Internet Draft

        Best Current Practice for the Internet White Pages Service

                     Tue Apr 29 23:55:31 MET DST 1997


                         Harald Tveit Alvestrand
                                 UNINETT
                      Harald.T.Alvestrand@uninett.no





                                Peter Jurg
                                 SURFnet
                          Peter.Jurg@surfnet.nl






    Status of this Memo

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draft          BCP for the Internet White Pages Service       April 97


    1.  Summary and recommendations


    This document makes the following recommendations for
    organizations on the Internet:

     (1)   An organization SHOULD publish public E-mail addresses and
           other public address information about Internet users
           within their site.

     (2)   Most countries have laws concerning publication of
           information about persons. Above and beyond these, the
           organization SHOULD follow the recommendations of [1].

     (3)   The currently preferable way for publishing the information
           is by using X.500 as its data structure and naming scheme
           (defined in [4] and discussed in [3], but some countries
           use a refinement nationally, like [15] for the US). The
           organization MAY additionally publish it using additional
           data structures such as whois++.

     (4)   The organization SHOULD make the published information
           available to LDAP clients, by allowing LDAP servers access
           to their data".

     (5)   The organization SHOULD NOT attempt to charge for simple
           access to the data.

    In addition, it makes the following recommendations for various
    and sundry other parties:


     (1)   E-mail vendors SHOULD include LDAP lookup functionality
           into their products, either as built-in functionality or by
           providing translation facilities.

     (2)   Internet Service providers SHOULD help smaller
           organizations follow this recommendation, either by
           providing services for hosting their data, by helping them
           find other parties to do so, or by helping them bring their
           own service on-line.

     (3)   All interested parties SHOULD make sure there exists a core
           X.500 name space in the world, and that all names in this





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           name space are resolvable. (National name spaces may
           elobarate on the core name space).


    The rest of this document is justification and details for this
    recommendation.

    The words "SHOULD", "MUST" and "MAY", when written in UPPER CASE,
    have the meaning defined in RFC 2119 [17]


    2.  Introduction

    The Internet is used for information exchange and communication
    between its users. It can only be effective as such if users are
    able to find each other's addresses. Therefore the Internet
    benefits from an adequate White Pages Service, i.e., a directory
    service offering (Internet) address information related to people
    and organizations.

    This document describes the way in which the Internet White Pages
    Service (from now on abbreviated as IWPS) is best exploited using
    today's experience, today's protocols, today's products and
    today's procedures.

    Experience [2] has shown that a White Pages Service based on self-
    registration of users or on centralized servers tends to gather
    data in a haphazard fashion, and, moreover, collects data that
    ages rapidly and is not kept up to date.

    The most vital attempts to establish the IWPS are based on models
    with distributed (local) databases each holding a manageable part
    of the IWPS information. Such a part mostly consists of all
    relevant IWPS information from within a particular organization or
    from within an Internet service provider and its users. On top of
    the databases there is a directory services protocol that connects
    them and provides user access. Today X.500 is the most popular
    directory services protocol on the Internet, connecting the
    address information of about 1,5 million individuals and 3,000
    organizations. Whois++ is the second popular protocol. X.500 and
    Whois++ may also be used to interconnect other information than
    only IWPS information, but here we only discuss the IWPS features.

    Note: there are other, not interconnected, address databases on





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    the Internet that are also very popular for storing address
    information about people. "Ph" is a popular protocol for use with
    a stand-alone database.  There are over 300 registered Ph
    databases on the Internet. Interconnection of databases however,
    is highly recommended for an IWPS, since it ensures that data can
    be found. Hence Ph as it is now is not considered to be a good
    candidate for an IWPS, but future developments may change this
    situation (see section 12).

    Currently X.500 must be recommended as the directory services
    protocol to be used for the IWPS. However, future technology may
    make it possible to use other protocols as well or instead.

    Since many people think that X.500 on the Internet will be
    replaced by other protocols in the near future, it should be
    mentioned here that currently LDAP is seen as the surviving
    component of today's implementations and the main access protocol
    for tomorrow's directory services. As soon as new technology (that
    will probably use LDAP) becomes available and experiments show
    that they work, this document will be updated.

    A summary of X.500 products can be found in [14] (a document that
    will be updated regularly).

    The sections 3-7 below contain recommendations related to the
    publication of information in the IWPS that are independent of a
    directory services protocol. The sections 8-11 discuss X.500
    specific issues. In section 12 some future developments are
    discussed as they can be foreseen at the time of writing this
    document.



    3.  Who should publish IWPS information and how?

    IWPS information is public address information regarding
    individuals and organizations. The IWPS information concerning an
    individual should be published and maintained by an organization
    that has a direct, durable link with this individual, like in the
    following cases:


    -    The individual is employed by the maintainer's organization






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    -    The individual is enrolled in the university/school that
         maintains the data

    -    The individual is a (personal) subscriber of the maintainer's
         Internet service

    The organization that maintains the data does not have to store
    the data in a local database of its own. Though running a local
    database in the X.500 or Whois++ service is not a too difficult
    job, it is recommended that Internet service providers provide
    database facilities for those organizations among its customers
    that only maintain a small part of the IWPS information or don't
    have enough system management resources. This will encourage such
    organizations to join the IWPS. Collection of IWPS information and
    keeping it up-to-date should always be in the hands of the
    organization the information relates to.

    Within the current (national) naming schemes for X.500, entries of
    individuals reside under an organization. In the case of Internet
    service providers that hold the entries of their subscribers this
    would mean that individuals can only be found if one knows the
    name of the service provider.  The problem of this restriction
    could be solved by using a more topographical approach in the
    X.500 naming scheme, but will more likely be solved by a future
    index service for directory services, which will allow searches
    for individuals without organization names (see section 12).


    4.  What kind of information should be published?

    The information to be published about an individual should at
    least include:

    -    The individual's name

    -    The individual's e-mail address, in RFC-822 format; if not
         present, some other contact information is to be included

    -    Some indication of the individual's relationship with the
         maintainer

    When X.500 is used as directory services protocol the last
    requirement may be fulfilled by using the "organizationalStatus"
    attribute (see [3]) or by adding a special organizational unit to





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    the local X.500 name space that reflects the relation (like
    ou=students or ou=employees).

    Additionally some other public address information about
    individuals may be included in the IWPS:

    -    The individual's phone number

    -    The individual's fax number

    -    The individual's postal address

    -    The URL of the individual's home page on the Web

    In the near future it will be a good idea to also store public key
    information.

    More information about a recommended Internet White Pages Schema
    is found in The Internet White Pages Schema [16]

    Organizations should publish the following information about
    themselves in the IWPS:

    -    The URL of the organizations home page on the Web

    -    Postal address

    -    Fax numbers

    -    Internet domain

    -    Various names and abbreviations for the organization that
         people can be expected to search for, such as the English
         name, and often the domain name of an organization.


    Organizations may also publish phone numbers and a presentation of
    themselves.


    5.  Data management

    Data management, i.e. collecting the IWPS information and keeping
    it up-to-date, is a task that must not be underestimated for





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    larger organizations. The following recommendations can be made
    with respect to these issues:


    -    An organization should achieve an executive level commitment
         to start a local database with IWPS information. This will
         make it much easier to get cooperation from people within the
         organization that are to be involved in setting up a
         Directory Service.

    -    An organization should decide on the kind of information the
         database should contain and how it should be structured. It
         should follow the Internet recommendations for structuring
         the information. Besides the criteria in the previous
         section, [3] and [4] should be followed if X.500 is used as
         directory services protocol.

    -    An organization should define criteria for the quality of the
         data in the Directory, like timeliness, update frequency,
         correctness, etc. These criteria should be communicated
         throughout the organization and contributing entities should
         commit to the defined quality levels.

    -    Existing databases within an organization should be used to
         retrieve IWPS and local information, to the greatest extent
         possible. An organization should involve the people who
         maintain those databases and make sure to get a formal
         written commitment from them to use their data source. The
         organization should rely on these people, since they have the
         experience in management and control of local, available
         data.

    -    The best motivation for an organization to join the IWPS is
         that they will have a local database for local purposes at
         the same time. A local database may contain more, not
         necessarily public, information and serve more purposes than
         is requested for in the IWPS. In connecting to the IWPS an
         organization must "filter out" the extra local information
         and services that is not meant for the public IWPS using the
         directory services protocol.









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    6.  Legal issues

    Most countries have privacy laws regarding the publication of
    information about people. They range from the relaxed US laws to
    the UK requirement that information should be accurate to the
    Norwegian law that says that you can't publish unless you get
    specific permission from the individual. Every maintainer of IWPS
    information should publish data according to the national law of
    the country in which the local database which holds the
    information resides.

    Some of these are documented in [5] and [1].

    A maintainer of IWPS information should also follow some common
    rules, even when they are not legally imposed:

    -    Publish only correct information.

    -    Give people the possibility to view the information stored
         about themselves and the right to withhold information or
         have information altered.

    -    Don't publish information "just because it's there". Publish
         what is needed and what is thought useful, and no more.

    Given the number of data management and legal issues that are
    involved in publishing IWPS information, good consulting services
    are vital to have smaller companies quickly and efficiently join
    the IWPS. Internet service providers are encouraged to provide
    such services.


    7.  Do not charge for lookups

    In the current IWPS it believed that due to today's technological
    constraints, charging users is harmful to the viability of the
    service.  There are several arguments for this belief:

    -    Micropayment technology is not available at the moment.

    -    Subscription services require either that the customer sign
         up to multiple search services or that the services are
         linked "behind the scene" with all kinds of bilateral
         agreements; both structures have unacceptably high overhead





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         costs and increase the entry cost to the service.

    -    The current directory services protocols do not support
         authentication to a level that would seem appropriate for a
         service that charges.

    Therefore it is strongly recommended that all lookups by users in
    the IWPS are for free.  This, of course, does not limit in any way
    the ability to use the same IWPS dataset to support other services
    where charging may be appropriate.



    8.  Use X.500

    The IWPS based on the X.500 protocol has a relatively wide
    deployment. The current service contains about 1,5 million entries
    of individuals and 3,000 of organizations. It is coordinated by
    Dante, an Internet service provider in the UK, and known as
    "NameFLOW-Paradise".

    Though X.500 is sometimes criticized by the fact that its
    functionality is restricted by the hierarchical naming structure
    it imposes, it provides a reasonably good functionality as has
    been shown in several pilots by organizations [5], [2], [6], [7]
    that are now running a production X.500 IWPS. User interfaces also
    determine the functionality the X.500 IWPS offers. Usually they
    offer lookups in the IWPS based on the following user input:

    -    The name of a person

    -    The name of an organization this person can be related to

    -    The name of a country

    As a result they will provide the publicly available information
    about the person in question. Most user interfaces offer the
    possibility to list organizations in a country and users in an
    organization to help users to make their choice for the input. It
    may also be possible to use part of the names as input or
    approximate names.

    Specific user interfaces can provide lookups based on other input,
    like e-mail addresses of people or postal addresses of





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    organizations. Such possibilities may however violate privacy
    laws. Providers of directory services services may then be held
    responsible.

    The X.500 naming scheme imposes the requirement on an
    interconnected IWPS that all entries stored in it must have unique
    names (the "naming scheme"). This is most easily fulfilled by
    registering all entries in a "naming tree" with a single root;
    this is the reason why the totality of information in an X.500
    IWPS is sometimes referred to as the "Directory Information Tree"
    or DIT.

    Organizations are strongly encouraged to use the X.500 protocol
    for joining the IWPS. The current service is based on the X.500
    1988 standard [8] and some Internet-specific additions to the
    protocol that connects the local databases [10] and to the access
    protocol [9]. Organizations should use X.500 software based on
    these specifications and additionally supports [11] for the
    transportation of OSI protocols over the Internet.

    Organisations may connect to the NameFLOW-Paradise infrastructure
    with 1988 DSAs that don't implement [10], but they will lack
    automatic replication of knowledge references. This will be
    inconvenient, but not a big problem. The 1993 standard of X.500
    includes the functionality from [10], but uses a different
    potocol. Hence organisations that connect to the infrastructure
    with a 1993 DSA will also encounter this shortcoming. Section 12
    "Future developments" explains why the infrastructure doesn't use
    the 1993 standard for the moment.

    For recommendations on which attributes to use in X.500 and how to
    use them (either for public IWPS information or additional local
    information the reader is referred to [3] and [4]. For specific
    non-public local purposes also new attributes (and object classes)
    may be defined.  Generally it should be recommended to use as much
    as possible the multi-valuedness of attributes in X.500 as this
    will improve the searching functionality of the service
    considerably. For example, the organizationalName attribute which
    holds the name of an organization or the commonName attribute
    which holds the name of a person should contain all known aliases
    for the organization or person. In particular it is important to
    add "readable" variants of all attributes that people are expected
    to search for, if they contain national characters.






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    Another recommendation that can be made is that replication of
    data [10] between local databases is used in order to improve the
    performance of the service. Since replicating all entries of a
    part of the IWPS from one local database in another may violate
    local privacy laws, it is recommended to restrict replication to
    country and organizational entries and knowledge references (which
    tell where to go for which part of the IWPS). Of course privacy
    laws are not violated when the replicating database is managed by
    the same organization as the one that masters the information. So
    local replication between two databases within the same
    organization is highly recommended.

    In general replication within one country will usually be less a
    legal problem than across country borders.

    Recommendations for the operation of a database in the X.500
    infrastructure can be found in [12].

    X.500 is not recommended to be used for:


    -    A Yellow Pages service with a large scope. See [5].

    -    Searching outside the limited patterns listed here, in
         particular searching for a person without knowing which
         organization he might be affiliated to.

    -    Publishing information in other character sets than ASCII,
         some of the Latin-based European scripts and Japanese (the
         T.61 character sets). While support for these character sets
         is available in revised versions of X.500, products that
         support the revision aren't commonly available yet.

    9.  Use the global name space

    Some people, for instance when using Novell 4 servers, have
    decided that they will use X.500 or X.500-like services as an
    internal naming mechanism, without coordinating with an outside
    source.

    This suffers from many of the same problems as private IP
    addresses, only more so: your data may need significant
    restructuring once you decide to expose them to the outer world.






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    A globally accessible X.500 service requires a globally connected
    X.500 name space. See [3] and [4] for recommendations on how
    create a local part of the global name space.

    Though the standard is not very clear about this and the most
    recent version (93) appears not to support it, in practice the
    X.500 name space is only manageable if there is a single root
    context operated under a cooperative agreement. However, one can
    be sure that there will be turf battles over it's control.

    If those turf battles aren't decided outside the actual running
    service, the effect on the service quality will be ruinous.

    This document appeals to all players in the field to let existing
    practice alone until a better system is agreed and is ready to go
    into place; at the moment, the root context of the day is operated
    by the Dante NameFLOW-Paradise service.

    More information on the Dante NameFLOW-Paradise service is found
    at the URL

    http://www.dante.net/nameflow.html



    10.  Use LDAP

    At the moment, LDAP as documented in [9] is the protocol that
    offers the most X.500 functionality in places where it is not
    feasible to implement the full OSI stack.

    It is implemented on a lot of platforms, including several PC-type
    platforms, and is popular in a multitude of commercial offerings.

    A concerted effort to make LDAP available is the publication
    method that gives the widest access to the data.

    In addition, X.500 DSAs must implement the necessary linkages to
    make sure they are properly integrated into the naming/referral
    tree; in most cases, this will mean that they should implement the
    X.500 DSP protocol at least.

    (The question of whether one gateways LDAP to DAP or DAP to LDAP
    is irrelevant in this context; it may be quite appropriate to





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    store data on an LDAP-only server and make it available to the
    DAP/DSP-running world through a gateway if the major users all use
    LDAP)



    11.  Make services available

    The technical investment in running an X.500 service is not
    enormous, see for example [5].



    12.  Future developments

    Today [October 1996] there are several enhancements to be expected
    with respect to IWPS technology.

    The most important one to be mentioned here is the creation of a
    "Common Indexing Protocol" that must enable the integration of
    X.500, Whois++ and protocols that use stand-alone databases. Such
    a protocol would not only enable integration but would offer at
    the same time the possibility to explore yellow pages services and
    enhanced searches, even if used for X.500 only.

    In the context of the Common Indexing Protocol the stand-alone
    LDAP servers should be mentioned that are announced by several
    software developers. These are stand-alone address databases that
    can be accessed by LDAP. Currently also a public domain version is
    available from the University of Michigan.  Also announced is an
    LDAP-to-DAP gateway that can integrate a stand-alone LDAP server
    in an X.500 infrastructure.

    Other improvements include defining a common core schema for
    multiple White Pages services, leading to the possibility of
    accessing data in multiple services through a single access
    protocol.

    The 1993 version of the X.500 standard has already been
    implemented in several products. It is an enhancement over the
    1988 standard in several ways, but has not been implemented in the
    NameFLOW-Paradise infrastructure yet.  The main reason is that the
    standard doesn't recognize the existence of a single root DSA, but
    assumes that the managers of first-level DSAs (the country DSA's)





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    make bilateral contracts for interconnection. In the case of
    NameFLOW-Paradise such a situation would be unmanageable. In [13]
    an enhancement of the 1993 standard is proposed that makes a
    single root possible. As soon as implementations of [13] are
    available, NameFLOW-Paradise will experiment with 1993 DSAs. This
    is expected in 1997.



    Once these developments reach stability, they may be referenced by
    later versions of this BCP document.


    13.  Security considerations

    The security implications of having a directory are many.


    -    People will have a standard way to access the information
         published.

    -    People will be able to gather parts of the information for
         purposes you never intended (like publishing directories,
         building search engines, headhunting or making harassing
         phone calls).

    -    People will attempt to access more of the information than
         you intended to publish, by trying to break security
         functions or eavesdropping on conversations other users have
         with the Directory.

    -    If modification over the Net is possible, people will attempt
         to change your information in unintended ways. Sometimes
         users will change data by mistake, too; not all undesired
         change is malicious.

    The first defense for directory security is to limit your
    publication to stuff you can live with having publicly available,
    whatever happens.

    The second defense involves trying to impose access control. LDAP
    supports a few access control methods, including the use of
    cleartext passwords. Cleartext passwords are not a secure
    mechanism in the presence of eavesdroppers; this document





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    encourages use of stronger mechanisms if modification is made
    available over the open Internet.  Otherwise, modification rights
    should be restricted to the local intranet.

    The third defense involves trying to prevent "inappropriate"
    access to the directory such as limiting the number of returned
    search items or refuse list operations where they are not useful
    to prevent "trolling". Such defenses are rarely completely
    successful, because it is very hard to set limits that
    differentiate between an innocent user doing wasteful searching
    and a malicous data troller doing carefully limited searches.

    Future enhancements may include using encrypted sessions, public
    key logins and signed requests; such mechanisms are not generally
    available today.


    14.  Acknowlegdements

    The authors wish to thank the following people fo their
    constructive contributions to the text in this document:


         Peter Bachman 

         David Chadwick 

         William Curtin 

         Patrik Faltstrom 

         Rick Huber 

         Thomas Lenggenhager 

         Sri Saluteri 

         Mark Wahl 


    15.  Glossary








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    DAP  Directory Access Protocol; protocol used between a DUA and a
         DSA to access the Directory Information. Part of X.500.

    DSP  Directory System Protocol: the protocol used between two DSAs

    DSA  Directory System Agent - entity that provides DUAs and other
         DSAs access to the information stored in the Directory

    LDAP Lightweight Directory Access Protocol - defined in RFC 1777

    Further terms may be found in RFC 1983.


    16.  References


    [1]  Directory Services and Privacy Issues, E. Jeunik and E.
         Huizer.  Proceedings of Joint European Networking Conference
         1993, Trondheim

    [2]  Building an X.500 Directory Service in the US, B. Jennings,
         RFC1943

    [3]  Building Naming and Structuring Guidelines for X.500
         Directory Pilots, P.  Barker, S. Kille, T. Lenggenhager,
         RFC1617

    [4]  The COSINE and Internet X.500 Schema. P. Barker & S. Kille,
         RFC1274

    [5]  Introducing a Directory Service, SURFnet report 1995 (see
         URL:
         http://info.nic.surfnet.nl/surfnet/projects/x500/introducing/)

    [6]  Paradise International Reports, University College London,
         April 1991 - April 1994

    [7]  Naming Guidelines for the AARNet X.500 Directory Service,
         Michaelson and Prior, RFC 1562

    [8]  CCITT Blue Book, Volume VIII - Fascicle VIII.8, November 1988

    [9]  Lightweight Directory Access Protocol, W. Yeong, T. Howes, S.
         Kille, RFC1777





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    [10] Replication and Distributed Operations extensions to provide
         an Internet Directory using X.500, S. Kille, RFC1276

    [11] ISO transport services on top of the TCP: Version: 3, M.
         Rose, D. Cass, RFC1006

    [12] Recommendations for an X.500 Production Directory Service, R.
         Wright et al., RFC1803

    [13] Managing the X.500 Root Naming Context, D. Chadwick, RFCxxxx

    [14] A Revised Catalog of Available X.500 Implementations, A.
         Getchell, S.  Sataluri, RFC1632

    [15] A Naming Scheme for c=US, The North American Directory Forum,
         RFC1255

    [16] A Common Schema for the Internet White Pages Service, T.
         Genovese, B. Jennings, Work In  Progress [draft-ietf-ids-
         iwps-schema-spec-03.txt]

    [17] Key words for use in RFCs to Indicate Requirement Level, S.
         Bradner, RFC 2119

    17.  Authors address

    Harald Tveit Alvestrand
    UNINETT
    P.O.Box 6883 Elgeseter
    N-7002 TRONDHEIM
    NORWAY

    +47 73 59 70 94
    Harald.T.Alvestrand@uninett.no

    Peter Jurg
    SURFnet
    P.O.Box 19035
    NL-3501 DA UTRECHT
    THE NETHERLANDS

    +31 30 2305305
    Peter.Jurg@surfnet.nl






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