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.






Grimstad, et. al.            Informational                      [Page 1]

RFC 2377                A Directory Naming Plan           September 1998


  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.



Grimstad, et. al.            Informational                      [Page 2]

RFC 2377                A Directory Naming Plan           September 1998


  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.,

     [email protected]

  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.,

     [email protected], dc=acme, dc=com
     [email protected], dc=corporate, dc=acme, dc=com
     [email protected], 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.





Grimstad, et. al.            Informational                      [Page 3]

RFC 2377                A Directory Naming Plan           September 1998


  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






Grimstad, et. al.            Informational                      [Page 4]

RFC 2377                A Directory Naming Plan           September 1998


  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



Grimstad, et. al.            Informational                      [Page 5]

RFC 2377                A Directory Naming Plan           September 1998


  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



Grimstad, et. al.            Informational                      [Page 6]

RFC 2377                A Directory Naming Plan           September 1998


  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].



Grimstad, et. al.            Informational                      [Page 7]

RFC 2377                A Directory Naming Plan           September 1998


  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 [email protected], the uid
  attribute will be:

     [email protected]

  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 [email protected] the domain
  component attributes would typically be:

     dc=acme, dc=com

  The full LDAP DN for this user would then be:

     [email protected], 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:



Grimstad, et. al.            Informational                      [Page 8]

RFC 2377                A Directory Naming Plan           September 1998


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

           [email protected]

       may well be preferable to one such as:

           [email protected].

     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:

           [email protected]

       may well be preferable to one such as:

           [email protected]

  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.



Grimstad, et. al.            Informational                      [Page 9]

RFC 2377                A Directory Naming Plan           September 1998


  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:

     [email protected], 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:

     [email protected], 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 [email protected], but a
  subpopulation have mailboxes from an ISP and therefore mailboxes of
  the form [email protected].

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.



Grimstad, et. al.            Informational                     [Page 10]

RFC 2377                A Directory Naming Plan           September 1998


  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].









Grimstad, et. al.            Informational                     [Page 11]

RFC 2377                A Directory Naming Plan           September 1998


  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



Grimstad, et. al.            Informational                     [Page 12]

RFC 2377                A Directory Naming Plan           September 1998


  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.)



Grimstad, et. al.            Informational                     [Page 13]

RFC 2377                A Directory Naming Plan           September 1998


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.




Grimstad, et. al.            Informational                     [Page 14]

RFC 2377                A Directory Naming Plan           September 1998


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", RFC 1274, November 1991.

  [4]     The North American Directory Forum, "A Naming Scheme for
          c=US", RFC 1255, September 1991.

  [5]     The North American Directory Forum, "NADF Standing Documents:
          A Brief Overview", RFC 1417, February 1993.

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

  [7]     Wahl, M., Howes, T., and S. Kille, "Lightweight Directory
          Access Protocol (v3)", RFC 2251, December 1997.



Grimstad, et. al.            Informational                     [Page 15]

RFC 2377                A Directory Naming Plan           September 1998


  [8]     Kille, S., "A String Representation of Distinguished Names",
          RFC 1779, March 1995.

  [9]     Wahl, M., Kille, S., and T. Howes, "Lightweight Directory
          Access Protocol (v3): UTF-8 String Representation of
          Distinguished Names", RFC 2253, 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", RFC 2256, 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", RFC 2255,
          December 1997.

  [14]    Wahl, M., Coulbeck, A., Howes, T., and S. Kille,
          "Lightweight Directory Access Protocol (v3): Attribute Syntax
          Definitions", RFC 2252, December 1997.

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


























Grimstad, et. al.            Informational                     [Page 16]

RFC 2377                A Directory Naming Plan           September 1998


12.  Authors' Addresses

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

  EMail:  [email protected]


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

  EMail:  [email protected]


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

  EMail:  [email protected]


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

  EMail:  [email protected]















Grimstad, et. al.            Informational                     [Page 17]

RFC 2377                A Directory Naming Plan           September 1998


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
  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.
























Grimstad, et. al.            Informational                     [Page 18]