IT training understanding and deploying ldap directory services

Understanding and Deploying LDAP Directory Services
By Timothy A. Howes,, Mark C. Smith, Gordon S. Good

•

Table of
Contents

Publisher:
Pub Date:
ISBN:
Pages:
Slots:

New Riders Publishing
December 23, 1998
1-57870-070-1
880
2

• Index

Copyright
About the Authors
About the Technical Reviewers
Acknowledgments
Preface
The Book's Organization
The Book's Audience
Contacting Us
Part I: An Introduction to Directory Services and LDAP

Chapter 1. Directory Services Overview
What Is a Directory?
What Can a Directory Do for You?
What a Directory Is Not
Directory Services Overview Checklist
Further Reading
Looking Ahead
Chapter 2. A Brief History of Directories
Prehistory and Early Electronic Directories
Application-Specific and Special-Purpose Directories
Network Operating System Directories
General-Purpose, Standards-Based Directories
Directory Services Future
Conclusion
Directory Services Time Line
Further Reading
Looking Ahead
Chapter 3. An Introduction to LDAP
What Is LDAP?
The LDAP Models
LDAP APIs
LDIF
LDAP and Internationalization
LDAP Overview Checklist
Further Reading
Looking Ahead


Part II: Designing Your Directory Service
Chapter 4. Directory Road Map

The Directory Life Cycle
Directory Design Checklist
Further Reading
Looking Ahead
Chapter 5. Defining Your Directory Needs
An Overview of the Directory Needs Definition Process
Analyzing Your Environment
Determining and Prioritizing Application Needs
Determining and Prioritizing Users' Needs and Expectations
Determining and Prioritizing Deployment Constraints
Determining and Prioritizing Other Environmental Constraints
Choosing an Overall Directory Design and Deployment Approach
Setting Goals and Milestones
Defining Your Directory Needs Checklist
Further Reading
Looking Ahead
Chapter 6. Data Design
Data Design Overview
Common Data-Related Problems
Creating a Data Policy Statement
Identifying Which Data Elements You Need
General Characteristics of Data Elements
Sources for Data
Maintaining Good Relationships with Other Data Sources
Data Design Checklist
Further Reading
Looking Ahead
Chapter 7. Schema Design
The Purpose of a Schema
Elements of LDAP Schemas

Directory Schema Formats
The Schema Checking Process
Schema Design Overview
Sources for Predefined Schemas
Defining New Schema Elements
Documenting and Publishing Your Schemas
Schema Maintenance and Evolution
Schema Design Checklist
Further Reading
Looking Ahead
Chapter 8. Namespace Design
The Structure of a Namespace
The Purposes of a Namespace
Analyzing Your Namespace Needs
Examples of Namespaces


Namespace Design Checklist
Further Reading
Looking Ahead
Chapter 9. Topology Design
Directory Topology Overview
Gluing the Directory Together: Knowledge References
Authentication in a Distributed Directory
Designing Your Directory Server Topology
Topology Design Checklist
Further Reading
Looking Ahead
Chapter 10. Replication Design
Why Replicate?

Replication Concepts
Advanced Features
Designing Your Directory Replication System
Replication Checklist
Further Reading
Looking Ahead
Chapter 11. Privacy and Security Design
Security Guidelines
The Purpose of Security
Security Threats
Security Tools
Analyzing Your Security and Privacy Needs
Designing for Security
Further Reading
Looking Ahead

Part III: Deploying Your Directory Service
Chapter 12. Choosing Directory Products
Making the Right Product Choice
Categories of Directory Software
Evaluation Criteria for Directory Software
Reaching a Decision
Directory Software Options
Choosing Directory Products Checklist
Further Reading
Looking Ahead
Chapter 13. Piloting Your Directory Service
Pre-pilot Testing
A Piloting Road Map
Piloting Checklist

Looking Ahead
Chapter 14. Analyzing and Reducing Costs
The Politics of Costs


Reducing Costs
Design, Piloting, and Deployment Costs
Ongoing Costs of Providing Your Directory Service
Analyzing and Reducing Costs Checklist
Further Reading
Looking Ahead
Chapter 15. Going Production
Creating a Plan for Going Production
Advice for Going Production
Executing Your Plan
Going Production Checklist
Looking Ahead

Part IV: Maintaining Your Directory Service
Chapter 16. Backups and Disaster Recovery
Backup and Restore Procedures
Disaster Planning and Recovery
Directory-Specific Issues in Disaster Recovery
Summary
Backups and Disaster Recovery Checklist
Further Reading
Looking Ahead
Chapter 17. Maintaining Data
The Importance of Data Maintenance
The Data Maintenance Policy

Handling New Data Sources
Handling Exceptions
Checking Data Quality
Data Maintenance Checklist
Further Reading
Looking Ahead
Chapter 18. Monitoring
An Introduction to Monitoring
Selecting and Developing Monitoring Tools
Proactive Monitoring
Notification Techniques
Taking Action
A Sample Directory Monitoring Utility
Monitoring Checklist
Further Reading
Looking Ahead
Chapter 19. Troubleshooting
Discovering Problems
Types of Problems
Troubleshooting and Resolving Problems
Troubleshooting Checklist
Looking Ahead


Part V: Leveraging Your Directory Service
Chapter 20. Developing New Applications
Reasons to Develop Directory-Enabled Applications
Common Ways Applications Use Directories
Tools for Developing LDAP Applications
Advice for LDAP Application Developers

Example 1: A Password-Resetting Utility
Example 2: An Employee Time-Off Request Web Application
Developing New Applications Checklist
Further Reading
Looking Ahead
Chapter 21. Directory-Enabling ExistingApplications
Reasons to Directory-Enable Existing Applications
Advice for Directory-Enabling Existing Applications
Example 1: A Directory-Enabled fingerService
Example 2: Adding LDAP Lookup to an Email Client
Directory-Enabling Existing Applications Checklist
Further Reading
Looking Ahead
Chapter 22. Directory Coexistence
Why Is Coexistence Important?
Determining Your Requirements
Coexistence Techniques
Privacy and Security Considerations
Example 1: One-Way Synchronization with Join
Example 2: A Virtual Directory
Directory Coexistence Checklist
Further Reading
Looking Ahead

Part VI: Case Studies
Chapter 23. Case Study: Netscape Communications Corporation
An Overview of the Organization
Directory Drivers
Directory Service Design
Directory Service Deployment

Directory Service Maintenance
Leveraging the Directory Service
Summary and Lessons Learned
Further Reading
Looking Ahead
Chapter 24. Case Study: A Large University
An Overview of the Organization
Directory Drivers
Directory Service Design
Deployment


Maintenance
Leveraging the Directory Service
Applications
Directory Deployment Impact
Summary and Lessons Learned
Looking Ahead
Chapter 25. Case Study: A Large Multinational Enterprise
An Overview of the Organization
Directory Drivers
Directory Service Design
Deployment
Maintenance
Leveraging the Directory Service
Summary and Lessons Learned
Further Reading
Looking Ahead
Chapter 26. Case Study: An Enterprise with an Extranet
An Overview of the Organization

Directory Drivers
Directory Service Design
Deployment
Maintenance
Leveraging the Directory Service
Summary and Lessons Learned
Further Reading

Index



Copyright
Copyright Information
Copyright © 1999 by Netscape Communications Corporation
FIRST EDITION
All rights reserved. No part of this book may be reproduced or transmitted in any
form or by any means, electronic or mechanical, including photocopying,
recording, or by any information storage and retrieval system, without written
permission from the publisher, except for the inclusion of brief quotations in a
review.
Library of Congress Catalog Card Number: 98-84230
2001 00 4
Interpretation of the printing code: The rightmost double-digit number is the year
of the book's printing; the rightmost single-digit, the number of the book's
printing. For example, the printing code 98-1 shows that the first printing of the
book occurred in 1998.
Composed in Palatino and MCPdigital by Macmillan Computer Publishing
Printed in the United States of America

Trademark Acknowledgments
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marks have been appropriately capitalized. Macmillan Technical Publishing
cannot attest to the accuracy of this information. Use of a term in this book should
not be regarded as affecting the validity of any trademark or service mark.

Warning and Disclaimer
This book is designed to provide information about LDAP directory services.
Every effort has been made to make this book as complete and as accurate as
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Dedication
For Nancy, whose love and support make it all worthwhile.


—Tim Howes
For my wife, Kathy, who supports me wonderfully in everything I do.
—Mark Smith
For my mother and father, and my brothers, Brian and Kevin.
—Gordon Good


About the Authors
Timothy A. Howes is vice president and chief technology officer of Netscape
Communications Corporation's Server Product Division. He was one of the
original authors of the Internet LDAP directory protocol and remains a driving
force behind its continued evolution. He is cochair of the IETF LDAP Extensions
working group and a member of the Internet Architecture Board. In addition to
being a coauthor of LDAP: Programming Directory-Enabled Applications with
Lightweight Directory Access Protocol, he has written numerous Internet RFCs,
papers, and articles. He received his Ph.D. in computer science and engineering
from the University of Michigan.
Mark C. Smith is a principal engineer and directory architect at Netscape
Communications Corporation, where he is responsible for the technical evolution
of Netscape Directory Server and related products. He was previously a driving
force behind the University of Michigan's LDAP implementation, and a key
designer of the university's directory service. Mark is coauthor of LDAP:
Programming Directory-Enabled Applications with Lightweight Directory Access

Protocol, and has written many RFCs and Internet drafts.
Gordon S. Good is a senior member of the technical staff at Netscape
Communications Corporation, where he leads the directory server replication
development team. Previously, he was instrumental in the development of the
University of Michigan's LDAP implementation and in designing and running the
university's Web and email services. Gordon has also written several Internet
drafts on directories.


About the Technical Reviewers
These reviewers, Leif Hedstrom, Chuck Lever, and Mike SoRelle, contributed
their considerable practical, hands-on expertise to the development process for
Understanding and Deploying LDAP Directory Services. As the book was being
written, these folks reviewed all the material for technical content, organization,
and flow. Their feedback was critical to ensuring that Understanding and
Deploying LDAP Directory Servicesfits our readers' need for the highest quality
technical information.
Leif Hedstrom is a principal UNIX architect for Netscape Communications
Corporation, where he is responsible for internal infrastructure and deployment of
UNIX servers and clients, as well as email, directory, and calendar services. He
was the primary architect for Netscape's internal LDAP directory server
environment. He has several years' experience resolving complex email- and
LDAP-related issues, and he developed a large software system to convert
Netscape's information infrastructure to LDAP by integrating with legacy
directory services and traditional databases. Before joining Netscape in 1996, Leif
developed and helped to manage Infoseek Corporation's first HTTP front-end
server for its popular search engine.
Charles Lever is a computer science researcher working on LDAP server
performance on Linux for Netscape Communications Corporation. Previously,
Chuck was the technical lead for teams providing production-quality UNIX and

LDAP directory services to the University of Michigan main campus in Ann
Arbor. In this capacity, he provided technical leadership and strategic
architectural direction for teams supporting LDAP servers and clients, UNIX
systems, electronic mail, and high-performance statistical computation. Before
coming to LDAP and UNIX production work, he helped port Transarc
Corporation's AFS and DFS to IBM mainframe systems and developed operating
system software for MTS, U-M's proprietary mainframe operating system.
Michael SoRelle is a systems operations group leader for MCI
Telecommunications, where he manages a team of engineers in the day-to-day
operation of server and workstation support for the U.S. Postal Service Network
Management Center. He provides support to servers, workstations, and LAN
equipment, and he tests and deploys new applications and equipment throughout
the network. He is responsible for several Microsoft Exchange servers as part of
the MCI InnerMail team—with more than 55,000 employees in the directory. He
is the local contact for the Enterprise Security Task Force, encompassing all
aspects of data security from Web server security to firewalls. Previous to joining
MCI, Michael was a network analyst responsible for enterprise network planning,
design, implementation, and support at Texas Children's Hospital.



Acknowledgments
We'd like to thank our management and the publishing relations department at
Netscape, whose support enabled us to write this book. Specifically, our thanks
go out to Claire Hough, John Paul, Ben Horowitz, David Weiden, Neel Phadnis,
Susan Walton, and Suzanne Anthony.
In addition, we'd like to thank the Netscape IS department for their help in writing
the Netscape case study. Bob Ferguson, Gene Irvine, and especially the incredible
Leif Hedstrom deserve special thanks.
We'd like to thank the people who reviewed parts of this book, including Leif

Hedstrom, Mike SoRelle, Chuck Lever, Kathleen Brade, and Nancy Cartwright.
We'd also like to thank the team at Macmillan Publishing. Kitty Jarrett deserves
special thanks for her professionalism in making the process go so smoothly.
Thanks to Brett Bartow for his guidance and gentle prodding, which kept us
almost on schedule, and to the rest of the Macmillan team.


Preface
In the past three years, LDAP directories have risen from a relatively obscure
offshoot of an equally obscure field to become one of the linchpins of modern
computing on the Internet. Increasingly, LDAP directories are becoming the
nerve center of an organization's computing infrastructure, providing naming,
location, management, security, and other services that have traditionally been
provided by network operating systems. Design and deployment of a successful
LDAP directory service can be complex and challenging, yet until now little
information was available explaining the ins and outs of this important task.
When two of us (Mark and Tim) finished writing a previous book, LDAP:
Programming Directory-Enabled Applications with Lightweight Directory Access
Protocol in early 1997, we soon realized there was another, much bigger piece of
the directory puzzle still to be addressed. The previous book was aimed at
directory application programmers, but nothing similar was available to address
the needs of directory decision makers, designers, and administrators. This book
is aimed at that audience.
Recognizing the size of the task ahead of us and remembering the joys of giving
up evenings and weekends for months at a time to meet deadlines for our first
book, we quickly decided to expand our team. Just as quickly, we decided there
was no one we'd rather share the fun with than our longtime friend and colleague,
Gordon Good. Aside from being the third leg of the LDAP development team at
the University of Michigan (U-M) and now a senior directory developer at
Netscape, Gordon brought a wealth of system administration experience from his

past life as a directory and email administrator and Web master for U-M. With
Gordon on board, the three of us set about writing a book that we only halfjokingly referred to as the "LDAP Bible."


The Book's Organization
This book includes 26 chapters in 6 parts. Part I introduces directories and LDAP.
Parts II through IV each address a different part of the directory life cycle. Part
Vdiscusses how to leverage your directory service once it's up and running.
Finally, Part VIpresents four directory services deployment case studies.
Part I provides a fairly comprehensive introduction to directories and LDAP. For
readers unfamiliar with the topic, this section should bring them up to speed and
provide the background necessary to understand the rest of the book. It also
includes a section on the history of directories for readers interested in how all
this technology came about.
Part II begins to delve into the directory life cycle by covering the first and in
many ways most important phase: design. We cover all aspects of directory
design, from determining your needs, to designing your data sources, schema,
namespace, topology, replication, and finally privacy and security.
Part III covers the next phase in the directory life cycle: deployment. We cover
everything from choosing the right directory products to piloting your service to
going production. We've also included a section about analyzing the cost of your
service and how to help reduce those costs.
Part IV concludes our coverage of the directory life cycle with a look at the
maintenance phase. We cover such topics as backup and disaster recovery,
maintaining data, monitoring your directory system, and troubleshooting
problems when they occur.
Part V talks about how to take advantage of the service you have designed and
deployed. We discuss the benefits and pitfalls of directory-enabling existing
applications, creating new applications that use the directory, and how your
directory can coexist with other data sources.

Part VI closes the book by presenting a number of directory case studies. Some of
the case studies presented are real and some are fictitious, but all are designed to
illustrate the concepts of directory design, deployment, and maintenance in
action.


The Book's Audience
This book is primarily intended for three kinds of readers: decision makers,
designers, and administrators. In addition, anyone who wants to know more about
LDAP or directories in general will find the book useful, as will directory
developers.
Directory decision makers will find this book useful in understanding directories
and the kinds of business problems they help solve. Decision makers will find
Part I useful for explaining the basics of directories. Part VI should also prove
useful by providing some real, or at least realistic, examples of how directories
are used and the benefits they can bring.
Directory designers will find this book useful in defining the design problem and
providing a methodology for producing a comprehensive directory design. The
design methodology is focused on a practical approach to design based on realworld requirements. We highly recommend that designers read the whole book,
with special emphasis on Part II, part IIIand part IV. A good directory design
results in large part from a clear understanding of the other aspects of the
directory life cycle and how the directory will be used.
Directory administrators will find Part IV especially useful. It focuses on the
maintenance phase of the directory life cycle, where administrators spend much
of their lives. We also highly recommend that administrators read the rest of the
book to get an idea of the directory big picture, as well as to understand some of
the directory design decisions that are bound to make their lives either miserable
or enjoyable.
Other interested readers can pick and choose from the sections of the book that
interest them. We encourage all readers to at least skim Part I, to ensure that they

have the background required to benefit from the rest of the book. We've tried to
structure the book so that each chapter stands by itself as much as possible.
Readers should be able to read the chapters covering topics that interest them,
without wading through chapters of less interest. Finally, we think all readers will
find the case studies presented in Part VIinteresting. They give different
perspectives on directories designed to illustrate the trade-offs that different
directory needs imply.


Contacting Us
Finally, if you have comments or suggestions about this book or if you'd like to
tell us about an interesting directory deployment or application you've developed,
we'd like to hear from you. Feel free to drop us a line at the following addresses:
Tim Howes



Mark Smith



Gordon Good



We'll try our best to get back to you, but keep in mind that we all have day jobs!


Part I: An Introduction to Directory
Services and LDAP

1 Directory Services Overview
2 A Brief History of Directories
3 An Introduction to LDAP


Chapter 1. Directory Services Overview
The fact that you have picked up this book and started to read it suggests that you
have some idea what a directory service is and what it can do for you. This
chapter assumes you have an everyday understanding of directories and expands
on that notion to answer three simple but important questions:
●

●

●

What is a directory? In brief, a directory is a specialized database. In this
chapter you'll learn what makes a directory specialized, what separates it
from a traditional database, the defining characteristics of a directory, and
why they are important.
What can a directory do for you? Directories can do many things, and
you probably chose this book with some particular set of problems in mind
that you'd like a directory to help you solve. We'll take you through the
basic uses of a directory, many of which may have already occurred to
you, as well as covering some more-advanced uses that may be new to
you.
What isn't a directory? The answer to this question is sometimes even
more important when defining a successful directory environment than
learning what a directory is. In this chapter you'll learn what separates a
directory from a file system, a Web server, and other things you have

deployed on your network. The distinctions drawn here are crucial to
narrowing the task of designing your directory service.

This chapter aims to answer each of these questions in detail, formalizing the
answers to give you a common understanding of the task before you: designing a
directory service. You'll learn why directories are important, the scope of a
directory solution, and what they can do for you. Armed with this knowledge,
you'll be ready to read the rest of the book, which deals with the details of
understanding, designing, deploying, maintaining, and finally making use of your
very own directory service.
Directory Service Defined
We will use many terms throughout this book that may be new to
you. A directory service is the collection of software, hardware,
processes, policies, and administrative procedures involved in
making the information in your directory available to the users of
your directory. Your directory service includes at least the
following components:
●
●
●

Information contained in the directory
Software servers holding this information
Software clients acting on behalf of users or other entities


●
●

●

●

●

●

accessing this information
The hardware on which these clients and servers run
The supporting software, such as operating systems and
device drivers
The network infrastructure connecting clients to servers and
servers to each other
The policies governing who can access and update the
directory, what can be stored in it, and so on
The procedures by which the directory service is
maintained and monitored
The software used to maintain and monitor the directory
service

As you can see, it's quite a list! Some of these components are
depicted in Figure 1.1. Generally, we will use the term directory as
a synonym for directory service. It's important to keep in mind that
your directory is a sophisticated system of components that work
together to provide a service. Concentrating exclusively on one set
of components without thinking about the others is sure to lead to
trouble.

Figure 1.1. Directory system components.

What Is a Directory?
Most people are familiar with various kinds of directories, whether they realize it
or not. Directories are part of our everyday lives. Everyday examples of directories
we encounter include the phone book and yellow pages, TV Guide, shopping
catalogs, the library card catalog, and others. We refer to these directories as
everyday directories, or sometimes offline directories.
Using these examples as a guide, it's clear that directories help people find things
by describing and organizing the items to be found. Information in such directories
ranges from phone numbers to television shows, from consumer goods to
reference material, and more.
Directories in the computer and networking world are similar in many ways, but
with some important differences. We call these directories online directories.
Online directories differ from offline directories in the following ways:
●
●
●
●

Online directories are dynamic.
Online directories are flexible.
Online directories can be made secure.
Online direc tories can be personalized.

These differences are explored in the sections that follow. It's also important to
understand that there are different kinds of directories. We expand on this notion
more in Chapter 2, "A Brief History of Directories." We'll give a brief
categorization here in order to frame the rest of our discussion. We divide
directories into the following categories:
●

●

●

●

NOS-based directories. Directories such as Novell's NDS, Microsoft's
Active Directory, and Banyan's StreetTalk Directory are based on a
network operating system (NOS). NOS-based directories such as these are
developed specifically to serve the needs of a network operating system.
Application-specific directories. These directories come bundled with or
embedded into an application. Examples are the Lotus Notes name and
address book, the Microsoft Exchange directory, and Novell's GroupWise
directory.
Purpose-specific directories . These directories are not tied to an
application, but are designed for a narrowly defined purpose and are not
extensible. An example is the Internet's Domain Name System (DNS).
General-purpose, standards-based directories. These directories are
developed to serve the needs of a wide variety of applications. Examples
include the LDAP directories we focus on in this book and X.500-based
directories.


In this chapter we will make reference to all four types of directories. Our focus is
squarely on the general-purpose type of directory, however.

Directories Are Dynamic
The everyday directories you are familiar with are relatively static; that is, they do
not change very often. For example, the phone book comes once a year; you have

to call information to get more up-to-date information. A new TV Guide is
produced every week, but still your favorite show is pre-empted without notice
more often than you'd like. The shopping catalogs you receive in the mail are
updated only several times a year, at most; also, they do not contain such useful
information as which items are in stock in which colors and sizes. Why? Because
that information changes so often that by the time the catalog got to you, it would
be out-of-date.
By contrast, online directories have the capacity to be kept much more up-to-date.
This feature is not always used, of course. Directories are usually only as up-todate as their administrators choose to keep them. Sometimes administrative
procedures are put in place to update the directory automatically. Often, online
directories are much better if they are their own ultimate authority for the
information they hold. As soon as information changes, it can be updated in the
directory and made available to users.
It's easy to see how this online update capability can be used to make directories
more accurate, resulting in a more useful directory. This kind of improvement is
incremental. But online updates have the potential to produce more revolutionary
improvements, too. These improvements open the door to brand new directory
applications that have no offline analogy.
For example, consider a directory that contains up-to-date information on who's
employed at your organization. Such a directory could be consulted by an
automated card reader to authorize access to buildings and rooms at your
company. In this case, access could be revoked easily and instantly, simply by
making a change to the directory.
As another example, consider a directory containing location information that is
updated as you move from office to office, from hotel room to hotel room, and to
other locations. This directory could be consulted to route your phone calls, faxes,
and messages to you wherever you are. Traditional paper directories could never
be used for such a purpose. However, the very nature of this application requires
very frequent updates of the information.
This superior update capacity of online directories not only tends to keep

information more up-to-date, it also can be used to distribute the update


responsibility. The closer information is to its source, the more accurate and
timely the information is likely to be. There are at least three reasons for this:
●
●

●

The source of the information is, by definition, the most accurate.
Extra delay and opportunity for error between the source and the directory
are eliminated if the source makes the update itself.
Depending on the information and the application, the source is likely to be
the party most motivated to maintain the information correctly.

To illustrate, consider the location directory example described previously. The
source is the user (you) and the information is your current location. Who knows
better than you where you are? (One would hope you know that best!) Which is
the more accurate path for an update to be received on: directly from you or from
your administrative assistant (your typing skills not with- standing)? Suppose the
update came from a directory administrator typing in information reported by your
assistant relayed from you? At each step, opportunity for error is introduced, and
the accuracy is further decreased. Finally, who is most motivated to have accurate
information about you in the directory? Again, it is likely to be you, the source,
because you do not get your phone calls, faxes, and mail unless the information is
accurate. Of course, this example assumes that you are responsible enough to want
the information to be accurate and that you have the tools and expertise to make it
happen.

Directories Are Flexible
Another important difference between static, everyday directories and online
directories is that online directories offer far greater flexibility. This flexibility has
two aspects:
●
●

Online directories are flexible in the types of information they can store.
Online directories are flexible in the ways that information can be
organized and searched.

Flexible Content
Offline directories are static in terms of their content. By that we mean that offline
directories contain a very restricted and seldom extended set of information. For
example, if you wanted to know something beyond the phone number, address,
and name information provided by your phone book, you are probably out of luck.
But there is a whole host of other useful information you might like to have. Fax
number, mobile phone number, pager number, email address, even a picture or
short biographical sketch, to name a few, are all items in the same category as the
traditional phone information. But these items are seldom, if ever, included.