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Oracle Internet Directory Administrator's Guide
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2 Introduction to LDAP and Oracle Internet Directory

This chapter introduces online directories, provides an overview of the Lightweight Directory Application Protocol (LDAP) version 3, and explains some of the unique features and benefits of Oracle Internet Directory.

This chapter contains these topics:

2.1 What Is a Directory?

A directory is a way in which complex information is organized, making it easy to find. Directories list resources—for example, people, books in a library, or merchandise in a department store—and give details about each one. They can be either offline—for example, a telephone book or a department store catalog—or online.

Online directories are used by enterprises with distributed computer systems for fast searches, cost-effective management of users and security, and as central integration points for multiple applications and services. Online directories are also becoming critical to both e-businesses and hosted environments.

This section contains these topics:

2.1.1 The Expanding Role of Online Directories

An online directory is a specialized database that stores and retrieves collections of information about objects. Such information can represent any resources that require management: employee names, titles, and security credentials; information about partners; or information about shared network resources such as conference rooms and printers.

Online directories can be used by a variety of users and applications, and for a variety of purposes, including:

  • An employee searching for corporate white page information, and, through a mail client, looking up e-mail addresses

  • An application, such as a message transport agent, locating a user's mail server

  • A database application identifying role information for a user

Although an online directory is a database—that is, a structured collection of data—it is not a relational database. The following table contrasts online directories with relational databases.

Table 2-1 Comparison of Online Directories and Relational Databases

Online Directories Relational Databases

Primarily read-focused. Typical use involves a relatively small number of data updates, and a potentially large number of data retrievals.

Primarily write-focused. Typical use involves continuous recording of transactions, with retrievals done relatively infrequently.

Designed to handle relatively simple transactions on relatively small units of data. For example, an application might use a directory simply to store and retrieve an e-mail address, a telephone number, or a digital portrait.

Designed to handle large and diverse transactions using many operations on large units of data.

Designed to be location-independent. Directory-enabled applications expect, at all times, to see the same information throughout the deployment environment—regardless of which server they are querying. If a queried server does not store the information locally, then it must either retrieve the information or point the client application to it transparently.

Typically designed to be location-specific. While a relational database can be distributed, it usually resides on a particular database server.

Designed to store information in entries. These entries might represent any resource customers wish to manage: employees, e-commerce partners, conference rooms, or shared network resources such as printers. Associated with each entry is a number of attributes, each of which may have one or more values assigned. For example, typical attributes for a person entry might include first and last names, e-mail addresses, the address of a preferred mail server, passwords or other login credentials, or a digitized portrait.

Designed to store information as rows in relational tables.

2.1.2 The Problem: Too Many Special-Purpose Directories

According to some estimates, each of the world's largest companies has an average of 180 different directories, each designated for a special purpose. Add to this the various enterprise applications, each with its own additional directory of user names, and the actual number of special purpose directories becomes even greater.

Managing so many special purpose directories can cause problems:

  • High cost of administration: Administrators must maintain essentially the same information in many different places. For example, when an enterprise hires a new employee, administrators must create a new user identity on the network, create a new e-mail account, add the user to the human-resources database, and set up all applications that the employee may need—for example, user accounts on development, testing, and production database systems. Later, if the employee leaves the company, administrators must reverse the process to disable all these user accounts.

  • Inconsistent data: Because of the large administrative overhead, it can be difficult for multiple administrators, entering redundant information in multiple systems, to synchronize this employee information across all systems. The result can be inconsistent data across the enterprise.

  • Security issues: Each separate directory may have its own password policy—which means that a user may struggle with a variety of user names and passwords, each for a different system.

Today's enterprises need a more general purpose directory infrastructure, one based on a common standard for supporting a wide variety of applications and services.

2.2 What Is the Lightweight Directory Access Protocol (LDAP)?

LDAP is a standard, extensible directory access protocol. It is a common language that LDAP clients and servers use to communicate.

This section contains these topics:

2.2.1 LDAP and Simplified Directory Management

LDAP was conceived as an Internet-ready, lightweight implementation of the International Standardization Organization (ISO) X.500 standard for directory services. It requires a minimal amount of networking software on the client side, which makes it particularly attractive for Internet-based, thin client applications.

The LDAP standard simplifies management of directory information in three ways:

  • It provides all users and applications in the enterprise with a single, well-defined, standard interface to a single, extensible directory service. This makes it easier to rapidly develop and deploy directory-enabled applications.

  • It reduces the need to enter and coordinate redundant information in multiple services scattered across the enterprise.

  • Its well-defined protocol and array of programmatic interfaces make it more practical to deploy Internet-ready applications that leverage the directory.

2.2.2 LDAP Version 3

The most recent version of LDAP, Version 3, was approved as a proposed Internet Standard by the Internet Engineering Task Force (IETF) in December 1997. LDAP Version 3 improves on LDAP Version 2 in several important areas:

  • Globalization Support: LDAP Version 3 allows servers and clients to support characters used in every language in the world.

  • Knowledge references (also called referrals): LDAP Version 3 implements a referral mechanism that allows servers to return references to other servers as a result of a directory query. This makes it possible to distribute directories globally by partitioning a directory information tree (DIT) across multiple LDAP servers.

  • Security: LDAP Version 3 adds a standard mechanism for supporting Simple Authentication and Security Layer (SASL), providing a comprehensive and extensible framework for data security.

  • Extensibility: LDAP Version 3 enables vendors to extend existing LDAP operations through the use of mechanisms called controls. These are extra pieces of information carried along with existing operations, altering the behavior of the operation. When a client application passes a control along with the standard LDAP command, the behavior of the commanded operation is altered accordingly. For example, when a client wants to modify meta-information hidden in the directory, it can send the manageDSAIT control along with the LDAP command.

  • Feature and schema discovery: LDAP Version 3 enables publishing information useful to other LDAP servers and clients, such as the supported LDAP protocols and a description of the directory schema.

    See Also:

2.3 Oracle Identity Management

Oracle Internet Directory is a component of Oracle Identity Management, an integrated infrastructure that provides distributed security services for Oracle products and other enterprise applications. In addition to Oracle Internet Directory, the Oracle Identity Management infrastructure includes the following components and capabilities:

To support enterprise application deployments, a single Oracle Identity Management infrastructure is typically deployed in the enterprise. It can include multiple server and component instances to provide high availability, information localization, and delegated component administration. Each additional application in the enterprise then leverages the shared infrastructure for identity management services. This deployment model has a number of advantages, including:

2.4 What Is Oracle Internet Directory?

Oracle Internet Directory is a general purpose directory service that enables fast retrieval and centralized management of information about dispersed users and network resources. It combines Lightweight Directory Access Protocol (LDAP) Version 3 with the high performance, scalability, robustness, and availability of an Oracle Database.

This section contains these topics:

2.4.1 Overview of Oracle Internet Directory

Oracle Internet Directory runs as an application on an Oracle Database. It communicates with the database by using Oracle Net Services, Oracle's operating system-independent database connectivity solution. The database may or may not be on the same host. Figure 2-1 illustrates this relationship.

Figure 2-1 Oracle Internet Directory Overview

Description of Figure 2-1 follows
Description of "Figure 2-1 Oracle Internet Directory Overview"

2.4.2 Components of Oracle Internet Directory

Oracle Internet Directory includes:

  • Oracle directory server, which responds to client requests for information about people and resources, and to updates of that information, by using a multitiered architecture directly over TCP/IP

  • Oracle directory replication server, which replicates LDAP data between Oracle directory servers

  • Directory administration tools, which include:

    • Oracle Directory Manager, which simplifies directory administration through a Java-based graphical user interface

    • A variety of command-line administration and data management tools invoked from LDAP clients

    • Directory server management tools within Oracle Enterprise Manager 10g Application Server Control Console. These tools enable you to:

      • Monitor real-time events and statistics from a normal browser

      • Start the process of collecting such data into a new repository

  • Oracle Internet Directory Software Developer's Kit

    See Also:

    Oracle Identity Management Application Developer's Guide for information about the Oracle Internet Directory Software Developer's Kit

2.4.3 Advantages of Oracle Internet Directory

Among its more significant benefits, Oracle Internet Directory provides scalability, high availability, security, and tight integration with the Oracle environment. Scalability

Oracle Internet Directory exploits the strengths of an Oracle Database, enabling support for terabytes of directory information. In addition, such technologies as shared LDAP servers and database connection pooling enable it to support thousands of concurrent clients with subsecond search response times.

Oracle Internet Directory also provides data management tools, such as Oracle Directory Manager and a variety of command-line tools, for manipulating large volumes of LDAP data. High Availability

Oracle Internet Directory is designed to meet the needs of a variety of important applications. For example, it supports full multimaster replication between directory servers: If one server in a replication community becomes unavailable, then a user can access the data from another server. Information about changes to directory data on a server is stored in special tables on the Oracle Database. These are replicated throughout the directory environment by Oracle Database Advanced Replication, a robust replication mechanism.

Oracle Internet Directory also takes advantage of all the availability features of the Oracle Database. Because directory information is stored securely in the Oracle Database, it is protected by Oracle's backup capabilities. Additionally, the Oracle Database, running with large data stores and heavy loads, can recover from system failures quickly. Security

Oracle Internet Directory offers comprehensive and flexible access control. An administrator can grant or restrict access to a specific directory object or to an entire directory subtree. Moreover, Oracle Internet Directory implements three levels of user authentication: anonymous, password-based, and certificate-based using Secure Sockets Layer (SSL) Version 3 for authenticated access and data privacy. Integration with the Oracle Environment

Through Oracle Directory Integration Platform, Oracle Internet Directory provides a single point of integration between the Oracle environment and other directories such as NOS directories, third-party enterprise directories, and application-specific user repositories.

2.5 How Oracle Components Use Oracle Internet Directory

Oracle components use Oracle Internet Directory for easier administration, tighter security, and simpler integration between multiple directories.

This section contains these topics:

2.5.1 Easier and More Cost-Effective Administration of Applications

OracleAS Portal enables self-service, integrated enterprise portals to store common user and group attributes in Oracle Internet Directory. The Oracle Portal administration tool also leverages the Oracle Delegated Administration Services for certain tasks.

Oracle Collaboration Suite uses Oracle Internet Directory for:

  • Centralized management of information about users and groups

  • Provisioning Oracle Collaboration Suite components—that is, notifying them whenever changes of interest are applied to data in Oracle Internet Directory

  • Centralized integration for enterprises connecting other directories with any Oracle Collaboration Suite component

Oracle Net Services uses Oracle Internet Directory to store and resolve database services and the simple names, called net service names, that can be used to represent them.

2.5.2 Tighter Security Through Centralized Security Policy Administration

The Oracle Database uses Oracle Internet Directory to store user names and passwords. It uses Oracle Internet Directory to store a password verifier along with the entry of each user.

Oracle Application Server Single Sign-On uses Oracle Internet Directory to store user entries. It maps users for any partner application to entries in Oracle Internet Directory, and authenticates those users by using LDAP mechanisms.

Oracle Advanced Security uses Oracle Internet Directory for:

  • Central Management of user authentication credentials

    Instead of storing a user's database password in each database, Oracle Advanced Security stores it in one place: the directory. It stores the password as an attribute of the user entry.

  • Central management of user authorizations

    Oracle Advanced Security uses directory entries, called enterprise roles, to determine the privileges for a given enterprise user within a given schema, whether that schema is shared or owned. Enterprise roles are containers for database-specific global roles. For example, a user might be assigned the enterprise role of clerk, which might contain the global role of hrclerk with its attendant privileges on the human resources database and the global role of analyst with its attendant privileges on the payroll database.

  • Mappings to shared schemas

    Oracle Advanced Security uses mappings—that is, directory entries that point an enterprise user to shared application schemas on the database instead of to an individual account. For example, you might map several enterprise users to the schema sales_application instead of to separate accounts in their names.

  • Single password authentication

    In the Oracle Database, Oracle Advanced Security enables enterprise users to authenticate to multiple databases by using a single, centrally managed password. The password is stored in the directory as an attribute of the user's entry and is protected by encryption and access control lists. This spares you from setting up Secure Sockets Layer (SSL) on clients and users from having to remember multiple passwords.

  • Enterprise user security

    The alternative to authenticating with a centrally managed password is to use PKI-based enterprise user security through SSL. Like single password authentication, this feature relies on a user entry in the directory. A user's wallet must be stored as an attribute of his or her entry.

  • Central storage of PKI credentials

    In Oracle Database and Oracle Application Server, user wallets can be stored in the directory as an attribute of the user's entry. This enables mobile users to retrieve and open their wallets by using Enterprise Login Assistant. While the wallet is open, authentication is transparent—that is, users can access any database on which they own or share a schema without having to authenticate again.

2.5.3 Integration of Multiple Directories

Oracle Directory Integration Platform is a collection of interfaces and services for integrating multiple directories by using Oracle Internet Directory and several associated plug-ins and connectors. It provides these benefits:

  • All Oracle components are pre-certified to work with Oracle Internet Directory.

  • You can integrate the entire Oracle environment with third-party directories simply by integrating each third-party directory with Oracle Internet Directory. This saves you from having to integrate each application with each directory.