Red Hat 8.1 Quick reference guide

Red Hat Directory
Server 8.1
Deployment Guide
Ella Deon Lackey
Publication date: April 28, 2009, updated on September 9, 2009

Deployment Guide
Deployment Guide
Author Ella Deon Lackey
Copyright © 2009 Red Hat, Inc.
Copyright © 2009 Red Hat, Inc.. This material may only be distributed subject to the terms and
conditions set forth in the Open Publication License, V1.0 or later (the latest version of the OPL is
presently available at http://www.opencontent.org/openpub/).
Red Hat and the Red Hat "Shadow Man" logo are registered trademarks of Red Hat, Inc. in the United
States and other countries.
All other trademarks referenced herein are the property of their respective owners.
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This manual covers the basic considerations that should be addressed before deploying Red Hat
Directory Server. The decisions made during this phase can have a significant and lasting affect
on the effectiveness, efficiency, and scalability of your Directory Server. You should have a good
understanding of your Directory Server requirements before moving on to the installation phase.

iii
Preface v
1. Directory Server Overview ............................................................................................... v
2. Examples and Formatting ................................................................................................ v
3. Additional Reading ......................................................................................................... vii
4. Giving Feedback ........................................................................................................... viii
5. Documentation History .................................................................................................. viii
1. Introduction to Directory Services 1
1.1. About Directory Services .............................................................................................. 1
1.2. Introduction to Directory Server ..................................................................................... 2
1.3. Directory Server Data Storage ...................................................................................... 5
1.4. Directory Design Overview ............................................................................................ 6
1.5. Other General Directory Resources ............................................................................... 8
2. Planning the Directory Data 9
2.1. Introduction to Directory Data ....................................................................................... 9
2.2. Defining Directory Needs ............................................................................................ 10
2.3. Performing a Site Survey ............................................................................................ 10
2.4. Documenting the Site Survey ...................................................................................... 17
2.5. Repeating the Site Survey .......................................................................................... 18
3. Designing the Directory Schema 19
3.1. Schema Design Process Overview .............................................................................. 19
3.2. Standard Schema ....................................................................................................... 19
3.3. Mapping the Data to the Default Schema .................................................................... 22
3.4. Customizing the Schema ............................................................................................ 24
3.5. Maintaining Consistent Schema .................................................................................. 30
3.6. Other Schema Resources ........................................................................................... 31
4. Designing the Directory Tree 33
4.1. Introduction to the Directory Tree ................................................................................ 33
4.2. Designing the Directory Tree ....................................................................................... 33
4.3. Grouping Directory Entries .......................................................................................... 44
4.4. Virtual Directory Information Tree Views ...................................................................... 47
4.5. Directory Tree Design Examples ................................................................................. 53
4.6. Other Directory Tree Resources .................................................................................. 55
5. Designing the Directory Topology 57
5.1. Topology Overview ..................................................................................................... 57
5.2. Distributing the Directory Data ..................................................................................... 57
5.3. About Knowledge References ..................................................................................... 61
5.4. Using Indexes to Improve Database Performance ........................................................ 71
6. Designing the Replication Process 75
6.1. Introduction to Replication ........................................................................................... 75
6.2. Common Replication Scenarios ................................................................................... 78
6.3. Defining a Replication Strategy ................................................................................... 86
6.4. Using Replication with Other Directory Server Features ................................................ 95
7. Designing Synchronization 99
7.1. Windows Synchronization Overview ............................................................................ 99
7.2. Planning Windows Synchronization ........................................................................... 100
7.3. Schema Elements Synchronized Between Active Directory and Directory Server ........... 105
8. Designing a Secure Directory 111

Deployment Guide
iv
8.1. About Security Threats ............................................................................................. 111
8.2. Analyzing Security Needs ......................................................................................... 112
8.3. Overview of Security Methods ................................................................................... 114
8.4. Selecting Appropriate Authentication Methods ............................................................ 115
8.5. Preventing Authentication by Account Deactivation ..................................................... 118
8.6. Designing a Password Policy .................................................................................... 118
8.7. Designing Access Control ......................................................................................... 125
8.8. Database Encryption ................................................................................................. 133
8.9. Securing Server to Server Connections ..................................................................... 134
8.10. Other Security Resources ....................................................................................... 134
9. Directory Design Examples 137
9.1. Design Example: A Local Enterprise .......................................................................... 137
9.2. Design Example: A Multinational Enterprise and Its Extranet ....................................... 143

v
Preface
The Red Hat Directory Server Deployment Guide provides a solid foundation on the on concepts
and configuration options for planning an effective directory service. The information provided here is
intended for both designers and administrators.
1. Directory Server Overview
Red Hat Directory Server provides the following key features:
• Multi-master replication — Provides a highly available directory service for both read and write
operations. Multi-master replication can be combined with simple and cascading replication
scenarios to provide a highly flexible and scalable replication environment.
• Chaining and referrals — Increases the power of the directory by storing a complete logical view
of the directory on a single server while maintaining data on a large number of Directory Servers
transparently for clients.
• Roles and classes of service — Provides a flexible mechanism for grouping and sharing attributes
between entries dynamically.
• Efficient access control mechanisms — Provides support for macros that dramatically reduce the
number of access control statements used in the directory and increase the scalability of access
control evaluation.
• Resource-limits by bind DN — Grants the power to control the amount of server resources allocated
to search operations based on the bind DN of the client.
• Multiple databases — Provides a simple way of breaking down the directory data to simplify the
implementation of replication and chaining in the directory service.
• Password policy and account lockout — Defines a set of rules that govern how passwords and user
accounts are managed in the Directory Server.
• TLS and SSL — Provides secure authentication and communication over the network, using the
Mozilla Network Security Services (NSS) libraries for cryptography.
The major components of Directory Server include the following:
• An LDAP server — The LDAP v3-compliant network daemon.
• Directory Server Console — A graphical management console that dramatically reduces the effort of
setting up and maintaining the directory service.
• SNMP agent — Can monitor the Directory Server using the Simple Network Management Protocol
(SNMP).
2. Examples and Formatting
Each of the examples used in this guide, such as file locations and commands, have certain defined
conventions.

Preface
vi
2.1. Command and File Examples
All of the examples for Red Hat Directory Server commands, file locations, and other usage are given
for Red Hat Enterprise Linux 5 (32-bit) systems. Be certain to use the appropriate commands and files
for your platform.
To start the Red Hat Directory Server:
service dirsv start
Example 1. Example Command
2.2. Tool Locations
The tools for Red Hat Directory Server are located in the /usr/bin and the /usr/sbin directories.
These tools can be run from any location without specifying the tool location.
2.3. LDAP Locations
There is another important consideration with the Red Hat Directory Server tools. The LDAP tools
referenced in this guide are Mozilla LDAP, installed with Red Hat Directory Server in the /usr/lib/
mozldap directory on Red Hat Enterprise Linux 5 (32-bit) (or /usr/lib64/mozldap for 64-bit
systems).
However, Red Hat Enterprise Linux systems also include LDAP tools from OpenLDAP in the /usr/
bin directory. It is possible to use the OpenLDAP commands as shown in the examples, but you must
use the -x argument to disable SASL, which OpenLDAP tools use by default.
2.4. Text Formatting and Styles
Certain words are represented in different fonts, styles, and weights. Different character formatting is
used to indicate the function or purpose of the phrase being highlighted.
Formatting Style Purpose
Monospace font Monospace is used for commands, package
names, files and directory paths, and any text
displayed in a prompt.
Monospace
with a
background
This type of formatting is used for anything
entered or returned in a command prompt.
Italicized text Any text which is italicized is a variable, such
as instance_name or hostname. Occasionally,
this is also used to emphasize a new term or
other phrase.
Bolded text Most phrases which are in bold are application
names, such as Cygwin, or are fields or
options in a user interface, such as a User
Name Here: field or Save button.
Other formatting styles draw attention to important text.

Additional Reading
vii
NOTE
A note provides additional information that can help illustrate the behavior of the system or
provide more detail for a specific issue.
IMPORTANT
Important information is necessary, but possibly unexpected, such as a configuration
change that will not persist after a reboot.
WARNING
A warning indicates potential data loss, as may happen when tuning hardware for
maximum performance.
3. Additional Reading
The Directory Server Administrator's Guide describes how to set up, configure, and administer Red
Hat Directory Server and its contents. this manual does not describe many of the basic directory and
architectural concepts that you need to deploy, install, and administer a directory service successfully.
Those concepts are contained in the Red Hat Directory Server Deployment Guide. You should read
that book before continuing with this manual.
When you are familiar with Directory Server concepts and have done some preliminary planning for
your directory service, install the Directory Server. The instructions for installing the various Directory
Server components are contained in the Red Hat Directory Server Installation Guide. Many of the
scripts and commands used to install and administer the Directory Server are explained in detail in the
Red Hat Directory Server Configuration, Command, and File Reference.
Also, Managing Servers with Red Hat Console contains general background information on how to
use the Red Hat Console. You should read and understand the concepts in that book before you
attempt to administer Directory Server.
The document set for Directory Server contains the following guides:
•Red Hat Directory Server Release Notes contain important information on new features, fixed bugs,
known issues and workarounds, and other important deployment information for this specific version
of Directory Server.
•Red Hat Directory Server Deployment Guide provides an overview for planning a deployment of the
Directory Server.
•Red Hat Directory Server Administrator's Guide contains procedures for the day-to-day maintenance
of the directory service. Includes information on configuring server-side plug-ins.
•Red Hat Directory Server Configuration, Command, and File Reference provides reference
information on the command-line scripts, configuration attributes, and log files shipped with
Directory Server.
•Red Hat Directory Server Installation Guide contains procedures for installing your Directory Server
as well as procedures for migrating from a previous installation of Directory Server.

Preface
viii
•Red Hat Directory Server Schema Reference provides reference information about the Directory
Server schema.
•Red Hat Directory Server Plug-in Programmer's Guide describes how to write server plug-ins in
order to customize and extend the capabilities of Directory Server.
•Using Red Hat Console gives an overview of the primary user interface and how it interacts with
the Directory Server and Administration Server, as well as how to perform basic management tasks
through the main Console window.
•Using the Admin Server describes the different tasks and tools associated with the Administration
Server and how to use the Administration Server with the Configuration and User Directory Server
instances.
For the latest information about Directory Server, including current release notes, complete product
documentation, technical notes, and deployment information, see the Red Hat Directory Server
documentation site at http://www.redhat.com/docs/manuals/dir-server/.
4. Giving Feedback
If there is any error in this Deployment Guide or there is any way to improve the documentation,
please let us know. Bugs can be filed against the documentation for Red Hat Directory Server through
Bugzilla, http://bugzilla.redhat.com/bugzilla. Make the bug report as specific as possible, so we can be
more effective in correcting any issues:
• Select the Red Hat Directory Server product.
• Set the component to Doc - deployment-guide.
• Set the version number to 8.1.
• For errors, give the page number (for the PDF) or URL (for the HTML), and give a succinct
description of the problem, such as incorrect procedure or typo.
For enhancements, put in what information needs to be added and why.
• Give a clear title for the bug. For example, "Incorrect command example for setup
script options" is better than "Bad example".
We appreciate receiving any feedback — requests for new sections, corrections, improvements,
enhancements, even new ways of delivering the documentation or new styles of docs. You are
welcome to contact Red Hat Content Services directly at [email protected]1.
5. Documentation History
Revision 8.1.2 September 9, 2009 Ella Deon Lackey
Removing any references to the Directory Server Gateway or Org Chart.
Revision 8.1.1 April 28, 2009 Ella Deon Lackey [email protected]
1 mailto:[email protected]

Documentation History
ix
Spellchecking and correcting typo, per Bugzilla #516693.
Revision 8.1.0 April 28, 2009 Ella Deon Lackey [email protected]
Initial draft for version 8.1.

x

Chapter 1.
1
Introduction to Directory Services
Red Hat Directory Server provides a centralized directory service for an intranet, network, and extranet
information. Directory Server integrates with existing systems and acts as a centralized repository for
the consolidation of employee, customer, supplier, and partner information. Directory Server can even
be extended to manage user profiles, preferences, and authentication.
This chapter describes the basic ideas and concepts for understanding what a directory service does
to help begin designing the directory service.
1.1. About Directory Services
The term directory service refers to the collection of software, hardware, and processes that store
information about an enterprise, subscribers, or both, and make that information available to users. A
directory service consists of at least one instance of Directory Server and at least one directory client
program. Client programs can access names, phone numbers, addresses, and other data stored in the
directory service.
An example of a directory service is a domain name system (DNS) server. A DNS server maps
computer hostnames to IP addresses. Thus, all of the computing resources (hosts) become clients of
the DNS server. Mapping hostnames allows users of computing resources to easily locate computers
on a network by remembering hostnames rather than IP addresses. A limitation of a DNS server is
that it stores only two types of information: names and IP addresses. A true directory service stores
virtually unlimited types of information.
Directory Server stores all user and network information in a single, network-accessible repository.
Many kinds of different information can be stored in the Directory Server:
• Physical device information, such as data about the printers in an organization, such as location,
color or black and white, manufacturer, date of purchase, and serial number.
• Public employee information, such as name, email address, and department.
• Private employee information, such as salary, government identification numbers, home addresses,
phone numbers, and pay grade.
• Contract or account information, such as the name of a client, final delivery date, bidding
information, contract numbers, and project dates.
Directory Server serves the needs of a wide variety of applications. It also provides a standard
protocol and application programming interfaces (APIs) to access the information it contains.
1.1.1. About Global Directory Services
Directory Server provides global directory services, which means that it provides information to a wide
variety of applications. Rather than attempting to unify proprietary databases bundled with different
applications, which is an administrative burden, Directory Server is a single solution to manage the
same information.
For example, a company is running three different proprietary email systems, each with its own
proprietary directory service. If users change their passwords in one directory, the changes are not
automatically replicated in the others. Managing multiple instances of the same information results in

Chapter 1. Introduction to Directory Services
2
increased hardware and personnel costs; the increased maintenance overhead is referred to as the n
+1 directory problem.
A global directory service solves the n+1 directory problem by providing a single, centralized
repository of directory information that any application can access. However, giving a wide variety
of applications access to the directory service requires a network-based means of communicating
between the applications and the directory service. Directory Server uses LDAP for applications to
access to its global directory service.
1.1.2. About LDAP
LDAP provides a common language that client applications and servers use to communicate with one
another. LDAP is a "lightweight" version of the Directory Access Protocol (DAP) described by the ISO
X.500 standard. DAP gives any application access to the directory through an extensible and robust
information framework but at a high administrative cost. DAP uses a communications layer that is not
the Internet standard protocol and has complex directory-naming conventions.
LDAP preserves the best features of DAP while reducing administrative costs. LDAP uses an open
directory access protocol running over TCP/IP and simplified encoding methods. It retains the
data model and can support millions of entries for a modest investment in hardware and network
infrastructure.
1.2. Introduction to Directory Server
Red Hat Directory Server includes the directory itself, the server-side software that implements the
LDAP protocol, and a client-side graphical user interface that allows end-users to search and change
entries in the directory. Other LDAP clients, both third-party programs and custom programs written
using the LDAP client SDK, both the Mozilla LDAP SDK and the OpenLDAP SDK.
Without adding other LDAP client programs, Directory Server can provide the foundation for an
intranet or extranet. Every Directory Server and compatible server applications use the directory as
a central repository for shared server information, such as employee, customer, supplier, and partner
data.
Directory Server can manage user authentication, create access control, set up user preferences, and
centralize user management. In hosted environments, partners, customers, and suppliers can manage
their own portions of the directory, reducing administrative costs.
When Directory Server is installed and set up, the following components are installed:
• The core Directory Server LDAP server, the LDAP v3-compliant network daemon (ns-slapd) and
all of the associated plug-ins, command-line tools for managing the server and its databases, and
its configuration and schema files. For more information about the command-line tools, see the
Directory Server Configuration, Command, and File Reference.
• Administration Server, a web server which controls the different portals that access the LDAP
server. For more information about the Administration Server, see Using the Admin Server.
• Directory Server Console, a graphical management console that dramatically reduces the effort of
setting up and maintaining the directory service. For more information about the Directory Server
Console, see Using Red Hat Console.

Overview of the Server Frontend
3
• SNMP agent to monitor the Directory Server using the Simple Network Management Protocol
(SNMP). For more information about SNMP monitoring, see the Directory Server Administrator's
Guide.
1.2.1. Overview of the Server Frontend
Directory Server is a multi-threaded application. This means that multiple clients can bind to the server
at the same time over the same network. As directory services grow to include larger numbers of
entries or geographically-dispersed clients, they also include multiple Directory Servers placed in
strategic places around the network.
The server frontend of Directory Server manages communications with directory client programs.
Multiple client programs can communicate with the server using both LDAP over TCP/IP (Internet
traffic protocols) and LDAP over Unix sockets (LDAPI). The Directory Server can establish a secure
(encrypted) connection with SSL/TLS, depending on whether the client negotiates the use of Transport
Layer Security (TLS) for the connection.
When communication takes place with TLS, the communication is usually encrypted. If clients have
been issued certificates, TLS/SSL can be used by Directory Server to confirm that the client has the
right to access the server. TLS/SSL is used to perform other security activities, such as message
integrity checks, digital signatures, and mutual authentication between servers.
NOTE
Directory Server runs as a daemon; the process is ns-slapd.
1.2.2. Server Plug-ins Overview
Directory Server relies on plug-ins to add functionality to the core server. For example, a database
layer is a plug-in. Directory Server has plug-ins for replication, chaining databases, and other different
directory functions.
Generally, a plug-in can be disabled, particularly plug-ins the extend the server functionality. When
disabled, the plug-in's configuration information remains in the directory, but its function is not used
by the server. Depending on what the directory is supposed to do, any of the plug-ins provided with
Directory Server can be enabled to extend the Directory Server functionality. (Plug-ins related to the
core directory service operations, like backend database plug-in, naturally cannot be disabled.)
For more information on the default plug-ins with Directory Server and the functions available for
writing custom plug-ins, see the Directory Server Plug-in Programmer's Guide.
1.2.3. Overview of the Basic Directory Tree
The directory tree, also known as a directory information tree (DIT), mirrors the tree model used
by most file systems, with the tree's root, or first entry, appearing at the top of the hierarchy. During
installation, Directory Server creates a default directory tree.

Chapter 1. Introduction to Directory Services
4
Figure 1.1. Layout of Default Directory Server Directory Tree
The root of the tree is called the root suffix. For information about naming the root suffix, see
Section 4.2.1, “Choosing a Suffix”.
After a standard installation, the directory contains three subtrees under the root suffix:
•cn=config, the subtree containing information about the server's internal configuration.
•o=NetscapeRoot, the subtree containing the configuration information of the Directory Server and
Administration Server.
NOTE
When additional instances of Directory Server are installed, they can be configured not
to have an o=NetscapeRoot database; in that case, the instances use a configuration
directory (or the o=NetscapeRoot subtree) on another server. See the Directory
Server Installation Guide for more information about choosing the location of the
configuration directory.
•cn=monitor, the subtree containing Directory Server server and database monitoring statistics.
•cn=schema, the subtree containing the schema elements currently loaded in the server.
•user_suffix, the suffix for the default user database created when the Directory Server is setup. The
name of the suffix is defined by the user when the server is created; the name of the associated
database is userRoot. The database can be populated with entries by importing an LDIF file at
setup or entries can be added to it later.
The user_suffix suffix frequently has a dc naming convention, like dc=example,dc=com.
Another common naming attribute is the o attribute, which is used for an entire organization, like
o=example.com.
The default directory tree can be extended to add any data relevant to the directory installation. For
more information about directory trees, see Chapter 4, Designing the Directory Tree.

Directory Server Data Storage
5
Figure 1.2. Expanded Directory Tree for Example Corp.
1.3. Directory Server Data Storage
The database is the basic unit of storage, performance, replication, and indexing. All Directory Server
operations — importing, exporting, backing up, restoring, and indexing entries — are performed on the
database. Directory data are stored in an LDBM database. The LDBM database is implemented as a
plug-in that is automatically installed with the directory and is enabled by default.
By default, Directory Server uses one backend database instance for a root suffix, and, by default,
there are two databases, o=NetscapeRoot for configuration entries and userRoot for directory
entries. A single database is sufficient to contain the directory tree. This database can manage millions
of entries.
This database supports advanced methods of backing up and restoring data, in order to minimize risk
to data.
NOTE
For database files that are larger than 2 gigabytes, 32-bit HP-UX machines must be
configured to support large files. Use the vxfs file system and set the largefiles option
to on.
Multiple databases can be used to support the whole Directory Server deployment. Information is
distributed across the databases, allowing the server to hold more data than can be stored in a single
database.
1.3.1. About Directory Entries
LDAP Data Interchange Format (LDIF) is a standard text-based format for describing directory
entries. An entry consists of a number of lines in the LDIF file (also called a stanza), which contains
information about an object, such as a person in the organization or a printer on the network.
Information about the entry is represented in the LDIF file by a set of attributes and their values. Each
entry has an object class attribute that specifies the kind of object the entry describes and defines the
set of additional attributes it contains. Each attribute describes a particular trait of an entry.

Chapter 1. Introduction to Directory Services
6
For example, an entry might be of object class organizationalPerson, indicating that the
entry represents a person within an organization. This object class supports the givenname and
telephoneNumber attributes. The values assigned to these attributes give the name and phone
number of the person represented by the entry.
Directory Server also uses read-only attributes that are calculated by the server. These attributes are
called operational attributes. The administrator can manually set operational attributes that can be
used for access control and other server functions.
1.3.1.1. Performing Queries on Directory Entries
Entries are stored in a hierarchical structure in the directory tree. LDAP supports tools that query the
database for an entry and request all entries below it in the directory tree. The root of this subtree is
called the base distinguished name, or base DN. For example, if performing an LDAP search request
specifying a base DN of ou=people, dc=example,dc=com, then the search operation examines
only the ou=people subtree in the dc=example,dc=com directory tree.
Not all entries are automatically returned in response to an LDAP search, however, because
administrative entries (which have the ldapsubentry object class) are not returned by default with
LDAP searches. Administrative object, for example, can be entries used to define a role or a class of
service. To include these entries in the search response, clients need to search specifically for entries
with the ldapsubentry object class. See Section 4.3.1, “About Roles” for more information about
roles and Section 4.3.3, “About Class of Service” for more information about class of service.
1.3.2. Distributing Directory Data
When various parts of the directory tree are stored in separate databases, the directory can process
client requests in parallel, which improves performance. The databases can even be located on
different machines to further improve performance.
Distributed data are connected by a special entry in a subtree of the directory, called a database link,
which point to data stored remotely. When a client application requests data from a database link,
the database link retrieves the data from the remote database and returns it to the client. All LDAP
operations attempted below this entry are sent to the remote machine. This method is called chaining.
Chaining is implemented in the server as a plug-in, which is enabled by default.
1.4. Directory Design Overview
Planning the directory service before actual deployment is the most important task to ensure the
success of the directory. The design process involves gathering data about the directory requirements,
such as environment and data sources, users, and the applications that use the directory. This
information is integral to designing an effective directory service because it helps identify the
arrangement and functionality required.
The flexibility of Directory Server means the directory design can be reworked to meet unexpected or
changing requirements, even after the Directory Server is deployed.
1.4.1. Design Process Outline
1. Chapter 2, Planning the Directory Data
The directory contains data such as user names, telephone numbers, and group details. This
chapter analyzes the various sources of data in the organization and understand their relationship

Deploying the Directory
7
with one another. It describes the types of data that can be stored in the directory and other tasks
to perform to design the contents of the Directory Server.
2. Chapter 3, Designing the Directory Schema
The directory is designed to support one or more directory-enabled applications. These
applications have requirements of the data stored in the directory, such as the file format. The
directory schema determines the characteristics of the data stored in the directory. The standard
schema shipped with Directory Server is introduced in this chapter, as well as a description of how
to customize the schema and tips for maintaining a consistent schema.
3. Chapter 4, Designing the Directory Tree
Along with determining what information is contained in the Directory Server, it is important to
determine how that information is going to be organized and referenced. This chapter introduces
the directory tree and gives an overview of the design of the data hierarchy. Sample directory tree
designs are also provided.
4. Chapter 5, Designing the Directory Topology
Topology design means how the directory tree is divided among multiple physical Directory
Servers and how these servers communicate with one another. The general principles behind
design, using multiple databases, the mechanisms available for linking the distributed data
together, and how the directory itself keeps track of distributed data are all described in this
chapter.
5. Chapter 6, Designing the Replication Process
When replication is used, multiple Directory Servers maintain the same directory data to increase
performance and provide fault tolerance. This chapter describes how replication works, what kinds
of data can be replicated, common replication scenarios, and tips for building a high-availability
directory service.
6. Chapter 7, Designing Synchronization
The information stored in the Red Hat Directory Server can by synchronized with information
stored in Microsoft Active Directory databases for better integration with a mixed-platform
infrastructure. This chapter describes how synchronization works, what kinds of data can be
synched, and considerations for the type of information and locations in the directory tree which
are best for synchronization.
7. Chapter 8, Designing a Secure Directory
Finally, plan how to protect the data in the directory and design the other aspects of the service
to meet the security requirements of the users and applications. This chapter covers common
security threats, an overview of security methods, the steps involved in analyzing security needs,
and tips for designing access controls and protecting the integrity of the directory data.
1.4.2. Deploying the Directory
The first step to deploying the Directory Server is installing a test server instance to make sure the
service can handle the user load. If the service is not adequate in the initial configuration, adjust the
design and test it again. Adjust the design until it is a robust service that you can confidently introduce
to the enterprise.

Chapter 1. Introduction to Directory Services
8
For a comprehensive overview of creating and implementing a directory pilot, see Understanding and
Deploying LDAP Directory Services (T. Howes, M. Smith, G. Good, Macmillan Technical Publishing,
1999).
After creating and tuning a successful test Directory Server instance, develop a plan to move the
directory service to production which covers the following considerations:
• An estimate of the required resources
• A schedule of what needs to be accomplished and when
• A set of criteria for measuring the success of the deployment
See the Directory Server Installation Guide for information on installing the directory service and the
Directory Server Administrator's Guide for information on administering and maintaining the directory.
1.5. Other General Directory Resources
The following publications have very detailed and useful information about directories, LDAP, and
LDIF:
• RFC 2849: The LDAP Data Interchange Format (LDIF) Technical Specification, http://www.ietf.org/
rfc/rfc2849.txt
• RFC 2251: Lightweight Directory Access Protocol (v3), http://www.ietf.org/rfc/rfc2251.txt
•Understanding and Deploying LDAP Directory Services. T. Howes, M. Smith, G. Good, Macmillan
Technical Publishing, 1999.
All of the Red Hat Directory Server documentation, available at http://redhat.com/docs/manuals/dir-
server, also contain high-level concepts about using LDAP and managing directory services, as well
as Directory Server-specific information.

Chapter 2.
9
Planning the Directory Data
The data stored in the directory may include user names, email addresses, telephone numbers, and
information about groups users are in, or it may contain other types of information. The type of data in
the directory determines how the directory is structured, who is given access to the data, and how this
access is requested and granted.
This chapter describes the issues and strategies behind planning the directory's data.
2.1. Introduction to Directory Data
Some types of data are better suited to the directory than others. Ideal data for a directory has some of
the following characteristics:
• It is read more often than written.
• It is expressible in attribute-data format (for example, surname=jensen).
• It is of interest to more than one person or group. For example, an employee's name or the physical
location of a printer can be of interest to many people and applications.
• It will be accessed from more than one physical location.
For example, an employee's preference settings for a software application may not seem to be
appropriate for the directory because only a single instance of the application needs access to the
information. However, if the application is capable of reading preferences from the directory and users
might want to interact with the application according to their preferences from different sites, then it is
very useful to include the preference information in the directory.
2.1.1. Information to Include in the Directory
Any descriptive or useful information about a person or asset can be added to an entry as an attribute.
For example:
• Contact information, such as telephone numbers, physical addresses, and email addresses.
• Descriptive information, such as an employee number, job title, manager or administrator
identification, and job-related interests.
• Organization contact information, such as a telephone number, physical address, administrator
identification, and business description.
• Device information, such as a printer's physical location, type of printer, and the number of pages
per minute that the printer can produce.
• Contact and billing information for a corporation's trading partners, clients, and customers.
• Contract information, such as the customer's name, due dates, job description, and pricing
information.
• Individual software preferences or software configuration information.
• Resource sites, such as pointers to web servers or the file system of a certain file or application.

Chapter 2. Planning the Directory Data
10
Using the Directory Server for more than just server administration requires planning what other types
of information to store in the directory. For example:
• Contract or client account details
• Payroll data
• Physical device information
• Home contact information
• Office contact information for the various sites within the enterprise
2.1.2. Information to Exclude from the Directory
Red Hat Directory Server is excellent for managing large quantities of data that client applications
read and write, but it is not designed to handle large, unstructured objects, such as images or other
media. These objects should be maintained in a file system. However, the directory can store pointers
to these kinds of applications by using pointer URLs to FTP, HTTP, and other sites.
2.2. Defining Directory Needs
When designing the directory data, think not only of the data that is currently required but also how the
directory (and organization) is going to change over time. Considering the future needs of the directory
during the design process influences how the data in the directory are structured and distributed.
Look at these points:
• What should be put in the directory today?
• What immediate problem is solved by deploying a directory?
• What are the immediate needs of the directory-enabled application being used?
• What information is going to be added to the directory in the near future? For example, an enterprise
might use an accounting package that does not currently support LDAP but will be LDAP-enabled in
a few months. Identify the data used by LDAP-compatible applications, and plan for the migration of
the data into the directory as the technology becomes available.
• What information might be stored in the directory in the future? For example, a hosting company
may have future customers with different data requirements than their current customers, such as
needing to store images or media files. While this is the hardest answer to anticipate, doing so may
pay off in unexpected ways. At a minimum, this kind of planning helps identify data sources that
might not otherwise have been considered.
2.3. Performing a Site Survey
A site survey is a formal method for discovering and characterizing the contents of the directory.
Budget plenty of time for performing a site survey, as preparation is the key to the directory
architecture. The site survey consists of a number of tasks:
• Identify the applications that use the directory.
Determine the directory-enabled applications deployed across the enterprise and their data needs.