RFC 2252
Lightweight Directory Access Protocol (v3): Attribute Syntax Definitions
Lightweight Directory Access Protocol (v3): Attribute Syntax Definitions 🎀
Part 1 of 5 🦋
Okay bestie, here's the title block first 💖
- RFC: 2252
- Working group: Network Working Group
- Category: Standards Track
- Date: December 1997
- Authors: M. Wahl (Critical Angle Inc.), A. Coulbeck (Isode Inc.), T. Howes (Netscape Communications Corp.), S. Kille (Isode Limited)
- Obsoletes / Updates: the title block doesn't list anything it obsoletes or updates, so nothing to see here 💅
1. Status of this Memo 💖
This doc is an Internet standards track protocol for the Internet community, and it's asking for discussion and suggestions for improvements 🫶. For the standardization state and status of this protocol, check the current edition of "Internet Official Protocol Standards" (STD 1). Distribution of this memo is unlimited.
Copyright Notice 🌸
Copyright (C) The Internet Society (1997). All Rights Reserved.
IESG Note 🔥
Heads up, this doc describes a directory access protocol that gives you both read and update access. Update access needs secure authentication, but this doc doesn't mandate implementing any satisfactory authentication mechanisms 🙈
The IESG is approving this as a Proposed Standard anyway, per RFC 2026, section 4.4.1, for these reasons:
- a. to encourage implementation and interoperability testing of these protocols (with or without update access) before they are deployed, and
- b. to encourage deployment and use of these protocols in read-only applications. (e.g. applications where LDAPv3 is used as a query language for directories which are updated by some secure mechanism other than LDAP), and
- c. to avoid delaying the advancement and deployment of other Internet standards-track protocols which require the ability to query, but not update, LDAPv3 directory servers.
Readers, consider this your warning ⚠️: until mandatory authentication mechanisms are standardized, clients and servers written to this specification that use update functionality are UNLIKELY TO INTEROPERATE, or MAY INTEROPERATE ONLY IF AUTHENTICATION IS REDUCED TO AN UNACCEPTABLY WEAK LEVEL.
Implementors are also discouraged from deploying LDAPv3 clients or servers that implement the update functionality, until a Proposed Standard for mandatory authentication in LDAPv3 has been approved and published as an RFC 😭
2. Abstract ✨
Okay so the Lightweight Directory Access Protocol (LDAP) [1] needs the contents of AttributeValue fields in protocol elements to be octet strings 🧚. This document defines a set of syntaxes for LDAPv3, plus the rules for how attribute values of those syntaxes get represented as octet strings for transmission in the LDAP protocol. The syntaxes defined here are referenced by this doc and other docs that define attribute types. This document also defines the set of attribute types which LDAP servers should support.
3. Overview 🦋
This document sets up the framework for developing schemas for directories accessible via the Lightweight Directory Access Protocol.
Schema is the collection of attribute type definitions, object class definitions and other information. A server uses it to decide how to match a filter or attribute value assertion (in a compare operation) against the attributes of an entry, and whether to permit add and modify operations 👑
Section 4 states the general requirements and notations for attribute types, object classes, syntax and matching rule definitions. Section 5 lists attributes, section 6 syntaxes and section 7 object classes. Additional documents define schemas for representing real-world objects as directory entries.
4. General Issues 🌈
This document describes encodings used in an Internet protocol.
Quick note on the vocab: the key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [4] 💜
Attribute Type and Object Class definitions are written as a string representation of the AttributeTypeDescription and ObjectClassDescription data types defined in X.501(93) [3]. Implementors are strongly advised to read how schema is represented in X.500 first, before reading the rest of this document 🤓
4.1. Common Encoding Aspects 💜
For defining the encoding rules for attribute syntaxes, we're using the following BNF definitions. They're based on the BNF styles of RFC 822 [13].
a = "a" / "b" / "c" / "d" / "e" / "f" / "g" / "h" / "i" /
"j" / "k" / "l" / "m" / "n" / "o" / "p" / "q" / "r" /
"s" / "t" / "u" / "v" / "w" / "x" / "y" / "z" / "A" /
"B" / "C" / "D" / "E" / "F" / "G" / "H" / "I" / "J" /
"K" / "L" / "M" / "N" / "O" / "P" / "Q" / "R" / "S" /
"T" / "U" / "V" / "W" / "X" / "Y" / "Z"
d = "0" / "1" / "2" / "3" / "4" /
"5" / "6" / "7" / "8" / "9"
hex-digit = d / "a" / "b" / "c" / "d" / "e" / "f" /
"A" / "B" / "C" / "D" / "E" / "F"
k = a / d / "-" / ";"
p = a / d / """ / "(" / ")" / "+" / "," /
"-" / "." / "/" / ":" / "?" / " "
letterstring = 1*a
numericstring = 1*d
anhstring = 1*k
keystring = a [ anhstring ]
printablestring = 1*p
space = 1*" "
whsp = [ space ]
utf8 = <any sequence of octets formed from the UTF-8 [9]
transformation of a character from ISO10646 [10]>
dstring = 1*utf8
qdstring = whsp "'" dstring "'" whsp
qdstringlist = [ qdstring *( qdstring ) ]
qdstrings = qdstring / ( whsp "(" qdstringlist ")" whsp )In the BNF below for the string representation of OBJECT IDENTIFIERs, descr is the syntactic representation of an object descriptor. That's letters and digits, starting with a letter. An OBJECT IDENTIFIER in the numericoid format should not have leading zeroes (so 0.9.3 is fine, but 0.09.3 should not be generated) 🍓
When encoding oid elements in a value, the descr encoding option SHOULD be used in preference to the numericoid. An object descriptor is a more readable alias for a number OBJECT IDENTIFIER, and these (where assigned and known by the implementation) SHOULD be used in preference to numeric oids to the greatest extent possible. Examples of object descriptors in LDAP are attribute type, object class and matching rule names ✨
oid = descr / numericoid
descr = keystring
numericoid = numericstring *( "." numericstring )
woid = whsp oid whsp
; set of oids of either form
oids = woid / ( "(" oidlist ")" )
oidlist = woid *( "$" woid )
; object descriptors used as schema element names
qdescrs = qdescr / ( whsp "(" qdescrlist ")" whsp )
qdescrlist = [ qdescr *( qdescr ) ]
qdescr = whsp "'" descr "'" whsp4.2. Attribute Types ⭐
The attribute types are described by sample values for the subschema "attributeTypes" attribute, which is written in the AttributeTypeDescription syntax. Lines have been folded for readability, but the values transferred in protocol would not contain newlines 🎀
The AttributeTypeDescription is encoded according to the BNF below. The productions for oid, qdescrs and qdstring are in section 4.1. Implementors should note that future versions of this document may have expanded this BNF to include additional terms. Terms which begin with the characters X- are reserved for private experiments, and MUST be followed by a <qdstrings> 🧪
AttributeTypeDescription = "(" whsp
numericoid whsp ; AttributeType identifier
[ "NAME" qdescrs ] ; name used in AttributeType
[ "DESC" qdstring ] ; description
[ "OBSOLETE" whsp ]
[ "SUP" woid ] ; derived from this other
; AttributeType
[ "EQUALITY" woid ; Matching Rule name
[ "ORDERING" woid ; Matching Rule name
[ "SUBSTR" woid ] ; Matching Rule name
[ "SYNTAX" whsp noidlen whsp ] ; see section 4.3
[ "SINGLE-VALUE" whsp ] ; default multi-valued
[ "COLLECTIVE" whsp ] ; default not collective
[ "NO-USER-MODIFICATION" whsp ]; default user modifiable
[ "USAGE" whsp AttributeUsage ]; default userApplications
whsp ")"
AttributeUsage =
"userApplications" /
"directoryOperation" /
"distributedOperation" / ; DSA-shared
"dSAOperation" ; DSA-specific, value depends on serverServers are not required to provide the same text, or any text at all, in the description part of the subschema values they maintain 🙃 Servers SHOULD provide at least one of the SUP and SYNTAX fields for each AttributeTypeDescription.
Servers MUST implement all the attribute types referenced in sections 5.1, 5.2 and 5.3 💅
Servers MAY recognize additional names and attributes that aren't listed in this document. If they do, they MUST publish the definitions of those types in the attributeTypes attribute of their subschema entries 🌟
Schema developers MUST NOT create attribute definitions whose names conflict with attributes defined for use with LDAP in existing standards-track RFCs. Do not be that person 💀
An AttributeDescription can be used as the value in a NAME part of an AttributeTypeDescription. Note that these are case insensitive 🌸
Also, the AttributeTypeDescription doesn't list the matching rules that can be used with that attribute type in an extensibleMatch search filter. That's handled by the matchingRuleUse attribute, described in section 4.5 🦋
This document refines the schema description of X.501 by requiring that the syntax field in an AttributeTypeDescription be a string representation of an OBJECT IDENTIFIER for the LDAP string syntax definition, plus an optional indication of the maximum length of a value of this attribute (defined in section 4.3.2) 💜
4.3. Syntaxes ✨
okay bestie, this section is all about the rules every attribute syntax encoding has to follow 💅 Anyone writing a new one is expected to play by these, no exceptions 🫶
The encoding rules for a syntax have to produce octet strings. Where possible, those octet strings should be usable in their native encoded form for display 🌸 Like, for syntaxes holding non-binary values, the output should be displayable by LDAP clients with little or no translation. The catch is that some things (audio is the classic example 🎧) just don't have a sensible printable form, so clients MUST NOT assume that an unrecognized syntax is a string representation 🙈
There's also a little escaping situation 🧚 If an arbitrary string that isn't a Distinguished Name gets used inside a bigger production, a backslash quoting mechanism escapes the separator characters (things like ', $ or #). The backslash is followed by two hex digits for the character. A backslash sitting in that string is always sent as \5C or \5c 💜 There's an example of this in section 6.27.
Last thing: syntaxes can also be defined for matching rules whose assertion value syntax is different from the attribute value syntax ✨
4.3.1 Binary Transfer of Values
this one's for when the client asks for binary encoding of an attribute, or when the attribute syntax name is "1.3.6.1.4.1.1466.115.121.1.5" 🦋 The LDAP AttributeValue or AssertionValue field holds a BER-encoded instance of the attribute value (or matching rule assertion value) ASN.1 data type from X.500. The first byte inside the OCTET STRING wrapper is a tag octet, but the OCTET STRING itself is still in primitive form 🔥
Here's the big rule 👑 All servers MUST implement this form for generating attribute values in search responses, and for parsing attribute values in add, compare and modify requests, as long as the attribute type is recognized and the attribute syntax name is Binary. Clients that ask for all attributes back from entries MUST be ready to get values in binary (think userCertificate;binary 🔐). They SHOULD NOT just display binary or unrecognized values to users, because that's a whole mess 💀
4.3.2. Syntax Object Identifiers
syntaxes are named by OBJECT IDENTIFIERs, which are dotted-decimal strings 🔢 They aren't meant to be shown to users, so don't worry about making them pretty 😭
noidlen = numericoid [ "{" len "}" ]
len = numericstringHere's the table of syntaxes defined for LDAP so far 💖 The H-R column is a hint about whether a value in that syntax would likely be a human readable string. Clients and servers don't have to implement every syntax listed here, and they MAY implement other syntaxes too 🌈
Other documents can define more syntaxes, but defining extra arbitrary ones is strongly deprecated 🚫 Why? Because it hurts interoperability. Current client and server implementations generally can't dynamically recognize new syntaxes, so it's a big no-no 🙅 Most of the time, attributes just get defined with the syntax for directory strings 🎀
Value being represented H-R OBJECT IDENTIFIER
=================================================================
ACI Item N 1.3.6.1.4.1.1466.115.121.1.1
Access Point Y 1.3.6.1.4.1.1466.115.121.1.2
Attribute Type Description Y 1.3.6.1.4.1.1466.115.121.1.3
Audio N 1.3.6.1.4.1.1466.115.121.1.4
Binary N 1.3.6.1.4.1.1466.115.121.1.5
Bit String Y 1.3.6.1.4.1.1466.115.121.1.6
Boolean Y 1.3.6.1.4.1.1466.115.121.1.7
Certificate N 1.3.6.1.4.1.1466.115.121.1.8
Certificate List N 1.3.6.1.4.1.1466.115.121.1.9
Certificate Pair N 1.3.6.1.4.1.1466.115.121.1.10
Country String Y 1.3.6.1.4.1.1466.115.121.1.11
DN Y 1.3.6.1.4.1.1466.115.121.1.12
Data Quality Syntax Y 1.3.6.1.4.1.1466.115.121.1.13
Delivery Method Y 1.3.6.1.4.1.1466.115.121.1.14
Directory String Y 1.3.6.1.4.1.1466.115.121.1.15
DIT Content Rule Description Y 1.3.6.1.4.1.1466.115.121.1.16
DIT Structure Rule Description Y 1.3.6.1.4.1.1466.115.121.1.17
DL Submit Permission Y 1.3.6.1.4.1.1466.115.121.1.18
DSA Quality Syntax Y 1.3.6.1.4.1.1466.115.121.1.19
DSE Type Y 1.3.6.1.4.1.1466.115.121.1.20
Enhanced Guide Y 1.3.6.1.4.1.1466.115.121.1.21
Facsimile Telephone Number Y 1.3.6.1.4.1.1466.115.121.1.22
Fax N 1.3.6.1.4.1.1466.115.121.1.23
Generalized Time Y 1.3.6.1.4.1.1466.115.121.1.24
Guide Y 1.3.6.1.4.1.1466.115.121.1.25
IA5 String Y 1.3.6.1.4.1.1466.115.121.1.26
INTEGER Y 1.3.6.1.4.1.1466.115.121.1.27
JPEG N 1.3.6.1.4.1.1466.115.121.1.28
LDAP Syntax Description Y 1.3.6.1.4.1.1466.115.121.1.54
LDAP Schema Definition Y 1.3.6.1.4.1.1466.115.121.1.56
LDAP Schema Description Y 1.3.6.1.4.1.1466.115.121.1.57
Master And Shadow Access Points Y 1.3.6.1.4.1.1466.115.121.1.29
Matching Rule Description Y 1.3.6.1.4.1.1466.115.121.1.30
Matching Rule Use Description Y 1.3.6.1.4.1.1466.115.121.1.31
Mail Preference Y 1.3.6.1.4.1.1466.115.121.1.32
MHS OR Address Y 1.3.6.1.4.1.1466.115.121.1.33
Modify Rights Y 1.3.6.1.4.1.1466.115.121.1.55
Name And Optional UID Y 1.3.6.1.4.1.1466.115.121.1.34
Name Form Description Y 1.3.6.1.4.1.1466.115.121.1.35
Numeric String Y 1.3.6.1.4.1.1466.115.121.1.36
Object Class Description Y 1.3.6.1.4.1.1466.115.121.1.37
Octet String Y 1.3.6.1.4.1.1466.115.121.1.40
OID Y 1.3.6.1.4.1.1466.115.121.1.38
Other Mailbox Y 1.3.6.1.4.1.1466.115.121.1.39
Postal Address Y 1.3.6.1.4.1.1466.115.121.1.41
Protocol Information Y 1.3.6.1.4.1.1466.115.121.1.42
Presentation Address Y 1.3.6.1.4.1.1466.115.121.1.43
Printable String Y 1.3.6.1.4.1.1466.115.121.1.44
Substring Assertion Y 1.3.6.1.4.1.1466.115.121.1.58
Subtree Specification Y 1.3.6.1.4.1.1466.115.121.1.45
Supplier Information Y 1.3.6.1.4.1.1466.115.121.1.46
Supplier Or Consumer Y 1.3.6.1.4.1.1466.115.121.1.47
Supplier And Consumer Y 1.3.6.1.4.1.1466.115.121.1.48
Supported Algorithm N 1.3.6.1.4.1.1466.115.121.1.49
Telephone Number Y 1.3.6.1.4.1.1466.115.121.1.50
Teletex Terminal Identifier Y 1.3.6.1.4.1.1466.115.121.1.51
Telex Number Y 1.3.6.1.4.1.1466.115.121.1.52
UTC Time Y 1.3.6.1.4.1.1466.115.121.1.53Now, the size hint 📏 You can suggest a minimum upper bound on the number of characters in a value (for string-based syntaxes), or on the number of bytes (for everything else). You do this by appending the count in curly braces after the syntax's OBJECT IDENTIFIER in an Attribute Type Description. This bound isn't part of the syntax name itself, so don't mix them up 🙃 For example, "1.3.6.4.1.1466.0{64}" suggests that server implementations should allow a 64-character string, though they may allow longer ones 💅 And heads up: one character of the Directory String syntax can take more than one byte, since UTF-8 is variable-length 🌏
4.3.3. Syntax Description
this BNF lets you attach a short description to a syntax OBJECT IDENTIFIER 🏷️ Implementors, take note: future versions of this document might expand the definition with extra terms 👀 Terms whose identifier starts with "X-" are reserved for private experiments, and they MUST be followed by a <qdstrings>.
SyntaxDescription = "(" whsp
numericoid whsp
[ "DESC" qdstring ]
whsp ")"4.4. Object Classes
okay, object classes 🧸 The way object classes are represented is defined in X.501 [3]. Basically every entry has an abstract class ("top" or "alias"), at least one structural object class, and zero or more auxiliary object classes. Whether a class is abstract, structural or auxiliary gets decided when its identifier is assigned 🎯 Object class definitions SHOULD NOT be changed without giving them a new identifier 🙏
Object class descriptions follow this BNF:
ObjectClassDescription = "(" whsp
numericoid whsp ; ObjectClass identifier
[ "NAME" qdescrs ]
[ "DESC" qdstring ]
[ "OBSOLETE" whsp ]
[ "SUP" oids ] ; Superior ObjectClasses
[ ( "ABSTRACT" / "STRUCTURAL" / "AUXILIARY" ) whsp ]
; default structural
[ "MUST" oids ] ; AttributeTypes
[ "MAY" oids ] ; AttributeTypes
whsp ")"Same deal as before, implementors: future versions might add more terms 🌸 Terms starting with "X-" are for private experiments, and they MUST be followed by a <qdstrings> encoding 🧪
These are sample values for the subschema "objectClasses" attribute of a server running the LDAP schema. The lines got folded so they're easier to read 📖 Over the wire, though, the values won't contain newlines 💜
Servers SHOULD implement all the object classes referenced in section 7, except for extensibleObject, which is optional ✨ Servers MAY implement extra object classes that aren't listed in this document. If they do, they MUST publish those definitions in the objectClasses attribute of their subschema entries 🦋
Last but not least, schema developers MUST NOT create object class definitions whose names clash with attributes already defined for use with LDAP in existing standards-track RFCs 🚫💖
4.5. Matching Rules 💅
okay so matching rules are how servers actually compare stuff 👀 During Search and Compare ops, servers check attribute values against assertion values using them. They also decide which value to add or delete when someone modifies an entry, and they get used when a purported distinguished name is compared with an entry's name ✨
Most of the attributes in this doc have an equality matching rule defined, which is lowkey so helpful 🦋
The matching rule descriptions get written in this BNF (it's giving formal, I know 🙈). Heads up: future versions of this doc might expand the BNF with more terms, so don't lock anything in. Terms whose identifier starts with X- are reserved for private experiments, and they MUST be followed by a <qdstrings> encoding 🔥
MatchingRuleDescription = "(" whsp
numericoid whsp ; MatchingRule identifier
[ "NAME" qdescrs ]
[ "DESC" qdstring ]
[ "OBSOLETE" whsp ]
"SYNTAX" numericoid
whsp ")"The matchingRuleUse values are where you find the attributes that work with an extensible matching rule 🎀
MatchingRuleUseDescription = "(" whsp
numericoid whsp ; MatchingRule identifier
[ "NAME" qdescrs ]
[ "DESC" qdstring ]
[ "OBSOLETE" ]
"APPLIES" oids ; AttributeType identifiers
whsp ")"Servers that support matching rules and the extensibleMatch SHOULD implement all the matching rules in section 8. Big yes, bestie 🌸
Servers MAY implement extra matching rules that aren't listed in this document. If they do, they MUST publish the definitions of those matching rules in the matchingRules attribute of their subschema entries. And if the server supports the extensibleMatch, it MUST publish the relationship between the matching rules and attributes in the matchingRuleUse attribute. Main character energy for real 👑
Here's an example 🧚 Say a server has a privately-defined matching rule that does sound-alike matches on Directory String-valued attributes. It would put the following in the subschema entry. (1.2.3.4.5 is just a placeholder, and the OID of a real matching rule would look different.)
matchingRule: ( 1.2.3.4.5 NAME 'soundAlikeMatch'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.15 )If that matching rule could be used with the attributes 2.5.4.41 and 2.5.4.15, the subschema entry would also have this:
matchingRuleUse: ( 1.2.3.4.5 APPLIES (2.5.4.41 $ 2.5.4.15) )Then a client could actually use this rule by sending a search operation where the filter is the extensibleMatch choice, the matchingRule field is "soundAlikeMatch", and the type field is "2.5.4.41" or "2.5.4.15" 🦋✨
5. Attribute Types 🎀
All LDAP server implementations MUST recognize the attribute types defined in this section. Non-negotiable, bestie 💅
Servers SHOULD also recognize all the attributes from section 5 of [12] 🌈
5.1. Standard Operational Attributes 💖
Servers MUST maintain values of these attributes in accordance with the definitions in X.501(93). They have to keep these updated, no cap 🫶
5.1.1. createTimestamp ⏰
This attribute SHOULD appear in entries which were created using the Add operation.
( 2.5.18.1 NAME 'createTimestamp' EQUALITY generalizedTimeMatch
ORDERING generalizedTimeOrderingMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.24
SINGLE-VALUE NO-USER-MODIFICATION USAGE directoryOperation )5.1.2. modifyTimestamp ✏️
This attribute SHOULD appear in entries which have been modified using the Modify operation.
( 2.5.18.2 NAME 'modifyTimestamp' EQUALITY generalizedTimeMatch
ORDERING generalizedTimeOrderingMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.24
SINGLE-VALUE NO-USER-MODIFICATION USAGE directoryOperation )5.1.3. creatorsName 🧑🎨
This attribute SHOULD appear in entries which were created using the Add operation.
( 2.5.18.3 NAME 'creatorsName' EQUALITY distinguishedNameMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.12
SINGLE-VALUE NO-USER-MODIFICATION USAGE directoryOperation )5.1.4. modifiersName 🛠️
This attribute SHOULD appear in entries which have been modified using the Modify operation.
( 2.5.18.4 NAME 'modifiersName' EQUALITY distinguishedNameMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.12
SINGLE-VALUE NO-USER-MODIFICATION USAGE directoryOperation )5.1.5. subschemaSubentry 🗂️
The value of this attribute is the name of a subschema entry (or subentry if the server is based on X.500(93)). The server uses that entry to make the attributes that describe the schema available 💜
( 2.5.18.10 NAME 'subschemaSubentry'
EQUALITY distinguishedNameMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.12 NO-USER-MODIFICATION
SINGLE-VALUE USAGE directoryOperation )5.1.6. attributeTypes 📖
This attribute is typically located in the subschema entry.
( 2.5.21.5 NAME 'attributeTypes'
EQUALITY objectIdentifierFirstComponentMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.3 USAGE directoryOperation )5.1.7. objectClasses 🧩
This attribute is typically located in the subschema entry.
( 2.5.21.6 NAME 'objectClasses'
EQUALITY objectIdentifierFirstComponentMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.37 USAGE directoryOperation )5.1.8. matchingRules 🔍
This attribute is typically located in the subschema entry.
( 2.5.21.4 NAME 'matchingRules'
EQUALITY objectIdentifierFirstComponentMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.30 USAGE directoryOperation )5.1.9. matchingRuleUse 🎯
This attribute is typically located in the subschema entry.
( 2.5.21.8 NAME 'matchingRuleUse'
EQUALITY objectIdentifierFirstComponentMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.31 USAGE directoryOperation )5.2. LDAP Operational Attributes 🌟
These attributes are only present in the root DSE (see [1] and [3]). The root DSE is the main entry point, so these are the ones that matter most 👑
Servers MUST recognize these attribute names. But it is not required that a server provide values for these attributes when the attribute corresponds to a feature the server doesn't implement. That's a fair deal, periodt 💅
5.2.1. namingContexts 🗺️
The values of this attribute correspond to naming contexts that this server masters or shadows. If the server doesn't master any information (for example, it's an LDAP gateway to a public X.500 directory), this attribute will be absent. If the server believes it contains the entire directory, the attribute will have a single value, and that value will be the empty string (indicating the null DN of the root). This attribute lets a client pick suitable base objects for searching once it has contacted a server 🦋
( 1.3.6.1.4.1.1466.101.120.5 NAME 'namingContexts'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.12 USAGE dSAOperation )5.2.2. altServer 🆘
The values of this attribute are URLs of other servers that may be contacted when this server becomes unavailable. If the server doesn't know of any other servers that could be used, this attribute will be absent. Clients may cache this information in case their preferred LDAP server later becomes unavailable 🫶
( 1.3.6.1.4.1.1466.101.120.6 NAME 'altServer'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 USAGE dSAOperation )5.2.3. supportedExtension 🧰
The values of this attribute are OBJECT IDENTIFIERs that identify the supported extended operations the server supports.
If the server doesn't support any extensions, this attribute will be absent.
( 1.3.6.1.4.1.1466.101.120.7 NAME 'supportedExtension'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.38 USAGE dSAOperation )5.2.4. supportedControl 🎛️
The values of this attribute are the OBJECT IDENTIFIERs that identify controls the server supports. If the server doesn't support any controls, this attribute will be absent.
( 1.3.6.1.4.1.1466.101.120.13 NAME 'supportedControl'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.38 USAGE dSAOperation )5.2.5. supportedSASLMechanisms 🔐
The values of this attribute are the names of the supported SASL mechanisms the server supports. If the server doesn't support any mechanisms, this attribute will be absent.
( 1.3.6.1.4.1.1466.101.120.14 NAME 'supportedSASLMechanisms'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.15 USAGE dSAOperation )5.2.6. supportedLDAPVersion 📅
The values of this attribute are the versions of the LDAP protocol that the server implements.
( 1.3.6.1.4.1.1466.101.120.15 NAME 'supportedLDAPVersion'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.27 USAGE dSAOperation )5.3. LDAP Subschema Attribute 📚
This attribute is typically located in the subschema entry.
5.3.1. ldapSyntaxes 🧾
Servers MAY use this attribute to list the syntaxes they implement. Each value corresponds to one syntax 🌈
( 1.3.6.1.4.1.1466.101.120.16 NAME 'ldapSyntaxes'
EQUALITY objectIdentifierFirstComponentMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.54 USAGE directoryOperation )5.4. X.500 Subschema attributes 🏛️
These attributes are located in the subschema entry. All servers SHOULD recognize their name, although typically only X.500 servers will implement their functionality 🦋
5.4.1. dITStructureRules 🌳
( 2.5.21.1 NAME 'dITStructureRules' EQUALITY integerFirstComponentMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.17 USAGE directoryOperation )5.4.2. nameForms 📝
( 2.5.21.7 NAME 'nameForms'
EQUALITY objectIdentifierFirstComponentMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.35 USAGE directoryOperation )5.4.3. ditContentRules 📐
( 2.5.21.2 NAME 'dITContentRules'
EQUALITY objectIdentifierFirstComponentMatch
SYNTAX 1.3.6.1.4.1.1466.115.121.1.16 USAGE directoryOperation )6. Syntaxes 🌸
Servers SHOULD recognize all the syntaxes described in this section 💖
6.1. Attribute Type Description 📖
( 1.3.6.1.4.1.1466.115.121.1.3 DESC 'Attribute Type Description' )Values in this syntax are encoded according to the BNF given at the start of section 4.2. For example:
( 2.5.4.0 NAME 'objectClass'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.38 )6.2. Binary 🔢
( 1.3.6.1.4.1.1466.115.121.1.5 DESC 'Binary' )Values in this syntax are encoded as described in section 4.3.1 ✨
6.3. Bit String 🧲
( 1.3.6.1.4.1.1466.115.121.1.6 DESC 'Bit String' )Values in this syntax are encoded according to the following BNF:
bitstring = "'" *binary-digit "'B"
binary-digit = "0" / "1"Example:
'0101111101'B6.4. Boolean ✅
( 1.3.6.1.4.1.1466.115.121.1.7 DESC 'Boolean' )Values in this syntax are encoded according to the following BNF:
boolean = "TRUE" / "FALSE"Boolean values are encoded as "TRUE" if they're logically true, and as "FALSE" otherwise 🫶
6.5. Certificate 🎓
( 1.3.6.1.4.1.1466.115.121.1.8 DESC 'Certificate' )Because of the changes from X.509(1988) and X.509(1993), plus additional changes to the ASN.1 definition to support certificate extensions, no string representation is defined. Values in this syntax MUST only be transferred using the binary encoding, by requesting or returning the attributes with descriptions "userCertificate;binary" or "caCertificate;binary". The BNF notation in RFC 1778 for "User Certificate" is not recommended to be used 🙈
ngl this one is a whole vibe check. Certificate values can only travel in binary, no string version exists, so don't try to make one up 💀
6.6. Certificate List 📜
( 1.3.6.1.4.1.1466.115.121.1.9 DESC 'Certificate List' )Because of the incompatibility of the X.509(1988) and X.509(1993) definitions of revocation lists, values in this syntax MUST only be transferred using a binary encoding. You request or return them with the attributes described as "certificateRevocationList;binary" or "authorityRevocationList;binary". The BNF notation in RFC 1778 for "Authority Revocation List" is not recommended to be used 🌈
6.7. Certificate Pair 🎀
( 1.3.6.1.4.1.1466.115.121.1.10 DESC 'Certificate Pair' )okay so bestie, the certificate is carried in binary here, which means values in this syntax MUST only be transferred using a binary encoding 🔒. You request or return it by asking for the attribute description crossCertificatePair;binary. Also, the BNF notation in RFC 1778 for "Certificate Pair" is not recommended to be used 🙅♀️.
6.8. Country String 🌍
( 1.3.6.1.4.1.1466.115.121.1.11 DESC 'Country String' )a value here is encoded the same way as a Directory String value 💕. The lowkey important bit is that this syntax is limited to values of exactly two printable string characters, from the list in ISO 3166 [14].
CountryString = p pExample:
US6.9. DN 🧭
( 1.3.6.1.4.1.1466.115.121.1.12 DESC 'DN' )Values in the Distinguished Name syntax get the representation defined in [5] ✨. Heads up though, this representation can't be turned back into the ASN.1 encoding X.500 uses for Distinguished Names, because the CHOICE of any DirectoryString element in an RDN is no longer known 😵💫.
Examples (from [5]):
CN=Steve Kille,O=Isode Limited,C=GB
OU=Sales+CN=J. Smith,O=Widget Inc.,C=US
CN=L. Eagle,O=Sue\, Grabbit and Runn,C=GB
CN=Before\0DAfter,O=Test,C=GB
1.3.6.1.4.1.1466.0=#04024869,O=Test,C=GB
SN=Lu\C4\8Di\C4\876.10. Directory String 💬
( 1.3.6.1.4.1.1466.115.121.1.15 DESC 'Directory String' )A string in this syntax is encoded in the UTF-8 form of ISO 10646 (a superset of Unicode) 🌈. Servers and clients MUST be prepared to receive encodings of arbitrary Unicode characters, including characters not presently assigned to any character set 🫶.
For characters in the PrintableString form, the value is encoded as the string value itself.
If it is of the TeletexString form, then the characters are transliterated to their equivalents in UniversalString, and encoded in UTF-8 [9].
If it is of the UniversalString or BMPString forms [10], UTF-8 is used to encode them.
Note: the form of DirectoryString is not indicated in protocol unless the attribute value is carried in binary. Servers which convert to DAP MUST choose an appropriate form. Servers MUST NOT reject values merely because they contain legal Unicode characters outside of the range of printable ASCII. No rejecting the emoji, periodt 💅
Example:
This is a string of DirectoryString containing #!%#@6.11. DIT Content Rule Description 📋
( 1.3.6.1.4.1.1466.115.121.1.16 DESC 'DIT Content Rule Description' )Values in this syntax are encoded according to the following BNF. Implementors should note that future versions of this document may have expanded this BNF to include additional terms 👀.
DITContentRuleDescription = "("
numericoid ; Structural ObjectClass identifier
[ "NAME" qdescrs ]
[ "DESC" qdstring ]
[ "OBSOLETE" ]
[ "AUX" oids ] ; Auxiliary ObjectClasses
[ "MUST" oids ] ; AttributeType identifiers
[ "MAY" oids ] ; AttributeType identifiers
[ "NOT" oids ] ; AttributeType identifiers
")"6.12. Facsimile Telephone Number 📠
( 1.3.6.1.4.1.1466.115.121.1.22 DESC 'Facsimile Telephone Number' )Values in this syntax are encoded according to the following BNF:
fax-number = printablestring [ "$" faxparameters ]
faxparameters = faxparm / ( faxparm "$" faxparameters )
faxparm = "twoDimensional" / "fineResolution" /
"unlimitedLength" /
"b4Length" / "a3Width" / "b4Width" / "uncompressed"So in the above, the first printablestring is the telephone number, based on E.123 [15], and the faxparm tokens are the fax parameters 🧚.
6.13. Fax 🖨️
( 1.3.6.1.4.1.1466.115.121.1.23 DESC 'Fax' )Values in this syntax are encoded as if they were octet strings containing Group 3 Fax images as defined in [7].
6.14. Generalized Time ⏰
( 1.3.6.1.4.1.1466.115.121.1.24 DESC 'Generalized Time' )Values in this syntax are encoded as printable strings, represented as specified in X.208. The time zone must be specified. It is strongly recommended that GMT time be used 🕰️. For example:
199412161032Z6.15. IA5 String 🔤
( 1.3.6.1.4.1.1466.115.121.1.26 DESC 'IA5 String' )The encoding of a value in this syntax is the string value itself.
6.16. INTEGER 🔢
( 1.3.6.1.4.1.1466.115.121.1.27 DESC 'INTEGER' )Values in this syntax are encoded as the decimal representation of their values, with each decimal digit represented by its character equivalent. So the number 1321 is represented by the character string "1321" 💯.
6.17. JPEG 📸
( 1.3.6.1.4.1.1466.115.121.1.28 DESC 'JPEG' )Values in this syntax are encoded as strings containing JPEG images in the JPEG File Interchange Format (JFIF), as described in [8] ✨.
6.18. Matching Rule Description 🧩
( 1.3.6.1.4.1.1466.115.121.1.30 DESC 'Matching Rule Description' )Values of type matchingRules are encoded as strings according to the BNF given in section 4.5.
6.19. Matching Rule Use Description 🧩
( 1.3.6.1.4.1.1466.115.121.1.31 DESC 'Matching Rule Use Description' )Values of type matchingRuleUse are encoded as strings according to the BNF given in section 4.5.
6.20. MHS OR Address 📬
( 1.3.6.1.4.1.1466.115.121.1.33 DESC 'MHS OR Address' )Values in this syntax are encoded as strings, according to the format defined in [11].
6.21. Name And Optional UID 🆔
( 1.3.6.1.4.1.1466.115.121.1.34 DESC 'Name And Optional UID' )Values in this syntax are encoded according to the following BNF:
NameAndOptionalUID = DistinguishedName [ "#" bitstring ]Although the '#' character may occur in a string representation of a distinguished name, no additional special quoting is done. This syntax has been added subsequent to RFC 1778 🌸.
Example:
1.3.6.1.4.1.1466.0=#04024869,O=Test,C=GB#'0101'B6.22. Name Form Description 📝
( 1.3.6.1.4.1.1466.115.121.1.35 DESC 'Name Form Description' )Values in this syntax are encoded according to the following BNF. Implementors should note that future versions of this document may have expanded this BNF to include additional terms.
NameFormDescription = "(" whsp
numericoid whsp ; NameForm identifier
[ "NAME" qdescrs ]
[ "DESC" qdstring ]
[ "OBSOLETE" whsp ]
"OC" woid ; Structural ObjectClass
"MUST" oids ; AttributeTypes
[ "MAY" oids ] ; AttributeTypes
whsp ")"6.23. Numeric String 🔟
( 1.3.6.1.4.1.1466.115.121.1.36 DESC 'Numeric String' )The encoding of a string in this syntax is the string value itself.
Example:
19976.24. Object Class Description 🎭
( 1.3.6.1.4.1.1466.115.121.1.37 DESC 'Object Class Description' )Values in this syntax are encoded according to the BNF in section 4.4.
6.25. OID 🪪
( 1.3.6.1.4.1.1466.115.121.1.38 DESC 'OID' )Values in the Object Identifier syntax are encoded according to the BNF in section 4.1 for "oid".
Example:
1.2.3.4
cn6.26. Other Mailbox 📧
( 1.3.6.1.4.1.1466.115.121.1.39 DESC 'Other Mailbox' )Values in this syntax are encoded according to the following BNF:
otherMailbox = mailbox-type "$" mailbox
mailbox-type = printablestring
mailbox = <an encoded IA5 String>In the above, mailbox-type is the type of mail system the mailbox lives in, for example "MCIMail" 📮. The mailbox is the actual mailbox in the mail system defined by mailbox-type.
6.27. Postal Address 🏡
( 1.3.6.1.4.1.1466.115.121.1.41 DESC 'Postal Address' )Values in this syntax are encoded according to the following BNF:
postal-address = dstring *( "$" dstring )In the above, each dstring component of a postal address value is encoded as a value of type Directory String syntax. Backslashes and dollar characters, if they occur in the component, are quoted as described in section 4.3. Many servers limit the postal address to six lines of up to thirty characters 📏.
Example:
1234 Main St.$Anytown, CA 12345$USA
\241,000,000 Sweepstakes$PO Box 1000000$Anytown, CA 12345$USA6.28. Presentation Address 🗺️
( 1.3.6.1.4.1.1466.115.121.1.43 DESC 'Presentation Address' )Values in this syntax are encoded with the representation described in RFC 1278 [6].
6.29. Printable String 🖊️
( 1.3.6.1.4.1.1466.115.121.1.44 DESC 'Printable String' )The encoding of a value in this syntax is the string value itself. PrintableString is limited to the characters in production p of section 4.1.
Example:
This is a PrintableString6.30. Telephone Number 📞
( 1.3.6.1.4.1.1466.115.121.1.50 DESC 'Telephone Number' )Values in this syntax are encoded as if they were Printable String types. Telephone numbers are recommended in X.520 to be in international form, as described in E.123 [15] 🌍.
Example:
+1 512 305 02806.31. UTC Time 🕓
( 1.3.6.1.4.1.1466.115.121.1.53 DESC 'UTC Time' )Values in this syntax are encoded as if they were printable strings with the strings containing a UTCTime value. This is historical; new attribute definitions SHOULD use GeneralizedTime instead 🕰️. Bestie, it's giving vintage, but Generalized Time is the one to pick for new stuff ✨.
6.32. LDAP Syntax Description 📖
( 1.3.6.1.4.1.1466.115.121.1.54 DESC 'LDAP Syntax Description' )Values in this syntax are encoded according to the BNF in section 4.3.3.
6.33. DIT Structure Rule Description 🌳
( 1.3.6.1.4.1.1466.115.121.1.17 DESC 'DIT Structure Rule Description' )Values with this syntax are encoded according to the following BNF:
DITStructureRuleDescription = "(" whsp
ruleidentifier whsp ; DITStructureRule identifier
[ "NAME" qdescrs ]
[ "DESC" qdstring ]
[ "OBSOLETE" whsp ]
"FORM" woid whsp ; NameForm
[ "SUP" ruleidentifiers whsp ] ; superior DITStructureRules
")"
ruleidentifier = integer
ruleidentifiers = ruleidentifier |
"(" whsp ruleidentifierlist whsp ")"
ruleidentifierlist = [ ruleidentifier *( ruleidentifier ) ]7. Object Classes 🧸
Servers SHOULD recognize all the names of standard classes from section 7 of [12] 👑.
7.1. Extensible Object Class 🌈
The extensibleObject object class, if present in an entry, permits that entry to optionally hold any attribute. The MAY attribute list of this class is implicitly the set of all attributes 🫧.
( 1.3.6.1.4.1.1466.101.120.111 NAME 'extensibleObject'
SUP top AUXILIARY )The mandatory attributes of the other object classes of this entry are still required to be present.
Note that not all servers will implement this object class, and those which do not will reject requests to add entries which contain this object class, or modify an entry to add this object class. So check first, bestie 🙈.
7.2. subschema 🗂️
This object class is used in the subschema entry.
( 2.5.20.1 NAME 'subschema' AUXILIARY
MAY ( dITStructureRules $ nameForms $ ditContentRules $
objectClasses $ attributeTypes $ matchingRules $
matchingRuleUse ) )The ldapSyntaxes operational attribute may also be present in subschema entries 💜.
8. Matching Rules 🔍
Servers which implement the extensibleMatch filter SHOULD allow all the matching rules listed in this section to be used in the extensibleMatch. In general these servers SHOULD allow matching rules to be used with all attribute types known to the server, when the assertion syntax of the matching rule is the same as the value syntax of the attribute 🥰.
Servers MAY implement additional matching rules 🌸.
8.1. Matching Rules used in Equality Filters ✨
Okay bestie, this is the matching rules menu 🍓 Servers SHOULD be able to do all of these. For every single one, the assertion syntax is the same as the value syntax, so what you type in the filter looks just like what's stored. Love that for us 💅
( 2.5.13.0 NAME 'objectIdentifierMatch'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.38 )
If the client supplies a filter using an objectIdentifierMatch whose
matchValue oid is in the "descr" form, and the oid is not recognized
by the server, then the filter is Undefined.
( 2.5.13.1 NAME 'distinguishedNameMatch'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.12 )
( 2.5.13.2 NAME 'caseIgnoreMatch'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.15 )
( 2.5.13.8 NAME 'numericStringMatch'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.36 )
( 2.5.13.11 NAME 'caseIgnoreListMatch'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.41 )
( 2.5.13.14 NAME 'integerMatch'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.27 )
( 2.5.13.16 NAME 'bitStringMatch'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.6 )
( 2.5.13.20 NAME 'telephoneNumberMatch'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.50 )
( 2.5.13.22 NAME 'presentationAddressMatch'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.43 )
( 2.5.13.23 NAME 'uniqueMemberMatch'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.34 )
( 2.5.13.24 NAME 'protocolInformationMatch'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.42 )
( 2.5.13.27 NAME 'generalizedTimeMatch'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.24 )
( 1.3.6.1.4.1.1466.109.114.1 NAME 'caseExactIA5Match'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 )
( 1.3.6.1.4.1.1466.109.114.2 NAME 'caseIgnoreIA5Match'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 )When you're doing caseIgnoreMatch, caseIgnoreListMatch, telephoneNumberMatch, caseExactIA5Match or caseIgnoreIA5Match, multiple adjoining whitespace characters are treated the same as one single space, and any leading or trailing whitespace just gets ignored. Spacing drama, resolved 🫶
Clients MUST NOT assume that servers can transliterate Unicode values. Do not count on your server to do that translation for you, bestie 🚫
8.2. Matching Rules used in Inequality Filters 🦋
Servers SHOULD be able to do these matching rules too, the ones used in greaterOrEqual and lessOrEqual filters. Ordering era 📏
( 2.5.13.28 NAME 'generalizedTimeOrderingMatch'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.24 )
( 2.5.13.3 NAME 'caseIgnoreOrderingMatch'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.15 )The sort ordering for a caseIgnoreOrderingMatch is implementation-dependent, so it's up to whoever built the implementation. No cap, that's a vibe check 🤷♀️
8.3. Syntax and Matching Rules used in Substring Filters 🌸
Okay so the Substring Assertion syntax is only used as the syntax of assertion values in the extensible match. It is NOT the syntax of attributes, and it is NOT used in the substring filter itself. Know your lane, Substring Assertion 💜
( 1.3.6.1.4.1.1466.115.121.1.58 DESC 'Substring Assertion' )The Substring Assertion gets encoded according to this BNF, and it's giving very structured:
substring = [initial] any [final]
initial = value
any = "*" *(value "*")
final = valueThe <value> production is a UTF-8 encoded string. Should the backslash or asterix characters show up in a production of <value>, they are quoted as described in section 4.3. Escape those, friend 🙈
Servers SHOULD be able to do these matching rules, which are used in substring filters:
( 2.5.13.4 NAME 'caseIgnoreSubstringsMatch'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.58 )
( 2.5.13.21 NAME 'telephoneNumberSubstringsMatch'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.58 )
( 2.5.13.10 NAME 'numericStringSubstringsMatch'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.58 )8.4. Matching Rules for Subschema Attributes 🧚
Now this one is serious, so listen up 👑 Servers which let clients modify subschema entries MUST support the following matching rules, because they're the equality matching rules for several of the subschema attributes. Non-negotiable, periodt 💅
( 2.5.13.29 NAME 'integerFirstComponentMatch'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.27 )
( 2.5.13.30 NAME 'objectIdentifierFirstComponentMatch'
SYNTAX 1.3.6.1.4.1.1466.115.121.1.38 )Implementors should note that the assertion syntax of these matching rules, an INTEGER or OID, is different from the value syntax of the attributes they're the equality matching rule for. Plot twist alert 🚨
If the client supplies an extensible filter using an objectIdentifierFirstComponentMatch whose matchValue is in the "descr" form, and the OID is not recognized by the server, then the filter is Undefined. Undefined, bestie 🫠
9. Security Considerations 🔐
This part is dramatic, and honestly it deserves to be. Please read it fully ✨
9.1. Disclosure 👀
Attributes of directory entries are used to give descriptive information about the real-world objects they represent, and those can be people, organizations or devices. Most countries have privacy laws about publishing information about people, so be careful with who gets to see what 🙈
9.2. Use of Attribute Values in Security Applications 🪪
The transformations of an AttributeValue value from its X.501 form into an LDAP string representation are not always reversible back to the same BER or DER form. An example of a situation that needs the DER form of a distinguished name is verifying an X.509 certificate. Big stakes, no cap 😭
For example, a distinguished name with one RDN and one AVA, where the type is commonName and the value is of the TeletexString choice with the letters 'Sam', would be represented in LDAP as the string CN=Sam. Another distinguished name where the value is still 'Sam' but of the PrintableString choice would have the exact same representation, CN=Sam. Same string, different underlying thing. Iconic chaos 💀
Applications which need to rebuild the DER form of the value SHOULD NOT use the string representation of attribute syntaxes when converting a value to LDAP format. Instead, they SHOULD use the Binary syntax. Don't take the shortcut, use Binary 🚫🧾
10. Acknowledgements 🫶
This document is based substantially on RFC 1778, written by Tim Howes, Steve Kille, Wengyik Yeong and Colin Robbins. Shoutout to them for the foundation 🌈
Many of the attribute syntax encodings defined in this and related documents are adapted from those used in the QUIPU and the IC R3 X.500 implementations. The contributions of the authors of both of these implementations to the specification of syntaxes are gratefully acknowledged. Thank you, legends 👑
11. Authors' Addresses 💌
Mark Wahl
Critical Angle Inc.
4815 West Braker Lane #502-385
Austin, TX 78759
USA
Phone: +1 512 372-3160
EMail: M.Wahl@critical-angle.com
Andy Coulbeck
Isode Inc.
9390 Research Blvd Suite 305
Austin, TX 78759
USA
Phone: +1 512 231-8993
EMail: A.Coulbeck@isode.com
Tim Howes
Netscape Communications Corp.
501 E. Middlefield Rd, MS MV068
Mountain View, CA 94043
USA
Phone: +1 650 937-3419
EMail: howes@netscape.com
Steve Kille
Isode Limited
The Dome, The Square
Richmond
TW9 1DT
UK
Phone: +44-181-332-9091
EMail: S.Kille@isode.com12. Bibliography 📚
- [1] Wahl, M., Howes, T., and S. Kille, "Lightweight Directory Access Protocol (v3)", RFC 2251, December 1997.
- [2] The Directory: Selected Attribute Types. ITU-T Recommendation X.520, 1993.
- [3] The Directory: Models. ITU-T Recommendation X.501, 1993.
- [4] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119, March 1997.
- [5] Wahl, M., Kille, S., and T. Howes, "Lightweight Directory Access Protocol (v3): UTF-8 String Representation of Distinguished Names", RFC 2253, December 1997.
- [6] Kille, S., "A String Representation for Presentation Addresses", RFC 1278, November 1991.
- [7] Terminal Equipment and Protocols for Telematic Services - Standardization of Group 3 facsimile apparatus for document transmission. CCITT, Recommendation T.4.
- [8] JPEG File Interchange Format (Version 1.02). Eric Hamilton, C-Cube Microsystems, Milpitas, CA, September 1, 1992.
- [9] Yergeau, F., "UTF-8, a transformation format of Unicode and ISO 10646", RFC 2044, October 1996.
- [10] Universal Multiple-Octet Coded Character Set (UCS) - Architecture and Basic Multilingual Plane, ISO/IEC 10646-1 : 1993 (With amendments).
- [11] Hardcastle-Kille, S., "Mapping between X.400(1988) / ISO 10021 and RFC 822", RFC 1327, May 1992.
- [12] Wahl, M., "A Summary of the X.500(96) User Schema for use with LDAPv3", RFC 2256, December 1997.
- [13] Crocker, D., "Standard of the Format of ARPA-Internet Text Messages", STD 11, RFC 822, August 1982.
- [14] ISO 3166, "Codes for the representation of names of countries".
- [15] ITU-T Rec. E.123, Notation for national and international telephone numbers, 1988.
13. Full Copyright Statement ⚖️
Copyright (C) The Internet Society (1997). All Rights Reserved. Mine, legally 💜
This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards, in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English.
The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 🌸
📦 where this page comes from
- ietf: rfc2252 1997-12
- 💖 girlified by claude-haiku-5-5 on : a language model's rewrite of the original, under its terms