GENWiki

Premier IT Outsourcing and Support Services within the UK

User Tools

Site Tools


rfc:rfc1943

Network Working Group B. Jennings Request for Comments: 1943 Sandia National Laboratory Category: Informational May 1996

           Building an X.500 Directory Service in the US

Status of this Memo

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

Abstract

 This document provides definition and recommends considerations that
 must be undertaken to operate a X.500 Directory Service in the United
 States.  This project is the work performed for the Integrated
 Directory Services Working Group within the Internet Engineering Task
 Force, for establishing an electronic White Pages Directory Service
 within an organization in the US and for connecting it to a wide-area
 Directory infrastructure.
 Establishing a successful White Pages Directory Service within an
 organization requires a collaborative effort between the technical,
 legal and data management components of an organization. It also
 helps if there is a strong commitment from the higher management to
 participate in a wide-area Directory Service.
 The recommendations presented in the document are the result of
 experience from participating in the Internet White Pages project.

Table of Contents

 1.0     Introduction                                            2
 1.1     Purpose of this Document                                2
 1.2     Introduction to Directory Services                      2
 2.0     The X.500 Protocol                                      4
 2.1     Introduction                                            4
 2.2     Directory Model                                         4
 2.3     Information Model                                       5
 2.4     Benefits and Uses for X.500 Directory Service           6
 2.5     Other Applications of X.500                             7
 3.0     Legal Issues                                            8
 3.1     Introduction                                            8
 3.2     Purpose of the Directory                                8
 3.3     User Rights                                             9
 3.4     Data Integrity                                          9

Jennings Informational [Page 1] RFC 1943 Building an X.500 Directory Service in the US May 1996

 3.5     Protection of the Data                                 10
 3.6     Conclusions                                            10
 4.0     Infrastructure                                         11
 4.1     Introduction                                           11
 4.2     A Well Maintained Infrastructure                       11
 4.3     DUA Interfaces for End Users                           12
 5.0     Datamanagement & Pilot Projects                        13
 5.1     Simple Internet White Pages Service                    13
 5.2     InterNIC                                               13
 5.3     ESnet                                                  14
 6.0     Recommendations                                        14
 6.1     General                                                14
 6.2     Getting Started                                        14
 6.3     Who are the Customers                                  14
 6.4     What are the Contents of the Directory                 15
 6.5     What are the Rights of the Individuals                 15
 6.6     Data Integrity                                         16
 6.7     Data Security                                          16
 6.8     Data Administration                                    17
 6.9     Conclusion                                             17
 7.0     References                                             18
 8.0     Glossary                                               19
 9.0     Security Considerations                                22
 10.0    Author's Address                                       22

1.0 Introduction

1.1 Purpose of this Document

 This document provides an introduction for individuals planning to
 build a directory service for an organization in the US. It presents
 an introduction to the technical, legal, and organizational aspects
 of a directory service. It describes various options to organizations
 who want to operate an X.500 Directory service and illustrates these
 with examples of current X.500 service providers.

1.2 Introduction to Directory Services

 An electronic directory server is an electronic process that provides
 a list of information provided via electronic access. This
 information is variable in content, however it should be explicitly
 defined by the directory purpose. Information about people,
 organizations, services, network hardware are just a few examples of
 data content that a directory service can provide. The aim of an
 X.500 Directory service is to make using the directory intuitive and
 as easy to use as calling for directory assistance. The X.500
 Directory service is an international standard ratified by the
 International organization for Standardization (IS) and the ITU-T

Jennings Informational [Page 2] RFC 1943 Building an X.500 Directory Service in the US May 1996

 International Telecommunication Union formerly (CCITT) in 1988 [1].
 The Directory is intended to be global service comprised of
 independently operated and distributed Directory Service Agents
 (DSAs), that provide information in the form of a White Pages Phone
 Directory.
 Electronic mail communication benefits from the existence of a global
 electronic White Pages to allow network users to retrieve addressing
 information in an intuitive fashion. Manual searching for names and
 addresses, specifically electronic addresses, can take a great deal
 of time. A White Pages directory service can enable network users to
 retrieve the addresses of communication partners in a user friendly
 way, using known variables such as common name, surname, and
 organization to facilitate various levels of searches.
 In order to make global communication over computer networks work
 efficiently, a global electronic White Pages service is
 indispensable. Such a directory service could also contain telephone
 and fax numbers, postal addresses as well as platform type to
 facilitate in translation of documents between users on different
 systems. An electronic White Pages may prove to be useful for
 specific local purposes; replacing paper directories or improving
 quality of personnel administration for example. An electronic
 directory is much easier to produce and more timely than paper
 directories which are often out of date as soon as they are printed.
 The Internet White Pages Project provides many companies in the US
 with an opportunity to pilot X.500 in their organizations.
 Operating as a globally distributed directory service, this project
 allows organizations in a wide variety of industry type to make
 themselves known on the Internet and to provide access to their staff
 as desired.
 Some organizations, such as ESnet agreed to manage directory
 information for other organizations. ESnet maintains data at their
 site for all the national laboratories. They provide assistance to
 organizations in defining their directory information tree (DIT)
 structure. They also provide free access to the X.500 Directory via
 Gopher, WWW, DUAs, whois and finger protocols.
 The InterNIC is another directory services provider on the Internet.
 To date [June 1995] they hold X.500 directory data for 52
 organizations and provide free access to this data via various
 protocols: X.500 DUA, E-Mail, whois, Gopher and WWW.
 To find the most current listing of X.500 providers see RFC 1632 -
 Catalog of Available X.500 Implementations [2].

Jennings Informational [Page 3] RFC 1943 Building an X.500 Directory Service in the US May 1996

2.0 The X.500 Protocol

2.1 Introduction

 This chapter provides the basic technical information necessary for
 an organization to begin deploying an X.500 Directory Service. It
 provides a brief introduction to the X.500 protocol and the
 possibilities that X.500 offers.

2.2 The Directory Model

 X.500 Directory Model is a distributed collection of independent
 systems which cooperate to provide a logical data base of information
 to provide a global Directory Service. Directory information about a
 particular organization is maintained locally in a Directory System
 Agent (DSA). This information is structured within specified
 standards. Adherence to these standards makes the distributed model
 possible. It is possible for one organization to keep information
 about other organizations, and it is possible for an organization to
 operate independently from the global model as a stand alone system.
 DSAs that operate within the global model have the ability to
 exchange information with other DSAs by means of the X.500 protocol.
 DSAs that are interconnected form the Directory Information Tree
 (DIT). The DIT is a virtual hierarchical data structure. An X.500
 pilot using QUIPU software introduced the concept of a "root" DSA
 which represents the world; below which "countries" are defined.
 Defined under the countries are "organizations". The organizations
 further define "organizational units" and/ or "people". This DIT
 identifies the DIT for the White Pages X.500 services.
 Each DSA provides information for the global directory. Directories
 are able to locate in the hierarchical structure discussed above,
 which DSA holds a certain portion of the directory. Each directory
 manages information through a defined set of attributes and in a
 structure defined as the Directory Information Base (DIB).
 A DSA is accessed by means of a Directory User Agent (DUA). A DUA
 interacts with the Directory by communicating with one or more DSAs
 as necessary to respond to a specific query. DUAs can be an IP
 protocol such as whois or finger, or a more sophisticated application
 which may provide Graphical User Interface (GUI) access to the DSA.
 Access to a DSA can be accomplished by an individual or automated by
 computer application.

Jennings Informational [Page 4] RFC 1943 Building an X.500 Directory Service in the US May 1996

2.3 The Information Model

 In addition to the Directory Model, the X.500 standard defines the
 information model used in the Directory Service. All information in
 the Directory is stored in "entries", each of which belong to at
 least one "object class". In the White Pages application of X.500
 object classes are defined as country, organization, organizational
 unit and person.
 The object classes to which an entry belongs defines the attributes
 associated with a particular entry. Some attributes are mandatory
 others are optional. System administrators may define their own
 attributes and register these with regulating authorities, which will
 in turn make these attributes available on a large scale.
 Every entry has a Relative Distinguished Name (RDN), which uniquely
 identifies the entry. A RDN is made up of the DIT information and the
 actual entry.
 The Directory operates under a set of rules know as the Directory
 schema.  This defines correct utilization of attributes, and ensures
 an element of sameness throughout the global Directory Service.
 Under the White Pages object class "Person" there are three mandatory
 attributes:
      objectClass     commonName      surName
 These attributes along with the DIT structure above, define the RDN.
 An example of an entry under Sandia National Laboratory is shown
 here: @c=US@o=Sandia National Laboratory@ou=Employees@cn=Barbara
 Jennings
                                 root
                                 /  \
                                /    \
                              c=US    c=CA
                              /  \
                             /    \
                o=Sandia National   o=ESnet
                  Laboratory
                 /   \
                /     \
          ou=Employees  ou=Guests
            /                \
           /                  \
   cn=Barbara Jennings        cn=Paul Brooks

Jennings Informational [Page 5] RFC 1943 Building an X.500 Directory Service in the US May 1996

 Organizations may define the best structure suited for their DIT.
 Typically an organizations DIT will look very much like the
 organizations structure itself. A DIT structure is determined by
 naming rules and as such, becomes the elements unique Relative
 Distinguished Name (RDN). The DIT structure may also be dependent on
 whether the DSA information is administered by a flat file or a
 database. Extra consideration to designing of the DIT structure
 should be taken when using flat files versus a database, as it takes
 longer to search through a flat file if the tree structure becomes
 too complex or intricate. To obtain information on recommended schema
 for DIT structuring see RFC1274 [3].

2.4 Benefits and Uses for X.500 Directory Service

 The nature of the X.500 Directory makes it suitable for independently
 operated segments that can be expanded to global distribution. The
 benefits for local directory use are:
  1. with the distributed nature of the service, an organization may

separate the responsibility for management of many DSAs and still

 retain the overall structure;
  1. the robustness of this service allows it to provide information to a

wide range of applications. Whereas globally integrated projects must

 conform to a specific DIT, independent X.500 operations may define
 unique DITs, object classes and attributes as per their specific
 needs;
  1. X.500 is a good alternative for paper directories, offering the

ability to update and modify in an interactive mode. This allows a

 company to provide the most current information with less cost and
 effort;
  1. because of the electronic base of X.500, other electronic

applications may interact with the application without human

 intervention.
 The benefits for global directory use are:
  1. the distributed nature of X.500 is well suited for large global

applications such as the White Pages Directory. Maintenance can be

 performed in a distributed manner;
  1. X.500 offers good searching capabilities from any level in the DIT.

Also with "User Friendly Naming" in place, searches are very

 intuitive;

Jennings Informational [Page 6] RFC 1943 Building an X.500 Directory Service in the US May 1996

  1. there are DUA interfaces for the White Pages service available for

all types of workstations. For an overview of X.500 software reference

 RFC1632.
  1. X.500 is an international standard. Using such a standard ensures

interoperability within the worldwide base.

2.5 Other Applications of X.500

 In addition to the White Pages, X.500 can be used as a source for any
 type of information that needs a distributed storage base.
 The University of Michigan is using X.500 for electronic mail
 routing. Any mail coming to the university domain, umich.edu; gets
 expanded out to a local address that is stored in the rfc822Mailbox
 attribute. The University also operates a standard X.500 name server
 which provides name lookup service of over 200,000 names. They use
 the Lightweight Directory Access Protocol (LDAP) [11].
 An implementation of the X.500 Standard directory service has been
 incorporated into the Open Software Foundation (OSF) Distributed
 Computing Environment (DCE). This component, known as the Global
 Directory Service (GDS), provides an area where distributed
 application clients can find their application servers. The GDS, in
 response to requests made by other clients, provides the unique
 network address for a particular DCE resource.  Because it is based
 on a international standard, GDS can offer access to resources among
 users and organizations worldwide. This scalable service can be
 performed in DCE environments that range in size from the very small
 to the very large.
 Lookup services can be implemented into a variety of applications.
 Cambridge University in Great Britain implemented the X.500 directory
 service into an employee locator application. Based on badge sensors
 at strategic locations, this application can determine the
 whereabouts of an employee on the campus. As the individual moves
 about, the sensors register their location in an X.500 Directory.
 Digital Signature Service (DSS) and Privacy Enhanced Mail (PEM) work
 on the principal of a directory key server which generates and
 provide users with "public" codes that match previously registered
 "private" codes. Only the recipient can decipher messages sent in
 this fashion. The X.509 [4] standard for key certificates easily fits
 within the structure of the X.500 Directory Service.

Jennings Informational [Page 7] RFC 1943 Building an X.500 Directory Service in the US May 1996

3.0 Legal Issues

3.1 Introduction

 Currently in the United States, there are no specific legal rules for
 the information that is provided via an electronic directory service.
 Various organizations and groups associated with usage of the
 Internet, noting a need to address privacy and data integrity issues,
 have prepared directives to address this issue. Two such areas
 addressed are those of the rights of registrants included in the
 directory and the responsibility of administrators to guarantee the
 integrity of such data.
 Registries containing information that is related to an individual is
 freely transferred and unregulated in the US, unless the provider of
 the data is an agency or an holder of sensitive information as
 defined by federal legislation and further may differ for each state.
 An agency is defined as: any executive department, military
 department, Government corporation, Government controlled
 corporation, or other establishment in the executive branch of the
 Government (including the Executive Office of the President), or any
 independent regulatory agency. Sensitive data can be financial
 records, medical records, and certain legal documents. As previously
 noted, each state has their own legislation on sensitive or private
 data.The registered persons have little recourse to control list
 information short of filing a lawsuit against the information
 provider.
 For individuals who transfer data across country boundaries, it is
 important to understand that other countries may have legislation to
 regulate data. Prior to requesting list information from these
 countries, an administrator should review applicable legislation and
 have some mechanism in place to ensure how data will be handled once
 it is crosses the border. Policy Statements for some countries have
 been prepared and are provided for via Code of Conduct papers.

3.2 Purpose of the Directory

 The operational intent including presentation data and list
 registrants and access rights must be clearly defined and stated.
 Initially this provides the skeleton of the DIT. Eventually a
 statement such as this may provide a basis legally justifying the
 directory.
 All data presented must be defined in the purpose. If for example, a
 directory is for the sole purpose of providing professional
 addressing information - an entry would include name, postal address,
 office telephone, facsimile number, electronic mail address and

Jennings Informational [Page 8] RFC 1943 Building an X.500 Directory Service in the US May 1996

 company name.  Private address information listing the home address
 or phone would be prohibited as would any other information not
 directly related to addressing.

3.3 User Rights

 The North American Directory Forum (NADF) has published a document
 that defines the User Bill of Rights [5]. This document defines an
 individuals rights regarding the public release of personal or
 private information.  Among other issues stated, the user has the
 right to be notified regarding the inclusion of their information in
 a data registry as well as the right to examine and have incorrect
 information changed.
 This paper is specifically written for the North American Directory
 Forum and recommends compliance with US or Canadian laws regulating
 privacy and access information.
 Although current US legislation does not include all the suggestions
 in this document, it is the responsibility of the controller of the
 data to respect the rights of the individuals. These recommended
 rules can be seen as respect for the individual and the considerate
 controller will follow these guidelines within any boundaries that
 they may be mandated by.

3.4 Data Integrity

 An information provider has the responsibility to guarantee the data
 that they make available to users. The integrity of a data source is
 heavily weighted by the accuracy and timeliness of the contents.
 Interoperable data sources must have concurrence of these factors as
 well. The degree to which an information provider can guarantee the
 validity of the data that they present, reflects on the validity of
 the provider in general. RFC 1355 [6], suggests that a data source
 enable accuracy statements describing the process that the individual
 NIC will use to maintain accuracy in the database.
 In the European community, it is a legal requirement that the
 information provider guarantee accurate data.
 The controller of the information needs to be certain of the primary
 source of data. When possible, the controller should develop routines
 of random checks to validate the registry data for correctness.

Jennings Informational [Page 9] RFC 1943 Building an X.500 Directory Service in the US May 1996

3.5 Data Security

 A Directory Service with non-authenticated access from the Internet
 is difficult to protect from unauthorized use. Unauthorized use being
 defined by each organization within the directory purpose statement.
 Typical misuse being by individuals who attempt to duplicate the
 directory for unauthorized purposes. Other security measures include:
 Access Control Lists (ACLs), limitations on number of entries
 returned to a query, and time to search flags. The result of such
 controls will affect the legitimate user as well as the user they are
 intended to block.
 An alternative that may provide protection from misuse is to create
 and display an attribute with each entry stating non-approved usage.
 This feature will also provide evidence of restricted use in the
 event that a legal case is necessary to stop unauthorized access.
 The responsibility again falls on the data provider/implementor of
 the directory service. Astute programmers will create or make use of
 existing tools to protect against data destruction, falsification,
 and misuse.

3.6 Conclusions

 User Rights, Data Integrity and Protection of data should not be
 considered merely in an effort to abide by legal rulings; they should
 be the intention of a good data source. A successful Directory
 Service must be aware of the requirements of those individuals
 inclusive in the list as well as those of the directory users.
 In general, at the minimum the following conditions should be
 observed:
      1. Define the purpose of the Directory.
      2. Initially inform all registrants of their inclusion in
         a Directory.
      3. Prevent the use of data beyond the stated purpose.
      4. Limit the attributes associated to an entry within
         boundaries of the purpose.
      5. Work towards a suitable level of security.
      6. Develop a mechanism to correct/remove faulty data
         or information that should not be in the Directory.

Jennings Informational [Page 10] RFC 1943 Building an X.500 Directory Service in the US May 1996

4.0 Infrastructure

4.1 Introduction

 The White Pages Project, currently operated by Performance Systems
 International (PSI) provides a reliable QUIPU infrastructure for
 sites wishing to provide their own X.500 directory. Started in 1989
 as the NYSERNet White Pages Pilot Project it was the first
 production-quality field test of the Open Systems Interconnection
 (OSI) technology running on top of TCP/IP suite of protocols [7].
 This pilot X.500 Directory, provided a real-time testbed for a
 variety of administrative and usage issues that arise. Today, more
 than 30 countries participate in the globally distributed project
 with over 1 million entries. The White Pages pilot is one of 37 other
 pilots cooperating to provide information in the Nameflow-PARADISE
 directory; an European project.
 Initially the software was public domain, QUIPU X.500 [8]. This
 "shareware" application in conjunction with administrative services
 provided free of charge by PSI, allowed for a truly distributed X.500
 Directory Service to operate.
 In keeping with the Internet rules of operation, the lack of the US
 regulations, the suggestions of North American Directory Forum and
 the Internet Engineering Task Force (IETF), the complications that
 arise from multi-distributed data as a service can be overwhelming.
 PSI took on the challenge to provide such a service, and continues to
 ensure operations today.

4.2 A Well Maintained Infrastructure

 This distributed information service involves the cohesive effort of
 all of the participating organizations. The ISO Development
 Environment (ISODE) implementation of the OSI Directory, provided the
 attributes and uniformity to facilitate this effort.
 The primary DSA for the PSI Project is named Alpaca. Operating on a
 Sun Sparc 10 with 120 megabytes of memory, this host serves as the
 Master for the DSAs of 117 organizations under c=US. Redundancy for
 Alpaca is provided by two sources, Fruit Bat operated by PSI and Pied
 Tamarin operated by the InterNIC. Slave updates to this host are
 provided on a nightly basis from the individual DSAs.
 The data presentation is hierarchical in nature and emulates the
 common white pages telephone book. The information provided contains
 at minimum: a common name, voice phone listing, and electronic mail
 addressing. Each entry has a uniqueness associates with it; the
 relative distinguished name which is comprised of the entire

Jennings Informational [Page 11] RFC 1943 Building an X.500 Directory Service in the US May 1996

 directory information tree. The DITs may vary slightly, but each must
 contain an organization, and a person. The nature of the directory
 and the structure of the actual organization for whom the directory
 is being provided contribute to the overall DIT structure. The
 following is a list of commonly used attributes:

commonName physicalDeliveryOfficeName stateOrProvinceName description photo streetAddress userid postOfficeBox surname favouriteDrink postalAddress telephoneNumber title rfc822Mailbox facsimileTelephoneNumber

4.3 DUA Interfaces for End Users

 There are a variety of user interfaces on the market today that will
 provide Directory User Agent access to the X.500 Directory. Standard
 protocols such as fred, whois, whois++, finger, are used widely.
 Interfaces are also available via World-wide Web browsers and
 electronic mail.
 Vendors providing DUAs include ISODE Consortium, NeXor, and Control
 Data Corporation. These applications operate in conjunction with the
 vendor provided DSAs.
 Historically DUA interfaces were difficult to implement and required
 the entire OSI stack. Implementing such a product on a PC or Apple
 platform required skillful programming. The executable for these
 platforms were usually very large. The IETF has since defined and
 standardized the Lightweight Directory Access Protocol (LDAP) [11]; a
 protocol for accessing on-line Directory services which offers
 comparable functionality to the Directory Access Protocol (DAP). It
 runs directly over TCP and is used by nearly all X.500 clients. LDAP
 does not have the overhead of the various OSI layers and runs on top
 of TCP/IP.
 The functionality varies by specific DUA. Each offers access to the
 X.500 Directory. Most offer the ability to make modifications to
 entries. There are a few that offer Kerberos authentication.
 Further information on LDAP clients for specific platforms can be
 found on the University of Michigan WWW server:
 http://www.umich.edu/~rsug/ldap.
 Another interface that has been tested and recommended for users by
 our Dutch (Surfnet) colleagues is Directory Enquiry (DE). Originally
 developed by University College London for the Paradise project in
 Europe, the engineers at Surfnet have selected DE as the best
 interface for "dumb" terminals. They have also translated the

Jennings Informational [Page 12] RFC 1943 Building an X.500 Directory Service in the US May 1996

 interface into Dutch for their local users [12].
 Ideally, users should be able to access X.500 directly from their
 electronic mail applications. Vendors (other than the ones mentioned
 above) have been slow to incorporate the X.500 Standards into their
 electronic mail applications.

5.0 Datamanagement & Pilot Projects

5.1 Simple Internet White Pages Service

 A wide variety of directory services retrieval protocols has emerged
 in the time since the original Internet White Pages was begun in
 1989. To ensure that decentralized implementations will have
 interoperability with other providers, the IETF Integrated Directory
 Services Working Group, is working to create a draft focusing on the
 common information and operational modeling issues to which all
 Internet White Pages Services (IWPS) must conform to.
 Utilizing current information servers, the conceptual model described
 includes issues regarding naming, schema, query and response issues
 for a narrowly defined subset of directory services. The goal of this
 paper is to establish a simple set of information objects, coupled
 with a basic set of process requirements that will form a basis which
 can lead to ubiquitous IWPS. With this goal in mind, it will be
 easier to proved a consistent User view of the various directory
 services.

5.2 InterNIC

 The InterNIC [9] is a collaborative project of two organizations
 working together to offer the Internet community a full scope of
 network information services. Established in January 1993 by the
 National Science Foundation, the InterNIC provides registration
 services and directory and database services to the Internet.
 (Internet a global network of more than 13,000 computers networks,
 connecting over 1.7 million computers and used by an estimated 13
 million people.) In keeping up with the exponential growth of the
 Internet, the InterNIC provides a guide to navigate the maze of
 available resources.
 InterNIC provides two types of services; InterNIC directory and
 database services and registration services. AT&T provides the
 directory and database services, acting as the pointer to numerous
 resources on the network offering X.500 to help users easily locate
 other users and organizations on the Internet.

Jennings Informational [Page 13] RFC 1943 Building an X.500 Directory Service in the US May 1996

5.3 ESnet

 The Energy Sciences Network [10], is a nationwide computer data
 communications network whose primary purpose is support multiple
 program, open scientific research. As part of this support, ESnet
 offers networking services including information access and
 retrieval, directory services, group communications series, remote
 file access services and infrastructure services. As a early member
 of the White-Pages Pilot Project, ESnet continues to be a part of the
 worldwide distributed directory service based on the ISO/OSI X.500
 standard. There are over nineteen ESnet organization represented in
 the directory, comprising over 120,000 entries. ESnet provides access
 to seven other sites via the X.500 DSAs.

6.0 Recommendations

6.1 General

 The X.500 Directory technology is available through several options.
 Vendors can provide consultation for schema design as well as supply,
 install, and support the software to perform the operations required.
 For smaller organizations or companies who do not want to administer
 their own DSA, there are providers available who will maintain the
 DSAs remotely and provide this service to the Internet. Those with
 network and management expertise, can either operate independently or
 join one of several white pages directory projects. Careful
 consideration must be given to the initial investment required and
 the required maintenance process.

6.2 Getting Started

 Successful initialization of a directory service requires a
 systematic approach. The complexity of offering this type of service
 becomes more apparent as implementation progresses. Several aspects
 must be considered as this service becomes a cooperative effort among
 the technical, administrative, organizational, and legal disciplines.
 Procedures must be defined and agreed to at the initial phase of
 implementing an X.500 Directory service [13].  The following are
 issues that should be addressed in these procedures.

6.3 Who are the Customers?

 Defining the customer and the customer requirements will determine
 the scope of service to offer. What is the primary purpose for the
 directory service? A company may find it desirable to do away with a
 paper directory while simultaneously providing the current directory
 information. The directory may be for internal use only or expanded
 to any users with Internet access. Will the customer use the

Jennings Informational [Page 14] RFC 1943 Building an X.500 Directory Service in the US May 1996

 directory for e-mail address only or is other locational information
 such as postal address and telephone number a requirement?
 The directory may provide information to electronic customers such as
 distributed computing applications as well. In this case, the data
 must be provided in machine readable format.
 Will the customers extend across country boundaries? Information may
 be considered private by one country and not by another. It is
 necessary to be aware of the legalities and restrictions for the
 locality using the data.  Some counties have published a Code of
 Conduct with the IETF, explicitly stating the legal restrictions on
 directory and list data. Check the archives to determine if the
 country with whom information will be shared has presented such
 information.

6.4 What are the contents of the Directory?

 The information presented in the directory is tightly coupled with
 the purpose. If the purpose is to provide addressing information for
 individuals, then customary information would include: Name, address,
 phone, e-mail address, facsimile number, pager, etc. If the use of
 the directory is to facilitate electronic mail routing then the
 destination mail address needs to be included for each user. No other
 information should be presented in the directory if it is not
 directly related to the purpose.
 If the directory is internal only, it may be desirable to include the
 registrants title as well. Remember that information available on the
 Internet is generally open to anyone who wants to access it.
 Individuals wishing to target a specific market may access
 directories to create customer mailing lists.
 The structure or schema of the X.500 Directory must be an initial
 consideration. Will the hierarchy follow the company structure or is
 a different approach more practical? How many entries will there be
 in the directory five or 50,000? A complex hierarchyfor thousands of
 users may affect the efficiency of queries.

6.5 What are the rights of the individuals?

 The subjects included in the directory shall have well defined
 rights.  These may be mandated by company policy, legal restrictions,
 and the ultimate use of the directory. For a basic Internet White
 Pages Service these rights may include:

Jennings Informational [Page 15] RFC 1943 Building an X.500 Directory Service in the US May 1996

      1. the option of inclusion in the directory
      2. the right of access to the information
      3. the right to have inaccurate entries corrected
 The terms and conditions for employees of an organization may affect
 these rights. On becoming an employee of any organization, an
 individual inevitably agrees to forego certain personal privacies and
 to accept restrictions.
 Every organization should develop and publish the "rights" that can
 be expected by the list registrants.

6.6 Data Integrity

 Information that needs to be included in the directory may come from
 various sources. Demographic information may originate from the human
 resources department. Electronic mail addresses may be provided by
 the computer network department. To guarantee data integrity, it is
 advised that the data be identified and maintained as corporate
 information.
 The required timeliness of the data is unique for each DSA. Updates
 to the data may be a frequent as once a day or once a month. Updates
 to the data must be provided on a regular basis. In cases where data
 is time sensitive, an attribute should be included to display the
 most recent maintenance date.
 A regular check for data accuracy should be included in the directory
 administration. Faulty information may put an organization in breach
 of any data protection laws and possibly render the company as
 unreliable.

6.7 Data Security

 Securing networked information resources is inherently complex.
 Attempts must be made to preserve the security of the data. These may
 include access control lists (ACLs), limiting the number or responses
 allowed to queries, or internal/external access to the directory.
 The 1993 recommendations have added a complex access control model
 that is designed to tightly restrict the access that users may have
 to the information in the Directory. Local protection is configured
 by the implementor. A secure X.500 Directory should provide tools to
 protect against destruction, falsification, and loss of data.
 There is not a tool yet that will protect against the misuse of data.
 There are flags and limits that can be set from within the
 application that will serve somewhat as a barrier to such unwanted

Jennings Informational [Page 16] RFC 1943 Building an X.500 Directory Service in the US May 1996

 use. Any restrictions however, also will affect the legitimate users.
 One suggestion is to post a notice of illegitimate use within each
 entry. This of course will only serve as a deterrent and as an asset
 should legal action be required.
 Again, caution must be taken when transferring data between country
 and state borders. In the US data regulations differ from state to
 state.

6.8 Data Administration

 The decentralized nature of the X.500 Directory service means that
 each organization has complete control over the data. As part of a
 global service however, it is important that the operation of the DSA
 be monitored and maintained in a consistent manner. Authorization
 must be given to the local manager of the information and in some
 cases, the subjects included in the directory may also have
 modification privileges.
 Once the service is running, the importance of guaranteed operation
 can not be overstated. Maintenance of the local Directory will be an
 integral part of normal administrative procedures within the
 organization and must be defined and agreed upon in the initial
 stages of development.

6.9 Conclusion

 Establishing a Directory service within an organization will involve
 a great deal of cooperative effort. It is essential to get commitment
 from the integral parties of an organization at the onset.  This
 includes the technical, legal, and data managements components of the
 organization.  Executive level commitment will make it much easier to
 get the cooperation necessary.
 Operational procedures must be clearly defined, as the inclusion in a
 globally distributed service has wide visibility. Adherence to these
 procedures must be maintained to the highest degree possible as
 misinformation may result in unintentional legal violations and
 unreliable access or data can adversely affect on a companys
 reputation.
 An X.500 Directory can be extremely useful for an organization if it
 operates as designed. It may serve as the "hub" of the information
 routing and the basis for several everyday activities. A successful
 service will be one of the most important tools for communication in
 the computer network environment. For people to make use of the
 service, they must be able to rely on consistent and accurate
 information.

Jennings Informational [Page 17] RFC 1943 Building an X.500 Directory Service in the US May 1996

References

 1.      CCITT Blue Book, Volume VIII - Fascicle VIII.8, November 1988.
 2.      RFC 1632; A Revised Catalog of Available X.500
         Implementations. A. Getchell; ESnet, S.
         Sataluri; AT&T.
 3.      RFC 1274; The COSINE and Internet X.500 Schema. P. Barker &
         S. Kille.
 4.      CCITT Blue Book, Volume VIII - Fascicle VIII - Rec. X.509,
         November 1988.
 5.      RFC 1295; User Bill of Rights for entries and listing in the
         Public Directory. Networking Working Group; IETF, January
         1992.
 6.      STD 35, RFC 1355; Privacy and Accuracy Issues in Network
         Information Center Databases. Curran, Marine, August 1992.
 7.      RFC 1006, ISO Transport Class 2 Non-use of Explicit Flow
         Control over TCP RFC 1006 extension. Y. Pouffary, June 1995.
 8.      Colin Robbins, NEXOR Ltd., Nottingham, London.
         c.robbins@nexor.co.uk
 9.      InterNIC; Collaborative effort of AT&T and
         Network Solutions; info@internic.net
 10.     ESnet; Managed and funded by the US Department of Energys
         Energy Research Office in Scientific Computing (DOE/ER/OSC).
 11.     RFC 1777; Lightweight Directory Access Protocol, W. Yeong,
         T. Howes, S. Kille, March 1995.
 12.     Building a Directory Service, Final Report test phase SURFnet
         X.500 pilot project, June 1995.
 13.     The X.500 Directory Services: a discussion of the concerns
         raised by the existence of a global Directory, Julia M. Hill,
         Vol.2/No.1 Electronic Networking, Spring 1992.
 14.     Directory Services and Privacy Issues, E. Jeunik and E.
         Huizer.

Jennings Informational [Page 18] RFC 1943 Building an X.500 Directory Service in the US May 1996

 15.     The Little Black Book; Mail Bonding with OSI Directory
         Services, Marshall T. Rose, Simon & Schuster Company,
         1992.
 16.     NYSERNet White Pages Pilot Project: Status Report; NYSERNet
         Technical Report #89-12-31-1, Marshall T. Rose, December 1989.
 17.     RFC 1798, Connection-less Lightweight Directory Access
         Protocol, A. Young, June 1995.
 18.     RFC 1781; Using the OSI Directory to Achieve User Friendly
         Naming, S. Kille, March 1995.
 19.     draft-ietf-pds-iwps-design-spec-01.txt, Tony Genovese;
         Microsoft, Work in Progress, July 1995.
 20.     draft-ietf-ids-privacy-00.txt, B. Jennings; Sandia National
         Laboratories, S. Sataluri; AT&T, Work in Progress, November
         1994.

Glossary

 ACL     Access Control List; a mechanism to restrict access to data
         stored in an X.500 Directory Service
 Attribute       A collection of attributes belong to an entry in the
                 Directory Service, and contain information belonging
                 to that entry.
 c=      countryName; Object class definition, specifies a country.
         When used as part of the directory name, it identifies the
         country in which the named object is physically located.
 cn=     commonName; Attribute defining common name for individuals
         included in a directory. In 1988 standards can be up to 64
         characters.
 CCITT   The International Telegraph and Telephone Consultative
         Committee.
 DAP     Directory Access Protocol; the protocol between a DUA and a
         DSA.
 DIB     Directory Information Base; a collection of information
         objects in the Directory.
 DIT     Directory Information Tree; the hierarchy of the distributed
         database that makes up an X.500 service.

Jennings Informational [Page 19] RFC 1943 Building an X.500 Directory Service in the US May 1996

 DSA     Directory System Agent; an application that offers the
         Directory service, this is the database for the Directory.
 DUA     Directory User Agent; an application that facilitates User
         access to a DSA.
 E-Mail  Electronic Mail.  Entry A Directory Service contains entries
         on people, organizations, countries, etc. Entries belong to a
         certain class, and information on entries is stored in
         attributes.
 ESnet   Energy Sciences Network; nationwide computer data
         communications network.
 GUI     Graphical User Interface.
 IETF    Internet Engineering Task Force; an internationally
         represented task force charged with solving the short-term
         needs of the Internet
 Internet        A collection of connected networks, international,
                 running the Internet suite of protocols.
 InterNIC        Directory of Directories, a collaborative project
                 between AT&T, and Network Solutions, Inc.
 IP      Internet Protocol; the network protocol offering a
         conectionless-mode network service in the Internet suite of
         protocols.
 ISODE   ISO Development Environment, a research tool developed to
         study the upper-layers of OSI and deploy network applications
         according to the ISO OSI standards and ITU X series of
         recommendations.
 ITU     International Telecommunication Union; formerly the CCITT.
 LDAP    Lightweight Directory Access Protocol, an Internet Standard
         for a lightweight version of DAP running over TCP/IP.
 Object  Entries in a Directory Service belong to an Object Class to
         Class indicate the type and characteristic; e.g. Object Class
         "person".
 OSI     Open Standards Interconnection, An international
         standardization program, facilitated by ISO and ITU to develop
         standards for data networking.

Jennings Informational [Page 20] RFC 1943 Building an X.500 Directory Service in the US May 1996

 o=      organization; An attribute defining the company or
         organization that the person works for.
 ou=     organizational unit; An attribute found under organization.
         Denotes the department, division, or other such sub-unit of
         the organization that the person works in.
 PEM     Privacy Enhanced Mail; and Internet Standard for sending
         secure Electronic mail.
 PSI     Performance Systems International, Inc.; operator of the
         Internet White Pages Project
 QUIPU   X.500 Directory implementation developed by Colin Robbins
         while at the University College of London.
 RDN     Relative Distinguished Name; a unique identifier for each list
         subject, defined by the hierarchy of the DSA.
 RFC     Request For Comments; Internet series publications
 sn=     surname; Attribute defining the surname of the person in the
         directory.
 TCP/IP  Transmission Control Protocol and Internet Protocol; two
         internet protocols.
 White-Pages     Electronic directory, accessible via Internet suite of
                 protocols.
 Whois   An Internet standard protocol.
 Whois++ An Internet Directory Services protocol; a possible
         alternative for X.500 WPS
 White Pages Service a Directory Service that contains information on
                     people and organizations.
 X.500   A series of recommendations as defined by the ITU, that
         specify a Directory Services protocol.

Jennings Informational [Page 21] RFC 1943 Building an X.500 Directory Service in the US May 1996

9.0 Security Considerations

 Security issues are not discussed in this memo.

Author's Address

 Barbara Jennings
 Sandia National Laboratories
 Scientific Computing Systems
 P.O. Box 5800
 M/S 0807
 Albuquerque, NM  87106
 USA
 Phone:  505-845-8554
 Fax:    505-844-2067
 EMail:  jennings@sandia.gov

Jennings Informational [Page 22]

/data/webs/external/dokuwiki/data/pages/rfc/rfc1943.txt · Last modified: 1996/05/13 18:17 by 127.0.0.1

Donate Powered by PHP Valid HTML5 Valid CSS Driven by DokuWiki