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Network Working Group                                   H. AlvestrandRequest for Comments: 2148                                    UNINETTBCP: 15                                                       P. JurgCategory: Best Current Practice                               SURFnet                                                       September 1997Deployment of the Internet White Pages ServiceStatus of this Memo   This document specifies an Internet Best Current Practices for the   Internet Community, and requests discussion and suggestions for   improvements.  Distribution of this memo is unlimited.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.Alvestrand & Jurg        Best Current Practice                  [Page 1]

RFC 2148              Internet White Pages Service        September 1997     (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           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 inRFC 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.Alvestrand & Jurg        Best Current Practice                  [Page 2]

RFC 2148              Internet White Pages Service        September 1997   Note: there are other, not interconnected, address databases on 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 (seesection 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 sections3-7 below contain recommendations related to the   publication of information in the IWPS that are independent of a   directory services protocol. The sections8-11 discuss X.500 specific   issues. Insection 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   -    The individual is enrolled in the university/school that        maintains the data   -    The individual is a (personal) subscriber of the maintainer's        Internet serviceAlvestrand & Jurg        Best Current Practice                  [Page 3]

RFC 2148              Internet White Pages Service        September 1997   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 (seesection 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, inRFC-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 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 addressAlvestrand & Jurg        Best Current Practice                  [Page 4]

RFC 2148              Internet White Pages Service        September 1997       -    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 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.Alvestrand & Jurg        Best Current Practice                  [Page 5]

RFC 2148              Internet White Pages Service        September 1997   -    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.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.Alvestrand & Jurg        Best Current Practice                  [Page 6]

RFC 2148              Internet White Pages Service        September 1997   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        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 toAlvestrand & Jurg        Best Current Practice                  [Page 7]

RFC 2148              Internet White Pages Service        September 1997   -    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 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 anAlvestrand & Jurg        Best Current Practice                  [Page 8]

RFC 2148              Internet White Pages Service        September 1997   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.   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.Alvestrand & Jurg        Best Current Practice                  [Page 9]

RFC 2148              Internet White Pages Service        September 1997   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 URLhttp://www.dante.net/nameflow.html10.  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 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)Alvestrand & Jurg        Best Current Practice                 [Page 10]

RFC 2148              Internet White Pages Service        September 199711.  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) 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.Alvestrand & Jurg        Best Current Practice                 [Page 11]

RFC 2148              Internet White Pages Service        September 199713.  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 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.Alvestrand & Jurg        Best Current Practice                 [Page 12]

RFC 2148              Internet White Pages Service        September 199714.  Acknowlegdements   The authors wish to thank the following people for their constructive   contributions to the text in this document:         Peter Bachman <peterb@suport.psi.com>         David Chadwick <D.W.Chadwick@iti.salford.ac.uk>         William Curtin <curtinw@ncr.disa.mil>         Patrik Faltstrom <paf@swip.net>         Rick Huber <rvh@att.com>         Thomas Lenggenhager <lenggenhager@switch.ch>         Sri Saluteri <sri@qsun.ho.att.com>         Mark Wahl <M.Wahl@critical-angle.com>15.  Glossary   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 inRFC 1777   Further terms may be found inRFC 1983.16.  References[1] Jeunik, E. and E. Huizer. Directory Services and Privacy     Issues. Proceedings of Joint European Networking Conference     1993, Trondheim,http://www.surfnet.nl/surfnet/diensten/x500/privacy.html[2]  Jennings, B. Building an X.500 Directory Service in the US,RFC1943, May 1996.[3]  Barker, P., S. Kille, T. Lenggenhager, Building Naming and     Structuring Guidelines for X.500 Directory Pilots, P.  Barker,     S. Kille, T. Lenggenhager,RFC1617Alvestrand & Jurg        Best Current Practice                 [Page 13]

RFC 2148              Internet White Pages Service        September 1997[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[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.[17] Key words for use in RFCs to Indicate Requirement Level, S.     Bradner,RFC 2119,Alvestrand & Jurg        Best Current Practice                 [Page 14]

RFC 2148              Internet White Pages Service        September 199717.  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.nlAlvestrand & Jurg        Best Current Practice                 [Page 15]