element Encodings and Transfer

Two underlying services are defined here. At a minimum, clients and
servers SHOULD implement the name mapping of LDAP over TCP described in 5.2.1.

5.1. Mapping Onto BER-based Transport Services

The protocol elements of LDAP are encoded for exchange using the entry which
becomes the immediate superior
Basic Encoding Rules (BER) [11] of ASN.1 [3]. However, due to the existing entry.

The result
high overhead involved in using certain elements of the name change attempted by BER, the server upon receipt
following additional restrictions are placed on BER-encodings of
a Modify DN Request is returned in the Modify DN Response, defined
as follows:

ModifyDNResponse ::= [APPLICATION 13] LDAPResult

Upon receipt of a ModifyDNRequest, a server will attempt to
perform LDAP
protocol elements:

Wahl, Howes, Kille Page 30

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) March 1997

(1) Only the name change. The result definite form of the name change attempt length encoding will be returned to the client used.

(2) OCTET STRINGs will be encoded in the Modify DN Response. The attributes
that make up the old RDN are deleted from the entry, or kept,
depending on primitive form only.

(3) If the setting value of a BOOLEAN type is true, the deleteoldrdn parameter.

Note that X.500 restricts the ModifyDN operation encoding MUST have
its contents octets set to only affect entries
that are contained within a single server. hex "FF".

(4) If the LDAP server a value of a type is mapped
onto DAP, then this restriction will apply, and the resultCode
affectsMultipleDSAs will its default value, it MUST be returned. In general clients must absent.
Only some BOOLEAN and INTEGER types have default values in this
protocol definition.

These restrictions do not
expect to be able apply to perform arbitrary movements ASN.1 types encapsulated inside of entries and subtrees.

Wahl, Howes & Kille [Page 31]

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

4.10. Compare Operation

The Compare Operation allows a client
OCTET STRINGs, such as attribute values, unless otherwise noted.

5.2. Transfer Protocols

This protocol is designed to compare an assertion
provided run over connection-oriented, reliable
transports, with all 8 bits in an entry octet being significant in the directory. data
stream.

5.2.1. Transmission Control Protocol (TCP)

The Compare Request LDAPMessage PDUs are mapped directly onto the TCP bytestream.
It is
defined as follows:

CompareRequest ::= [APPLICATION 14] SEQUENCE {
entry LDAPDN,
ava AttributeValueAssertion }

Parameters of recommended that server implementations running over the Compare Request are:

- entry: TCP MAY
provide a protocol listener on the name assigned port, 389. Servers may
instead provide a listener on a different port number. Clients MUST
support contacting servers on any valid TCP port.

5.2.2. Secure Socket Layer over TCP (SSL)

LDAP is an application protocol which may be carried inside of a
Secure Sockets Layer connection [8]. After establishing the entry to be compared with.

- ava: SSL
connection over TCP, the assertion with which an attribute in LDAPMessage PDUs are mapped directly onto
the entry is bytestream to be
compared.

The result of the compare attempted encoded by SSL. Server implementations running over
SSL/TCP MAY provide a protocol listener on the assigned port for LDAPS,
port 636.

SSL may be used to provide to the server upon receipt the authenticated identity of a
Compare Request is returned in the Compare Response, defined
client, as
follows:

CompareResponse ::= [APPLICATION 15] SEQUENCE {
COMPONENTS OF LDAPResult,
matchedSubtype [9] AttributeDescription OPTIONAL }

When the resultCode is compareTrue a distinguished name, and the matchedSubtype field server MAY use this information
when making access control decisions. This authentication is
permitted to contain the name of unaffected if
the attribute whose client binds and specifies no value
matched the ava in for the Compare operation. Servers which do not
implement attribute hierarchies will omit this element.

Upon receipt of a Compare Request, password nor a server will attempt to perform
the requested comparison. SASL
mechanism. The result of the comparison will be
returned to the client in may override the Compare Response. authentication by binding with a
distinguished name and a non-empty password or a SASL mechanism. Note
that errors and
the result of comparison are all returned in the same construct.

Note that some directory systems may establish access controls which
permit the values of certain attributes (such as userPassword) to be
compared but not read. In a search result, it may be is expected that an attribute future versions of that type would be returned, but with this document will reference
an empty set of values.

4.11. Abandon Operation

The function of the Abandon Operation is to allow a client to request
that the server abandon IETF specification for equivalent transport layer security services,
when one becomes available.

6. Implementation Guidelines

This document describes an outstanding operation. The Abandon
Request is Internet protocol. Terms are defined as follows:

AbandonRequest ::= [APPLICATION 16] MessageID in [10].

6.1. Server Implementations

The MessageID must server MUST be that of a Search or Compare operation
which was requested earlier during this association. Other types capable of
operations cannot be abandoned.

(The abandon request itself has its own message id. This is distinct
from recognizing all the id of mandatory attribute
type names and implement the earlier operation being abandoned.) syntaxes specified in [5]. Servers may also
recognize additional attribute type names.

Wahl, Howes & Howes, Kille [Page 32] Page 31

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

There is no response defined in the Abandon Operation. Upon
transmission of an Abandon Operation, a client may expect March 1997

6.2. Client Implementations

Clients which request referrals MUST ensure that they do not loop
between servers.

They MUST NOT repeatedly contact the
operation identified by the Message ID in same server for the Abandon Request has
been abandoned. In same request
with the event that same target entry name, scope and filter.

Some clients may be using a server receives counter that is incremented each time
referral handling occurs for an Abandon
Request on operation, and these kind of clients MUST
be able to handle a Search Operation in DIT with at least ten layers of naming contexts
between the midst root and a leaf entry.

7. Security Considerations

When used with a connection-oriented transport, this version of transmitting
responses to the search, that server must cease transmitting entry
responses to
protocol provides facilities for the abandoned request immediately. Of course, LDAP v2 authentication mechanism,
simple authentication using a cleartext password, as well as any SASL
mechanism [12].

It is also permitted that the server
must ensure that only properly encoded LDAPMessages are transmitted.

Clients must not send abandon requests for can return its credentials to the same operation multiple
times. Servers must discard abandon requests for message ids
client, if it does
not recognize, for operations chooses to do so.

This document also defines a mapping of LDAP over the Secure Sockets
Layer (SSL), which can provide strong authentication, integrity and
privacy of the connection.

Use of cleartext password is strongly discouraged where the underlying
transport service cannot be abandoned, guarantee confidentiality and for
operations which have already been abandoned.

4.12. Extended Operation

It may be desirable in some communities to define additional operations
for services not available in this protocol, for instance digitally
signed operations and results. Thus an extension mechanism has been
added result in this version
disclosure of LDAP.

The extended operation allows clients the password to make requests and receive
responses unauthorized parties.

When used with predefined syntaxes and semantics. These may be
defined in RFCs or SASL, it should be private to particular implementations. Each
operation must have a unique OBJECT IDENTIFIER assigned to it.

ExtendedRequest ::= [APPLICATION 23] SEQUENCE {
requestName [0] LDAPOID,
requestValue [1] OCTET STRING }

The requestName is a dotted-decimal representation of noted that the
OBJECT IDENTIFIER corresponding to name field of the request.
The requestValue
BindRequest is not protected against modification. Thus if there is information in a form defined by that request,
encapsulated inside an OCTET STRING.

The server will respond to this with an LDAPMessage containing the
ExtendedResponse.

ExtendedResponse ::= [APPLICATION 24] SEQUENCE {
COMPONENTS OF LDAPResult,
responseName [10] LDAPOID OPTIONAL,
response [11] OCTET STRING OPTIONAL }

If
client name (LDAPDN) agreed through the server does not recognize negotiation of the operation name, credentials,
it must return
only the standard response fields, containing takes precedence over any value in the protocolError result
code.

5. Protocol Element Encodings unprotected name field.

Implementations which cache attributes and Transfer

Four underlying services entries obtained via LDAP
MUST ensure that access controls are defined here. At a minimum, clients maintained if that information is
to be provided to multiple clients.

8. Acknowledgements

This document is an update to RFC 1777, by Wengyik Yeong, Tim
Howes, and
servers must implement the mapping Steve Kille. Design ideas included in this document are
based on those discussed in ASID and other IETF Working Groups. The
contributions of LDAP over TCP described individuals in 5.1.1. these working groups is gratefully
acknowledged.

9. Bibliography

[1] ITU-T Rec. X.500, "The Directory: Overview of Concepts, Models and
Service", 1993.

[2] W. Yeong, T. Howes, S. Kille, "Lightweight Directory Access
Protocol", RFC 1777, March 1995.

Wahl, Howes & Howes, Kille [Page 33] Page 32

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

5.1. Mapping Onto BER-based Transport Services

This protocol is designed to run over connection-oriented, reliable
transports, with all 8 bits in an octet being significant in the data
stream.

The protocol elements March 1997

[3] ITU-T Rec. X.680, "Abstract Syntax Notation One (ASN.1) -
Specification of LDAP are encoded for exchange using the Basic Encoding Rules (BER) [11] of ASN.1 [3]. However, due to the
high overhead involved in using certain elements of the BER, the
following additional restrictions are placed on BER-encodings Notation", 1994.

[4] S. Kille, M. Wahl, "A UTF-8 String Representation of Distinguished
Names", INTERNET-DRAFT <draft-ietf-asid-ldapv3-dn-01.txt>.

[5] M. Wahl, A. Coulbeck, T. Howes, S. Kille, W. Yeong, C. Robbins,
"Lightweight X.500 Directory Access Protocol Attribute Syntax
Definitions", INTERNET-DRAFT
<draft-ietf-asid-ldapv3-attributes-04.txt>, March 1997.

[6] ITU-T Rec. X.501, "The Directory: Models", 1993.

[7] T. Berners-Lee, L. Masinter, M. McCahill, "Uniform Resource
Locators (URL)", RFC 1738, Dec. 1994.

[8] A. Freier, P. Karlton, P. Kocher, "The SSL Protocol Version 3.0",
INTERNET-DRAFT <draft-ietf-tls-ssl-version3-00.txt>, Nov. 1996.

[9] T. Howes, M. Smith, "An LDAP
protocol elements:

(1) Only the definite form of length encoding will be used.

(2) OCTET STRINGs will be encoded URL Format", RFC 1959, June 1996.

[10] S. Bradner, "Key words for use in the primitive form only.

(3) If the value of a BOOLEAN type is true, the encoding must have
its contents octets set RFCs to hex "FF".

(4) If a value Indicate Requirement
Levels", INTERNET-DRAFT <draft-bradner-key-words-03.txt>.

[11] ITU-T Rec. X.690, "Specification of a type is its default value, it must be absent.
Only some BOOLEAN and INTEGER types have default values in this
protocol definition.

These restrictions do not apply to ASN.1 types encapsulated inside of
OCTET STRINGs, such as attribute values, unless otherwise noted.

5.1.1. Transmission Control Protocol (TCP)

The LDAPMessage PDUs are mapped directly onto the TCP bytestream.
Server implementations running over the TCP should provide a protocol
listener on the assigned port, 389.

5.1.2. Connection Oriented Transport Service (COTS)

The connection is established. No special use of T-Connect is made.
Each LDAPMessage PDU is mapped directly onto T-Data.

5.1.3. User Datagram Protocol (UDP)

The LDAPMessage PDUs are mapped directly onto UDP datagrams. A datagram
may contain one or more concatenated requests. Only one response datagram
is returned, containing all the responses concatenated together. The only
operations which the client may request are sessionRequest, searchRequest,
compareRequest encoding rules: Basic,
Canonical, and extendedReq. The server may return sessionResponse,
searchResFull, compareResponse Distinguished Encoding Rules", 1994.

[12] J. Meyers, "Simple Authentication and extendedResp. If any of the requests in
an incoming datagram generates an error (a result other than success,
compareTrue or compareFalse), the server should ignore any following
requests in that datagram.

Server implementations running over the UDP should provide Security Layer",
INTERNET-DRAFT <draft-myers-auth-sasl-04.txt>, July 1996.

[13] Universal Multiple-Octet Coded Character Set (UCS) - Architecture
and Basic Multilingual Plane, ISO/IEC 10646-1 : 1993.

[14] F. Yergeau, "UTF-8, a protocol
listener on the assigned port, 389.

Wahl, transformation format of Unicode and ISO
10646", RFC 2044, October 1996.

[15] ITU-T Rec. X.511, "The Directory: Abstract Service Definition",
1993.

10. Authors' Address

Mark Wahl
Critical Angle Inc.
4815 W Braker Lane #502-385
Austin, TX 78759
USA

EMail: M.Wahl@critical-angle.com

Tim Howes &
Netscape Communications Corp.
501 E. Middlefield Rd.
Mountain View, CA 94043
USA

Wahl, Howes, Kille [Page 34] Page 33

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

5.1.4. Secure Socket Layer over TCP (SSL)

LDAP is an application protocol which may be carried inside of an
Secure Sockets Layer connection [8]. After establishing the SSL
connection over TCP, the LDAPMessage PDUs are mapped directly onto
the bytestream. Server implementations running over SSL/TCP should
provide a protocol listener on the assigned port for LDAP-SSL, port 636.

Note: it is expected that future versions of this document may reference
an IETF specification for equivalent transport layer security services,
should one become available.

6. Implementation Guidelines

6.1. Server Implementations

The server must be capable of recognizing all the mandatory attribute
type names and implement the syntaxes specified in [5]. Servers may also
recognize additional attribute type names.

6.2. Client Implementations

6.2.1. CLDAP Retry

For simple lookup applications using the connectionless transport
protocol UDP, use of a retry algorithm with multiple servers similar
to that commonly used in DNS stub resolver implementations is
recommended. The location of a CLDAP server or servers may be better
specified using IP addresses (simple or broadcast) rather than names
that must first be looked up in another directory such as DNS.

6.2.2. Loop Detection

Clients which request referrals must ensure that they do not loop
between servers. They must not progress a referral or reference in a
subtree search where the new name is a superior of the name requested.
They must not repeatedly contact the same server twice with the same
target entry name. Some clients may be using a counter that is
incremented each time referral handling is handled for an operation,
and these kind of clients must be able to handle a DIT with up to ten
layers of naming contexts between the root and a leaf entry.

7. Security Considerations

When used with a connection-oriented transport, this version of the
protocol provides facilities for the LDAP v2 authentication mechanism,
simple authentication using a cleartext password, as well as any SASL
mechanism [17].

It is also permitted that the server can return its credentials to the
client, if it chooses to do so.

Wahl, Howes & Kille [Page 35]

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

This document also defines a mapping of LDAP over the Secure Sockets
Layer (SSL), which can provide strong authentication, integrity and
privacy of the connection.

Use of cleartext password is strongly discouraged where the underlying
transport service cannot guarantee confidentiality. A password hashing
mechanism is given in Appendix B.

When used with SASL, it should be noted that the name field of the
BindRequest is not protected against modification. Thus if there is a
client name (LDAPDN) agreed through the negotiation of the credentials,
it must take precedence over any value in the unprotected name field.

When used with the connectionless transport, no security services are
available. There has been some discussion about the desirability of
authentication with connectionless LDAP requests. This might take the
form of a clear text password (which would go against the current IAB
drive to remove such things from protocols) or some arbitrary
credentials. It is felt that, in general, authentication would incur
sufficient overhead to negate the advantages of the connectionless
basis of LDAP. If an application requires authenticated access to the
directory then connectionless LDAP is not an appropriate protocol.

8. Acknowledgements

This document is an update to RFC 1777, by Wengyik Yeong, Tim
Howes, and Steve Kille. It also includes material from RFC 1798, by
Alan Young. Design ideas included in this document are based on those
discussed in ASID and other IETF Working Groups. The contributions of
individuals in these working groups is gratefully acknowledged.

9. Bibliography

[1] ITU-T Rec. X.500, "The Directory: Overview of Concepts, Models and
Service", 1993.

[2] W. Yeong, T. Howes, S. Kille, "Lightweight Directory Access
Protocol", RFC 1777, March 1995.

[3] ITU-T Rec. X.680, "Abstract Syntax Notation One (ASN.1) -
Specification of Basic Notation", 1994.

[4] S. Kille, M. Wahl, "A UTF-8 String Representation of Distinguished
Names", INTERNET-DRAFT <draft-ietf-asid-ldapv3-dn-00.txt>.

[5] M. Wahl, A. Coulbeck, T. Howes, S. Kille, W. Yeong, C. Robbins,
"Lightweight X.500 Directory Access Protocol Standard and Pilot
Attribute Definitions", INTERNET-DRAFT
<draft-ietf-asid-ldapv3-attributes-02.txt>, August 1996.

[6] ITU-T Rec. X.501, "The Directory: Models", 1993.

[7] ITU-T Rec. X.520, "The Directory: Selected Attribute Types", 1993.

Wahl, Howes & Kille [Page 36]

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

[8] A. Freier, P. Karlton, P. Kocher, "The SSL Protocol Version 3.0",
INTERNET-DRAFT <draft-freier-ssl-version3-01.txt>, March 1996.

[9] T. Howes, M. Smith, "An LDAP URL Format", RFC 1959, June 1996.

[10] ITU-T Rec. X.518, "The Directory: Procedures for Distributed
Operation", 1993.

[11] ITU-T Rec. X.690, "Specification of ASN.1 encoding rules: Basic,
Canonical, and Distinguished Encoding Rules", 1994.

[12] ITU-T Rec. X.509, "The Directory: Authentication Framework",
1993.

[13] ITU-T Rec. X.511, "The Directory: Abstract Service Definition", 1993.

[14] T. Berners-Lee, L. Masinter, M. McCahill, "Uniform Resource
Locators (URL)", RFC 1738, Dec. 1994.

[15] Universal Multiple-Octet Coded Character Set (UCS) - Architecture
and Basic Multilingual Plane, ISO/IEC 10646-1 : 1993.

[16] M. Davis, UTF-8, (WG2 N1036) DAM for ISO/IEC 10646-1.

[17] J. Meyers, "Simple Authentication and Security Layer",
INTERNET-DRAFT <draft-myers-auth-sasl-04.txt>, July 1996.

10. Authors' Address

Mark Wahl
Critical Angle Inc.
4815 W Braker Lane #502-385
Austin, TX 78759
USA

EMail: M.Wahl@critical-angle.com

Tim Howes
Netscape Communications Corp.
501 E. Middlefield Rd.
Mountain View, CA 94043
USA

Phone: +1 415 254-1900
EMail: howes@netscape.com

Wahl, Howes & Kille [Page 37]

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

Steve Kille
ISODE Consortium
The Dome, The Square
Richmond
TW9 1DT
UK

Phone: +44-181-332-9091
EMail: S.Kille@isode.com

Appendix A - Complete ASN.1 Definition

Lightweight-Directory-Access-Protocol-V3 DEFINITIONS
IMPLICIT TAGS ::=

BEGIN

MessageID ::= INTEGER (0 .. maxInt)

maxInt INTEGER ::= 2147483647 -- (2^^31 - 1) --

LDAPString ::= OCTET STRING

LDAPOID ::= OCTET STRING

Wahl, Howes & Kille [Page 38]

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

LDAPDN ::= LDAPString

RelativeLDAPDN ::= LDAPString

AttributeType ::= LDAPString

AttributeDescription ::= LDAPString

AttributeDescriptionList ::= SEQUENCE OF
AttributeDescription

AttributeValue ::= OCTET STRING

AttributeValueAssertion ::= SEQUENCE {
attributeDesc AttributeDescription,
assertionValue AssertionValue }

AssertionValue ::= OCTET STRING

Attribute ::= SEQUENCE {
type AttributeDescription,
vals SET OF AttributeValue }

MatchingRuleId ::= LDAPString

Wahl, Howes & Kille [Page 39]

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

LDAPResult ::= SEQUENCE {
resultCode ENUMERATED {
success (0),
operationsError (1),
protocolError (2),
timeLimitExceeded (3),
sizeLimitExceeded (4),
compareFalse (5),
compareTrue (6),

authMethodNotSupported (7),
strongAuthRequired (8),
-- 9 reserved --
referral (10), -- new
adminLimitExceeded (11), -- new
unavailableCriticalExtension (12), -- new
-- 13-15 unused --
noSuchAttribute (16),
undefinedAttributeType (17),
inappropriateMatching (18),
constraintViolation (19),
attributeOrValueExists (20),
invalidAttributeSyntax (21),
-- 22-31 unused --
noSuchObject (32),
aliasProblem (33),
invalidDNSyntax (34),
-- 35 reserved for undefined isLeaf --
aliasDereferencingProblem (36),
-- 37-47 unused --
inappropriateAuthentication (48),
invalidCredentials (49),
insufficientAccessRights (50),
busy (51),
unavailable (52),
unwillingToPerform (53),
loopDetect (54),
-- 55-63 unused --
namingViolation (64),
objectClassViolation (65),
notAllowedOnNonLeaf (66),
notAllowedOnRDN (67),
entryAlreadyExists (68),
objectClassModsProhibited (69),
resultsTooLarge (70), -- cl only
affectsMultipleDSAs (71), -- new
-- 72-79 unused --
other (80) },
-- 81-90 reserved for APIs --
matchedDN LDAPDN,
errorMessage LDAPString,
referral [3] Referral OPTIONAL }

Referral ::= SEQUENCE OF LDAPURL

Wahl, Howes & Kille [Page 40]

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

LDAPURL ::= LDAPString -- limited to characters permitted in URLs

BindRequest ::= [APPLICATION 0] SEQUENCE {
version INTEGER (1 .. 127),
name LDAPDN,
authentication AuthenticationChoice }

AuthenticationChoice ::= CHOICE {
simple [0] OCTET STRING,
-- 1 and 2 reserved
sasl [3] SaslCredentials }

SaslCredentials ::= SEQUENCE {
mechanism LDAPString,
credentials OCTET STRING }

BindResponse ::= [APPLICATION 1] SEQUENCE {
COMPONENTS OF LDAPResult,
supportedVersion [5] INTEGER (1..127) OPTIONAL,
serverURL [6] LDAPURL OPTIONAL,
serverCreds [7] AuthenticationChoice OPTIONAL }

UnbindRequest ::= [APPLICATION 2] NULL

SessionRequest ::= [APPLICATION 17] Controls

SessionResponse ::= [APPLICATION 18] SEQUENCE {
COMPONENTS OF LDAPResult,
unsupportedCtls [12] SEQUENCE OF LDAPString }

Controls ::= SEQUENCE OF SEQUENCE {
controlType LDAPString,
criticality BOOLEAN DEFAULT FALSE,
controlValue OCTET STRING }

Wahl, Howes & March 1997

Phone: +1 415 254-1900
EMail: howes@netscape.com

Steve Kille [Page 41]

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

SortKeyList ::= SEQUENCE OF SEQUENCE {
attributeType AttributeType,
orderingRule [0] MatchingRuleId OPTIONAL,
reverseOrder [1] BOOLEAN DEFAULT FALSE }

SubstringFilter
Isode Limited
The Dome, The Square
Richmond
TW9 1DT
UK

Phone: +44-181-332-9091
EMail: S.Kille@isode.com

Appendix A - Complete ASN.1 Definition

Lightweight-Directory-Access-Protocol-V3 DEFINITIONS
IMPLICIT TAGS ::= SEQUENCE {
type AttributeDescription,
-- at least one must be present
substrings SEQUENCE OF CHOICE {
initial [0] LDAPString,
any [1] LDAPString,
final [2] LDAPString } }

MatchingRuleAssertion

BEGIN

LDAPMessage ::= SEQUENCE {
matchingRule [1] MatchingRuleId OPTIONAL,
type [2] AttributeType OPTIONAL,
matchValue [3] AssertionValue,
dnAttributes [4] BOOLEAN DEFAULT FALSE }

SearchResultEntry ::= [APPLICATION 4] SEQUENCE
messageID MessageID,
protocolOp CHOICE {
objectName LDAPDN,
attributes PartialAttributeList
bindRequest BindRequest,
bindResponse BindResponse,
unbindRequest UnbindRequest,
searchRequest SearchRequest,
searchResEntry SearchResultEntry,
searchResDone SearchResultDone,
searchResRef SearchResultReference,
modifyRequest ModifyRequest,
modifyResponse ModifyResponse,
addRequest AddRequest,
addResponse AddResponse,
delRequest DelRequest,
delResponse DelResponse,
modDNRequest ModifyDNRequest,
modDNResponse ModifyDNResponse,
compareRequest CompareRequest,
compareResponse CompareResponse,
abandonRequest AbandonRequest,
extendedReq ExtendedRequest,
extendedResp ExtendedResponse },
controls [0] Controls OPTIONAL }

PartialAttributeList

MessageID ::= SEQUENCE OF SEQUENCE {
type AttributeDescription,
vals SET OF AttributeValue }
-- implementors should note that the PartialAttributeList may have
-- zero elements (if none of the attributes of that entry were
-- requested, or could be returned), and that the vals set may also
-- have zero elements (if types only was requested, or all the values INTEGER (0 .. maxInt)

maxInt INTEGER ::= 2147483647 -- exceeded the attribute size limit or were excluded because of (2^^31 - 1) -- access control).

SearchResultReference

LDAPString ::= [APPLICATION 19] SEQUENCE OF LDAPURL
-- at least one LDAPURL element must be present

SearchResultDone OCTET STRING

LDAPOID ::= [APPLICATION 5] SEQUENCE {
COMPONENTS OF LDAPResult,
totalCount [8] INTEGER OPTIONAL } OCTET STRING

LDAPDN ::= LDAPString

Wahl, Howes & Howes, Kille [Page 42] Page 34

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

SearchResultFull March 1997

RelativeLDAPDN ::= SEQUENCE OF CHOICE {
entry SearchResultEntry,
reference SearchResultReference,
resultCode SearchResultDone }

ModifyRequest LDAPString

AttributeType ::= [APPLICATION 6] SEQUENCE {
object LDAPDN,
modification SEQUENCE OF SEQUENCE {
operation ENUMERATED {
add (0),
delete (1),
replace (2) },
modification AttributeTypeAndValues } }

AttributeTypeAndValues LDAPString

AttributeDescription ::= LDAPString

AttributeDescriptionList ::= SEQUENCE {
type AttributeDescription,
vals SET OF
AttributeDescription

AttributeValue }

ModifyResponse ::= [APPLICATION 7] LDAPResult

AddRequest OCTET STRING

AttributeValueAssertion ::= [APPLICATION 8] SEQUENCE {
entry LDAPDN,
attributes AttributeList
attributeDesc AttributeDescription,
assertionValue AssertionValue }

AttributeList

AssertionValue ::= OCTET STRING

Attribute ::= SEQUENCE OF SEQUENCE {
type AttributeDescription,
vals SET OF AttributeValue }

AddResponse ::= [APPLICATION 9] LDAPResult

DelRequest ::= [APPLICATION 10] LDAPDN

DelResponse ::= [APPLICATION 11] LDAPResult

ModifyDNRequest ::= [APPLICATION 12] SEQUENCE {
entry LDAPDN,
newrdn RelativeLDAPDN,
deleteoldrdn BOOLEAN,
newSuperior [0] LDAPDN OPTIONAL }

ModifyDNResponse

MatchingRuleId ::= [APPLICATION 13] LDAPString

LDAPResult

CompareRequest ::= [APPLICATION 14] SEQUENCE {
entry LDAPDN,
ava AttributeValueAssertion }

CompareResponse ::= [APPLICATION 15] SEQUENCE {
COMPONENTS OF LDAPResult,
matchedSubtype [9] AttributeDescription OPTIONAL }

AbandonRequest ::= [APPLICATION 16] MessageID

ExtendedRequest ::= [APPLICATION 23] SEQUENCE
resultCode ENUMERATED {
requestName [0] LDAPOID,
requestValue [1] OCTET STRING }
success (0),
operationsError (1),
protocolError (2),
timeLimitExceeded (3),
sizeLimitExceeded (4),
compareFalse (5),
compareTrue (6),
authMethodNotSupported (7),
strongAuthRequired (8),
-- 9 reserved --
referral (10), -- new
adminLimitExceeded (11), -- new
unavailableCriticalExtension (12), -- new
-- 13-15 unused --
noSuchAttribute (16),
undefinedAttributeType (17),
inappropriateMatching (18),
constraintViolation (19),
attributeOrValueExists (20),
invalidAttributeSyntax (21),
-- 22-31 unused --
noSuchObject (32),
aliasProblem (33),
invalidDNSyntax (34),
-- 35 reserved for undefined isLeaf --
aliasDereferencingProblem (36),
-- 37-47 unused --
inappropriateAuthentication (48),
invalidCredentials (49),
insufficientAccessRights (50),
busy (51),

Wahl, Howes & Howes, Kille [Page 43] Page 35

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

ExtendedResponse March 1997

unavailable (52),
unwillingToPerform (53),
loopDetect (54),
-- 55-63 unused --
namingViolation (64),
objectClassViolation (65),
notAllowedOnNonLeaf (66),
notAllowedOnRDN (67),
entryAlreadyExists (68),
objectClassModsProhibited (69),
-- 70 reserved for CLDAP --
affectsMultipleDSAs (71), -- new
-- 72-79 unused --
other (80) },
-- 81-90 reserved for APIs --
matchedDN LDAPDN,
errorMessage LDAPString,
referral [3] Referral OPTIONAL }

Referral ::= SEQUENCE OF LDAPURL

LDAPURL ::= LDAPString -- limited to characters permitted in URLs

Controls ::= [APPLICATION 24] SEQUENCE {
COMPONENTS OF LDAPResult,
responseName [10] LDAPOID OPTIONAL,
response [11] Control

Control ::= SEQUENCE {
controlType LDAPOID,
criticality BOOLEAN DEFAULT FALSE,
controlValue OCTET STRING OPTIONAL }

-- not part of LDAP core protocol, see Appendix B --

ProtectedPassword

BindRequest ::= [APPLICATION 0] SEQUENCE {
time1
version INTEGER (1 .. 127),
name LDAPDN,
authentication AuthenticationChoice }

AuthenticationChoice ::= CHOICE {
simple [0] UTCTime OPTIONAL,
time2 [1] UTCTime OPTIONAL,
random1 [2] BIT STRING OPTIONAL,
random2 OCTET STRING,
-- 1 and 2 reserved
sasl [3] BIT STRING OPTIONAL,
algorithmIdentifier [4] LDAPOID,
encipheredPassword [5] BIT STRING SaslCredentials }

StrongCredentials

SaslCredentials ::= SEQUENCE {
certification-path [0] AF.CertificationPath OPTIONAL,
bind-token [1] DAS.Token }

END

Appendix B - X.500 Authentication Mechanisms

This Appendix defines two SASL authentication mechanisms which may
be used with LDAP. These mechanisms are only for authentication, they
have no effect on the protocol encodings and are not designed to
provide integrity or confidentiality services.

If an implementation supports these elements, then the following
additional encoding restrictions apply to these elements:

- BIT STRING values are to be encoded in primitive form only. Unused bits
in the final octet of the encoding of a BIT STRING value, if there are
any, should always be set to zero.

- UTC Times must be encoded with the "Z" suffix, not as a local time.

The client may include one of these mechanisms and its credential in the
BindRequest. The server will return a BindResponse of either:
- success, and the serverCreds field absent, implying that the server
successfully authenticated the client but is not returning any
authentication information about the server,
- success, and the serverCreds field present, with the same
mechanism
as that requested by the client, and the LDAPString,
credentials of the server
itself,
- any of the resultCodes listen in 4.2.3, with the OCTET STRING }

BindResponse ::= [APPLICATION 1] SEQUENCE {
COMPONENTS OF LDAPResult,
serverCreds field
absent, indicating that the server did not successfully authenticate
the client or another problem occurred. [7] SaslCredentials OPTIONAL }

UnbindRequest ::= [APPLICATION 2] NULL

Wahl, Howes & Howes, Kille [Page 44] Page 36

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

B.1. X.511-Protected

The "X.511-Protected" authentication mechanism allows a hash of the
password, combined optionally with the current time March 1997

Filter ::= CHOICE {
and random
numbers, to be sent to [0] SET OF Filter,
or returned from the server. The protected field
contains the hash value. This prevents a password from being carried in
the clear.

The mechanism field is set to the string "X.511-Protected", and the
credentials field contain the DER encoding of a value of the following
ASN.1 type:

ProtectedPassword [1] SET OF Filter,
not [2] Filter,
equalityMatch [3] AttributeValueAssertion,
substrings [4] SubstringFilter,
greaterOrEqual [5] AttributeValueAssertion,
lessOrEqual [6] AttributeValueAssertion,
present [7] AttributeDescription,
approxMatch [8] AttributeValueAssertion,
extensibleMatch [9] MatchingRuleAssertion }

SubstringFilter ::= SEQUENCE {
type AttributeDescription,
-- at least one must be present
substrings SEQUENCE OF CHOICE {
initial [0] LDAPString,
any [1] LDAPString,
final [2] LDAPString } }

MatchingRuleAssertion ::= SEQUENCE {
matchingRule [1] MatchingRuleId OPTIONAL,
type [2] AttributeDescription OPTIONAL,
matchValue [3] AssertionValue,
dnAttributes [4] BOOLEAN DEFAULT FALSE }

SearchResultEntry ::= [APPLICATION 4] SEQUENCE {
objectName LDAPDN,
attributes PartialAttributeList }

PartialAttributeList ::= SEQUENCE OF SEQUENCE {
type AttributeDescription,
vals SET OF AttributeValue }

SearchResultReference ::= [APPLICATION 19] SEQUENCE OF LDAPURL

SearchResultDone ::= [APPLICATION 5] LDAPResult

Wahl, Howes, Kille Page 37

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) March 1997

ModifyRequest ::= [APPLICATION 6] SEQUENCE {
object LDAPDN,
modification SEQUENCE OF SEQUENCE {
operation ENUMERATED {
add (0),
delete (1),
replace (2) },
modification AttributeTypeAndValues } }

AttributeTypeAndValues ::= SEQUENCE {
type AttributeDescription,
vals SET OF AttributeValue }

ModifyResponse ::= [APPLICATION 7] LDAPResult

AddRequest ::= [APPLICATION 8] SEQUENCE {
entry LDAPDN,
attributes AttributeList }

AttributeList ::= SEQUENCE OF SEQUENCE {
type AttributeDescription,
vals SET OF AttributeValue }

AddResponse ::= [APPLICATION 9] LDAPResult

DelRequest ::= [APPLICATION 10] LDAPDN

DelResponse ::= [APPLICATION 11] LDAPResult

ModifyDNRequest ::= [APPLICATION 12] SEQUENCE {
time1
entry LDAPDN,
newrdn RelativeLDAPDN,
deleteoldrdn BOOLEAN,
newSuperior [0] UTCTime OPTIONAL,
time2 [1] UTCTime OPTIONAL,
random1 [2] BIT STRING OPTIONAL,
random2 [3] BIT STRING OPTIONAL,
algorithmIdentifier [4] LDAPOID,
encipheredPassword [5] BIT STRING LDAPDN OPTIONAL }

The use of the time1, time2, random1, random2 and encryptedPassword fields
are as defined in ITU-T Rec. X.509 [12] and the functional profile for X.500
for the environment in which this authentication mechanism is to be used.

The name field of the BindRequest must be a nonempty string when this
mechanism is being used to authenticate the client. Note that this
security mechanism is not intended to protect against attackers
modifying the bind name field or other protocol elements.

B.2. X.511-Strong

Strong authentication to the directory can be accomplished using the
"X.511-Strong".

The mechanism field is set to the string "X.511-Strong", and the
credentials field set to a DER-encoding of a value of the following
ASN.1 type:

StrongCredentials

ModifyDNResponse ::= [APPLICATION 13] LDAPResult

CompareRequest ::= [APPLICATION 14] SEQUENCE {
entry LDAPDN,
ava AttributeValueAssertion }

CompareResponse ::= [APPLICATION 15] LDAPResult

AbandonRequest ::= [APPLICATION 16] MessageID

ExtendedRequest ::= [APPLICATION 23] SEQUENCE {
requestName [0] LDAPOID,
requestValue [1] OCTET STRING OPTIONAL }

ExtendedResponse ::= [APPLICATION 24] SEQUENCE {
certification-path [0] AF.CertificationPath
COMPONENTS OF LDAPResult,
responseName [10] LDAPOID OPTIONAL,
bind-token [1] DAS.Token
response [11] OCTET STRING OPTIONAL }

The ASN.1 type "CertificationPath" is defined in [12], and the ASN.1
type "Token" is defined in [13].

When the credentials are being used to authenticate the client, it is
recommended that the certification-path field be present, which will
contain minimally the client's certificate. If the certification-path
field is supplied, then the name field of the BindRequest must be an
empty string, and the server will obtain the name of the client from
the subject field of the certification-path userCertificate.

END

Wahl, Howes & Howes, Kille [Page 45] Page 38

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

It is recommended for interoperability that if the server's or client's
certificates contain RSA public keys, the PKCS md5WithRSAEncryption
(1.2.840.113549.1.1.4) algorithm should be used. March 1997

Table of Contents

1. Status of this Memo .................................... 1
2. Abstract ............................................... 1
3. Models ................................................. 2
3.1. Protocol Model ........................................ 2
3.2. Data Model ............................................ 3
3.2.1 2
3.2.1. Attributes of Entries ................................ ............................... 3
3.2.2
3.2.2. Subschema Subentry Entries ................................... 4
3.3. Relationship to X.500 ................................. 5
3.4. Server-specific Data Requirements ..................... 5
4. Elements of Protocol ................................... 6
4.1. Common Elements ....................................... 6
4.1.1. Message Envelope .................................... 6
4.1.1.1. Message ID ........................................ 7
4.1.2. String Types ........................................ 8
4.1.3. Distinguished Name and Relative Distinguished Name .. 8
4.1.4. Attribute Type and Description ...................... ...................................... 9
4.1.5. Attribute Value Description ............................... 9
4.1.5.1. Binary Option ..................................... 10
4.1.6. Attribute Value ..................................... 10
4.1.7. Attribute Value Assertion ........................... 11
4.1.7.
4.1.8. Attribute ........................................... 11
4.1.8.
4.1.9. Matching Rule Identifier ............................ 11
4.1.9. 12
4.1.10. Result Message ...................................... 11
4.1.10. ..................................... 12
4.1.11. Referral ........................................... 13 14
4.1.12. Controls ........................................... 15
4.2. Bind Operation ....................................... 14 ........................................ 16
4.2.1. Sequencing of the Bind Request ...................... 15
4.2.2 17
4.2.2. Authentication and Other Security Services ........... 15 .......... 17
4.2.3. Bind Response ....................................... 16 18
4.3. Unbind Operation ..................................... 17 ...................................... 18
4.4. Session Control Operation ............................ 17 Unsolicited Notification .............................. 19
4.4.1. Notice of Disconnection ............................. 19
4.5. Search Operation ..................................... ...................................... 20
4.5.1. Search Request ...................................... 20
4.5.2. Search Result ....................................... 24 23
4.5.3. Continuation References in the Search Result ........ 26 24
4.5.3.1. Example ........................................... 27 24
4.6. Modify Operation ..................................... 28 ...................................... 25
4.7. Add Operation ........................................ 30 ......................................... 27
4.8. Delete Operation ..................................... 30 ...................................... 27
4.9. Modify DN Operation .................................. 31 ................................... 28
4.10. Compare Operation ................................... 32 .................................... 29
4.11. Abandon Operation ................................... 32 .................................... 29
4.12. Extended Operation .................................. 33 ................................... 30
5. Protocol Element Encodings and Transfer ................ 33 30
5.1. Mapping Onto BER-based Transport Services ............ 34
5.1.1. ............. 30
5.2. Transfer Protoocols ................................... 31
5.2.1. Transmission Control Protocol (TCP) ................ 34
5.1.2. Connection Oriented Transport Service (COTS) ....... 34
5.1.3. User Datagram Protocol (UDP) ....................... 34
5.1.4. ................. 31
5.2.2. Secure Socket Layer over TCP (SSL) ................. 35 .................. 31
6. Implementation Guidelines .............................. 35 31
6.1. Server Implementations ............................... 35 ................................ 31
6.2. Client Implementations ................................ 32

Wahl, Howes & Howes, Kille [Page 46] Page 39

INTERNET-DRAFT Lightweight Directory Access Protocol (v3) October 1996

6.2. Client Implementations ............................... 35
6.2.1. CLDAP Retry ......................................... 35
6.2.2. Loop Detection ...................................... 35 March 1997

7. Security Considerations ................................ 35 32
8. Acknowledgements ....................................... 36 32
9. Bibliography ........................................... 36 32
10. Authors' Address ...................................... 37 ....................................... 33
Appendix A - Complete ASN.1 Definition ..................... 38
Appendix B - X.500 Authentication Mechanisms ............... 44
B.1. X.511-Protected ....................................... 45
B.2. X.511-Strong .......................................... 45

<draft-ietf-asid-ldapv3-protocol-03.txt> 34

<draft-ietf-asid-ldapv3-protocol-04.txt> Expires: April 5, September 25, 1997 [Page 47]

----