RFC2377 - Naming Plan for Internet Directory-Enabled Applications

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　　Network Working Group A. Grimstad
Request for Comments: 2377 R. Huber
Category: Informational AT&T
S. Sataluri
Lucent Technologies
M. Wahl
Critical Angle Inc.
September 1998

Naming Plan for Internet Directory-Enabled Applications

Status of this Memo

This memo provides information for the Internet community. It does
not specify an Internet standard of any kind. Distribution of this
memo is unlimited.

Copyright Notice

Copyright (C) The Internet Society (1998). All Rights Reserved.

Abstract

Application of the conventional X.500 approach to naming has
heretofore, in the experience of the authors, proven to be an
obstacle to the wide deployment of directory-enabled applications on
the Internet. We propose a new directory naming plan that leverages
the strengths of the most popular and successful Internet naming
schemes for naming objects in a hierarchical directory. This plan
can, we believe, by extending the X.500 approach to naming,
facilitate the creation of an Internet White Pages Service (IWPS) and
other directory-enabled applications by overcoming the problems
encountered by those using the conventional X.500 approach.

1.0 Executive Summary

Application of the conventional X.500 approach to naming has
heretofore, in the experience of the authors, proven to be an
obstacle to the wide deployment of directory-enabled applications on
the Internet. The required registration infrastructure is either
non-existent or largely ignored. The infrastructure that does exist
is cumbersome to use and tends to produce counterproductive results.
The attributes used for naming have been confusing for users and
inflexible to managers and operators of directory servers.

This paper describes a directory naming plan for the construction of
an Internet directory infrastructure to support directory-enabled
applications that can serve as an alternative (or extension) to the
conventional X.500 approach.

The plan has the following two main features. First, it bases the
root and upper portions of the name hierarchy on the existing
infrastructure of names from the Domain Name System (DNS). This
component of the plan makes use of the ideas described in the
companion paper to this plan, "Using Domains in LDAP Distinguished
Names" [1]. And second, it provides a number of options for the
assignment of names to directory leaf objects such as person objects,
including an option that allows the reuse of existing Internet
identifiers for people.

Just as the conventional X.500 style of naming is not a formal
standard, use of the naming plan described here is not obligatory for
directory-enabled applications on the Internet. Other approaches are
permissible. However, we believe widespread use of this plan will
largely eliminate naming as a typically thorny issue when
administrators set up an LDAP-based directory service. Further, we
strongly encourage developers of directory-enabled products,
especially LDAP clients and user interfaces, to assume that this
naming plan will see widespread use and design their products
accordingly.

Here, in summary, is our proposal.

The upper portions of the hierarchical directory tree should be
constructed using the components of registered DNS names using the
domain component attribute "dc". The directory name for the
organization having the domain name "acme.com" will then be, e.g.,

dc=acme, dc=com

Organizations can add additional directory structure, for example to
support implementation of access control lists or partitioning of
their directory information, by using registered subdomains of DNS
names, e.g., the subdomain "corporate.acme.com" can be used as the
basis for the directory name

dc=corporate, dc=acme, dc=com

For naming directory leaf objects such as persons, groups, server
applications and certification authorities in a hierarchical
directory, we propose the use of either the "uid" (user identifier)
or the "cn" (common name) attribute for the relative distinguished
name. This plan does not constrain how these two attributes are used.

One approach to their use, for example, is to employ the uid
attribute as the RDN when reusing an existing store of identifiers
and the cn attribute as the RDN when creating new identifiers
specifically for the directory. A convenient existing identification
scheme for person objects is the RFC822 mailbox identifier. So an RDN
for person employing this store of identifiers would be, e.g.,

uid=John.Smith@acme.com

For leaf objects not conveniently identified with such a scheme, the
"cn" attribute is used, e.g.,

cn=Reading Room

Directory distinguished names will thus have the following structure,
e.g.,

uid=John.Smith@acme.com, dc=acme, dc=com
uid=Mary.Jones@acme.com, dc=corporate, dc=acme, dc=com
uid=J.Smith@worldnet.att.net, dc=legal, dc=acme, dc=com
cn=Reading Room, dc=physics, dc=national-lab, dc=edu

2.0 The Problem

The X.500 Directory model [2] can be used to create a world-wide
distributed directory. The Internet X.500 Directory Pilot has been
operational for several years and has grown to a size of about 1.5
million entries of varying quality. The rate of growth of the pilot
is far lower than the rate of growth of the Internet during the pilot
period.

There are a substantial number of contributing factors that have
inhibited the growth of this pilot. The common X.500 approach to
naming, while not the preponderant problem, has contributed in
several ways to limit the growth of an Internet White Pages Service
based on X.500.

The conventional way to construct names in the X.500 community is
documented as an informative (i.e., not officially standardized)
Annex B to X.521. The relative distinguished name (RDN) of a user
consists of a common name (cn) attribute. This is meant to be what --
in the user's particular society -- is customarily understood to be
the name of that user. The distinguished name of a user is the
combination of the name of some general object, such as an
organization or a geographical unit, with the common name. There are
two main problems with this style of name construction.

First, the common name attribute, while seeming to be user-friendly,
cannot be used generally as an RDN in practice. In any significant
set of users to be named under the same Directory Information Tree
(DIT) node there will be collisions on common name. There is no way
to overcome this other than either by forcing uniqueness on common
names, something they do not possess, or by using an additional
attribute to prevent collisions. This additional attribute normally
needs to be unique in a much larger context to have any practical
value. The end result is a RDN that is very long and unpopular with
users.

Second, and more serious, X.500 has not been able to use any
significant number of pre-existing names. Since X.500 naming models
typically use organization names as part of the hierarchy [2, 3],
organization names must be registered. As organization names are
frequently tied to trademarks and are used in sales and promotions,
registration can be a difficult and acrimonious process.

The North American Directory Forum (NADF, now the North Atlantic
Directory Forum but still the NADF) proposed to avoid the problem of
registration by using names that were already registered in the
"civil naming infrastructure" [4][5]. Directory distinguished names
would be based on an organization's legal name as recognized by some
governmental agency (county clerk, state secretary of state, etc.) or
other registering entity such as ANSI.

This scheme has the significant advantage of keeping directory
service providers out of disputes about the right to use a particular
name, but it leads to rather obscure names. Among these obscurities,
the legal name almost invariably takes a form that is less familiar
and longer than what users typically associate with the organization.
For example, in the US a large proportion of legal organization names
end with the text ", Inc." as in "Acme, Inc." Moreover, in the case
of the US, the civil naming infrastructure does not operate
nationally, so the organization names it provides must be located
under state and regional DIT nodes, making them difficult to find
while browsing the directory. NADF proposes a way to algorithmically
derive multi-attribute RDNs which would allow placement of entries or
aliases in more convenient places in the DIT, but these derived names
are cumbersome and unpopular. For example, suppose Nadir is an
organization that is registered in New Jersey civil naming
infrastructure under the name "Nadir Networks, Inc." Its civil
distinguished name (DN) would then be

o="Nadir Networks, Inc.", st=New Jersey, c=US

while its derived name which is unambiguous under c=US directly is

o="Nadir Networks, Inc." + st=New Jersey, c=US

More generally, the requirement for registration of organizations in
X.500 naming has led to the establishment of national registration
authorities whose function is mainly limited to assignment of X.500
organization names. Because of the very limited attraction of X.500,
interest in registering an organization with one of these national
authorities has been minimal. Finally, multi-national organizations
are frustrated by a lack of an international registration authority.

3.0 Requirements

A directory naming plan must provide a guide for the construction of
names (identifiers, labels) for directory objects that are
unambiguous (identify only one directory object) within some context
(namespace), at a minimum within one isolated directory server.

A directory object is simply a set of attribute values. The
association between a real-world object and a directory object is
made by directory-enabled applications and is, in the general case,
one to many.

The following additional naming characteristics are requirements that
this naming plan seeks to satisfy:

a) hierarchical

The Internet, consisting of a very large number of objects and
management domains, requires hierarchical names. Such names permit
delegation in the name assignment process and partitioning of
directory information among directory servers.

b) friendly to loose coupling of directory servers

One purpose of this naming plan is to define a naming pattern that
will facilitate one form or another of loose coupling of potentially
autonomous directory servers into a larger system.

A name in such a loosely-coupled system should unambiguously identify
one real-world object. The real-world object may, however, be
represented differently (i.e. by different directory objects having
different attributes but the same DN) in different (e.g.
independently managed) servers in the loosely-coupled system. The
plan does not attempt to produce names to overcome this likely
scenario. That is, it does not attempt to produce a single namespace
for all directory objects. (This issue is considered in more detail

in Section 5.1.)

c) readily usable by LDAP clients and servers

As of this writing, a substantial number of the Lightweight Directory
Access Protocol (LDAP) [6][7] implementations are currently available
or soon will be. The names specified by this naming plan should be
readily usable by these implementations and applications based on
them.

d) friendly to re-use of existing Internet name registries

As described in Section 2 above, creation of new global name
registries has been highly problematic. Therefore, a fundamental
requirement this plan addresses is to enable the reuse of existing
Internet name registries such as DNS names and RFC822 mailbox
identifiers when constructing directory names.

e) minimally user-friendly

Although we expect that user interfaces of directory-enabled
applications will avoid exposing users to DNs, it is unlikely that
users can be totally insulated from them. For this reason, the
naming plan should permit use of familiar information in name
construction. Minimally, a user should be capable of recognizing the
information encoded in his/her own DN. Names that are totally opaque
to users cannot meet this requirement.

4.0 Name Construction

The paper assumes familiarity with the terminology and concepts
behind the terms distinguished name (DN) and relative distinguished
name (RDN) [2][8][9].

We describe how DNs can be constructed using three attribute types,
domainComponent (dc), userID (uid) and commonName (cn). They are
each described in turn.

4.1 Domain Component (dc)

The domain component attribute is defined and registered in RFC1274
[3][10]. It is used in the construction of a DN from a domain name.
Details of the construction algorithm is described in "Using Domains
in LDAP Distinguished Names" [1].

An organization wishing to deploy a directory following this naming
plan would proceed as follows. Consider an organization, for example
"Acme, Inc.", having the registered domain name "acme.com". It would

construct the DN

dc=acme, dc=com

from its domain name. It would then use this DN as the root of its
subtree of directory information.

The DN itself can be used to identify a directory organization object
that represents information about the organization. The directory
schema required to enable this is described below in section 5.2.

The subordinates of the DN will be directory objects related to the
organization. The domain component attribute can be used to name
subdivisions of the organization such as organizational units and
localities. Acme, for example, might use the domain names
"corporate.acme.com" and "richmond.acme.com" to construct the names

dc=corporate, dc=acme, dc=com
dc=richmond, dc=acme, dc=com

under which to place its directory objects. The directory schema
required to name organizationalUnit and locality objects in this way
is described below in section 5.2.

Note that subdivisions of the organization such as organizational
units and localities could also be assigned RDNs using the
conventional X.500 naming attributes, e.g.

ou=corporate, dc=acme, dc=com
l=richmond, dc=acme, dc=com.

Use of the dc attribute for the RDN of directory objects of class
"domain" is also possible [1].

4.2 User ID (uid)

The userid (uid) attribute is defined and registered in RFC1274
[3][10].

This attribute may be used to construct the RDN for directory objects
subordinate to objects named according to the procedure described in
Section 4.1. This plan does not constrain how this attribute is
used.

4.3 Common Name (cn)

The commonName (cn) attribute is defined and registered in X.500
[3][11].

This attribute may be used to construct the RDN for directory objects
subordinate to objects named according to the procedure described in
Section 4.1. This plan does not constrain how this attribute is
used.

4.4 Examples of uid and cn Usage

Although this plan places no constraints on the use of the uid and cn
attributes for name construction, we would like to offer some
suggestions by way of examples.

In practice, we have used uid for the RDN for person objects were we
could make use of an existing registry of names and cn for other
objects.

Examples of existing registries of identifiers for person objects are
RFC822 mailbox identifiers, employee numbers and employee "handles".
Aside from the convenience to administrators of re-use of an existing
store of identifiers, if it is ever necessary to display to a user
his/her DN, there is some hope that it will be recognizable when such
identifiers are used.

We have found RFC822 mailbox identifiers a particularly convenient
source for name construction. When a person has several e-mail
addresses, one will be selected for the purpose of user
identification. We call this the "distinguished" e-mail address or
the "distinguished" RFC822 mailbox identifier for the user.

For example, if there is a user affiliated with the organization Acme
having distinguished e-mail address J.Smith@acme.com, the uid
attribute will be:

uid=J.Smith@acme.com

The domain component attributes of a user's DN will normally be
constructed from the domain name of his/her distinguished e-mail
address. That is, for the user uid=J.Smith@acme.com the domain
component attributes would typically be:

dc=acme, dc=com

The full LDAP DN for this user would then be:

uid=J.Smith@acme.com, dc=acme, dc=com

Directory administrators having several RFC822 identifiers to choose
from when constructing a DN for a user should consider the following
factors:

o Machine-independent addresses are likely to be more stable,
resulting in directory names that change less. Thus an
identifier such as:

js@acme.com

may well be preferable to one such as:

js@blaster.third-floor.acme.com.

o Use of some form of "handle" for the "local" part that is
distinct from a user's real name may result in fewer collisions
and thereby lessen user pain and suffering. Thus the
identifier:

js@acme.com

may well be preferable to one such as:

J.Smith@acme.com

Practical experience with use of the RFC822 mailbox identifier scheme
described here has shown that there are situations where it is
convenient to use such identifies for all users in a particular
population, although a few users do not, in fact, possess working
mailboxes. For example, an organization may have a existing unique
identification scheme for all employees that is used as a alias to
the employees' real mailboxes -- which may be quite heterogeneous in
structure. The identification scheme works for all employees to
identify unambiguously each employee; it only works as an e-mail
alias for those employees having real mailboxes. For this reason it
would be a bad assumption for directory-enabled applications to
assume the uid to be a valid mailbox; the value(s) of the mail
attribute should always be checked.

It is important to emphasize that the elements of the domain name of
an RFC822 identifier may, BUT NEED NOT, be the same as the domain
components of the DN. This means that the domain components provide
a degree of freedom to support access control or other directory
structuring requirements that need not be mechanically reflected in
the user's e-mail address. We do not want under any condition to
force the user's e-mail address to change just to facilitate a new
system requirement such as a modification in an access control
structure. It should also be noted that while we do not require that
the domain components match the RFC822 identifier, we DO require that
the concatenated domain components form a registered domain name,
that is, one that is represented in the DNS. This automatically
avoids name conflicts in the directory hierarchy.

To provide an example of a DN which deviates from what might be
considered the default structure, consider the following scenario.

Suppose that J.Smith needs to be granted special permissions to
information in the dc=acme, dc=com part of the LDAP DIT. Since it
will be, in general, easier to organize special users by their name
structure than via groups (an arbitrary collection of DNs), we use
subdomains for this purpose. Suppose the special permissions were
required by users in the MIS organizational unit. A subdomain
"mis.acme.com" is established, if it does not already exist,
according to normal DNS procedures. The special permissions will be
granted to users with the name structure:

uid=*, dc=mis, dc=acme, dc=com

The DN of J.Smith in this case will be:

uid=J.Smith@acme.com, dc=mis, dc=acme, dc=com

In principal, there is nothing to prevent the domain name elements of
the RFC822 identifier from being completely different from the domain
components of the DN. For instance, the DN for a J.Smith could be:

uid=J.Smith@worldnet.att.net, dc=mis, dc=acme, dc=com

While we do not REQUIRE that the domain name part of the uid match
the dc components of the directory distinguished name, we suggest
that this be done where possible. At a minimum, if the most
significant pieces of the DN and the uid are the same (i.e.,
"dc=acme, dc=com" and "acme.com") the likelihood, based on a
knowledge of a user's e-mail address, of discovering an appropriate
directory system to contact to find information about the user is
greatly enhanced.

The example above represents a situation where this suggestion isn't
possible because some of the users in a population have mailbox
identifiers that differ from the pattern of the rest of the users,
e.g., most mailboxes are of the form local@acme.com, but a
subpopulation have mailboxes from an ISP and therefore mailboxes of
the form local@worldnet.att.net.

5.0 Naming Plan and Directories

5.1 Directory Services Considerations

We envision the deployment of LDAP-based directory services on the
Internet to take the form of loosely coupled LDAP servers. This
coupling will occur at two levels.

Firstly, LDAP servers will be loosely connected into islands (i.e. a
set of servers sharing a single DN namespace). The glue connecting
the islands will be LDAP referral [12] information configured into
the LDAP servers. An LDAP search directed to any server in such an
island can be answered, if the information is not available to that
server, by an LDAP referral to another, more appropriate server
within the same island.

Secondly, various techniques will be used span LDAP islands. The
concept that enables such techniques is the LDAP URL [13]. By
combining a DNS host name and port (corresponding to one or more LDAP
servers) with a DN, the LDAP URL provides unified high-level
identification scheme (an LDAP URL namespace) for directory objects.

Because an LDAP referral is expressed as one or more LDAP URL, these
two levels of coupling may not sharply distinguished in practice.

We do not envision the X.500 model of a single DIT (i.e. a single DN
namespace) to be viable in an environment of competing service
providers. This naming plan does not attempt to produce DNs to hide
the possibility that a given real-world object may have independently
managed directory objects with the same DN associated with it.

5.2 Directory Schema Implications of the Naming Plan

The traditional directory schema(s) developed for the X.500 standard
and its application to the Internet [4] require extension to be used
with the naming plan developed here. The extensions described below
attempt to reuse existing schema elements as much as possible. The
directory objects for which extensions are required are:
organization, organizational unit, and various classes of leaf
objects. We describe the schema modifications below for organization,
organizationalUnit and selected leaf classes.

So as to continue to use existing structural object classes to the
extent possible, we propose supplementing entries based on these
classes with additional information from two new auxiliary object
classes, dcObject and uidObject. They are specified using the
notation in Section 4 of [14].

The auxiliary object class dcObject is defined in "Using Domains in
LDAP Distinguished Names" [1].

The auxiliary object class uidObject is defined as:

( 1.3.6.1.1.3.1
NAME uidObject
SUP top
AUXILIARY
MUST uid )

5.2.1 Organization Schema

The dc attribute is employed to construct the RDN of an organization
object. This is enabled by adding the auxiliary class dcObject to
the organization's objectClass attribute.

5.2.2 Organizational Unit Schema

The dc attribute is employed to construct the RDN of an
organizationalUnit object (which is subordinate in the DIT to either
an organization or an organizationalUnit object). This is enabled by
adding the auxiliary class dcObject to the organizational unit's
objectClass attribute.

5.2.3 Person Schema

No schema extensions are required for person objects if either the
inetOrgPerson [15] (preferred) or the newPilotPerson object classes
are used. The attribute uid is permissible in each class. For
consistency, the uidObject could be added to person entry objectClass
attributes to assist applications filtering on this object class
attribute value. Use of other classes for person objects with RDN
constructed with the uid attribute such as organizationalPerson
requires the use of the uidObject class.

It has been traditional in X.500 and LDAP directory services to
employ the common name (cn) attribute in naming. While this naming
plan doesn't require use of the cn attribute in naming, it should be
stressed that it is a required attribute in any class derived from
the person class and is still quite important. It will play a
significant role in enabling searches to find user entries of
interest.

5.2.4 Certification Authority Schema

The certification authority (CA) object class is an auxiliary class,
meaning it is essentially a set of additional attributes for a base
class such as organizationalRole, organization, organizationalUnit or
person. Except in the case where the base structural class is
inetOrgPerson, use of the uid attribute to construct the RDN of a CA

will require the auxiliary class uidObject to permit the uid
attribute to be used. In the cases where organizationalUnit or
organization is the base class for a CA, use of the auxiliary class
dcObject will permit the RDN of the CA to be a domain component.

5.2.5 Server and Server Application Schema

Servers and server applications are typically represented, for want
of anything better, by entries of the object class applicationProcess
(or a class derived from it). Sometimes the class applicationEntity
is used. In either case, the uid attribute should probably not be
employed to construct the RDN of a server or server application
object. The standard schema uses the attribute cn for such RDNs.

Suppose one wants to use this naming plan both in the construction of
DNs for SSL server certificates and for their storage in a directory.
It is customary for clients connecting via SSL to compare the
server's domain name (e.g. from the URL used to contact the server)
with the value of the cn attribute in the subject field (i.e.
subject's DN) of the server's certificate. For this reason, it is
common practice to set the cn attribute to the server's domain name.

The naming and schema to handle this situation is best explained by
an example. Consider the server "host.acme.com". Following the
algorithm in "Using Domains in LDAP Distinguished Names" [1], the DN
dc=host, dc=acme, dc=com is constructed. To conform to the existing
practices just described, the server's subject DN for the SSL server
certificate should be cn=host.acme.com, dc=host, dc=acme, dc=com and
the server's certificate should be stored in a directory entry with
this name. This entry should use application process or application
entity as its structural object class and strong authentication user
as is auxiliary class.

5.2.6 Name Forms

For X.500 servers or LDAP servers following the X.500 model, our
schema requires the definition of new name forms, structure rules,
and DIT content rules. Structure rules and DIT content rules are
locally defined, and do not involve a globally significant object
identifier.

The following name forms are defined using the syntax of section 6.22
of [14] for the convenience of those using such servers.

Note that since the structural object classes organization,
organizationalUnit, locality and organizationalPerson do not permit
inclusion of the dc attribute, an auxiliary object class such as
dcObject [1] must be used for instances of these classes.)

5.2.6.1 Name Form for Domain Objects

The OIDs in this group are under the
iso.org.dod.internet.directory.NameForm branch of the OID tree
(1.3.6.1.1.2).

( 1.3.6.1.1.2.1
NAME domainNameForm
OC domain
MUST dc )

The domainNameForm name form indicates that objects of structural
object class domain have their RDN constructed from a value of the
attribute dc.

5.2.6.2 Name Form for Organization Objects

( 1.3.6.1.1.2.2
NAME dcOrganizationNameForm
OC organization
MUST dc )

The dcOrganizationNameForm name form indicates that objects of
structural object class organization have their RDN constructed from
a value of the attribute dc.

5.2.6.3 Name Form for Organizational Unit Objects

( 1.3.6.1.1.2.3
NAME dcOrganizationalUnitNameForm
OC organizationalUnit
MUST dc )

The dcOrganizationalUnitNameForm name form indicates that objects of
structural object class organizationalUnit have their RDN constructed
from a value of the attribute dc.

5.2.6.4 Name Form for Locality Objects

( 1.3.6.1.1.2.4
NAME dcLocalityNameForm
OC locality
MUST dc )

The dcLocalityNameForm name form indicates that objects of structural
object class locality have their RDN constructed from a value of the
attribute dc.

5.2.6.5 Name Form for Organizational Person Objects

( 1.3.6.1.1.2.5
NAME uidOrganizationalPersonNameForm
OC organizationalPerson
MUST uid )

The uidOrganizationalPersonNameForm name form indicates that objects
of structural object class organizationalPerson have their RDN
constructed from a value of the attribute uid.

6.0 Security Considerations

Although access controls may be placed on portions of the DIT to deny
browse access to unauthorized clients, it may be possible to infer
directory names and DIT structure in such sensitive portions of the
DIT from the results of DNS queries. Providing public visibility to
some portions of the DIT may assist those make such inferences.

7.0 Acknowledgments

This plan has emerged in the course of a number of fruitful
discussions, especially with David Chadwick, John Dale, Joe Gajewski,
Mark Jackson, Ryan Moats, Tom Spencer and Chris Tzu.

8.0 References

[1] Kille, S., Wahl, M., Grimstad, A., Huber, R., and S.
Sataluri, "Using Domains in LDAP Distinguished Names", RFC
2247, January 1998.

[2] X.500: The Directory -- Overview of Concepts, Models, and
Service, CCITT Recommendation X.500, December, 1988.

[3] Barker, P., and S. Kille, "The COSINE and Internet X.500
Schema", RFC1274, November 1991.

[4] The North American Directory Forum, "A Naming Scheme for
c=US", RFC1255, September 1991.

[5] The North American Directory Forum, "NADF Standing Documents:
A Brief Overview", RFC1417, February 1993.

[6] Yeong, W., Howes, T., and S. Kille, "Lightweight Directory
Access Protocol", RFC1777, March 1995.

[7] Wahl, M., Howes, T., and S. Kille, "Lightweight Directory
Access Protocol (v3)", RFC2251, December 1997.

[8] Kille, S., "A String Representation of Distinguished Names",
RFC1779, March 1995.

[9] Wahl, M., Kille, S., and T. Howes, "Lightweight Directory
Access Protocol (v3): UTF-8 String Representation of
Distinguished Names", RFC2253, December 1997.

[10] Wahl, M., "A Summary of the Pilot X.500 Schema for use
in LDAPv3", Work in Progress.

[11] Wahl, M., "A Summary of the X.500 User Schema for use with
LDAPv3", RFC2256, December 1997.

[12] Howes, T., and M. Wahl, "Referrals and Knowledge References
in LDAP Directories", Work in Progress.

[13] Howes, T., and M. Smith, "The LDAP URL Format", RFC2255,
December 1997.

[14] Wahl, M., Coulbeck, A., Howes, T., and S. Kille,
"Lightweight Directory Access Protocol (v3): Attribute Syntax
Definitions", RFC2252, December 1997.

[15] Smith, M., "Definition of the inetOrgPerson Object Class",
Work in Progress.

12. Authors' Addresses

Al Grimstad
AT&T
Room 1C-429, 101 Crawfords Corner Road
Holmdel, NJ 07733-3030
USA

EMail: alg@att.com

Rick Huber
AT&T
Room 1B-433, 101 Crawfords Corner Road
Holmdel, NJ 07733-3030
USA

EMail: rvh@att.com

Sri Sataluri
Lucent Technologies
Room 4D-335, 101 Crawfords Corner Road
Holmdel, NJ 07733-3030
USA

EMail: srs@lucent.com

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

EMail: M.Wahl@critical-angle.com

13. Full Copyright Statement

Copyright (C) The Internet Society (1998). All Rights Reserved.

This document and translations of it may be copied and furnished to
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