Lightweight Directory Access Protocol (LDAP) is a protocol that facilitates access and management of distributed directory information services over an Internet Protocol (IP) network. LDAP is primarily used to store and retrieve data in a hierarchical organization, often pertaining to users, devices, and other resources in a network environment.
Core Features of LDAP
- Hierarchical Structure: LDAP directories are organized in a tree-like structure which allows for efficient information retrieval.
- Protocol Operations: The main operations include search, compare, add, delete, and modify.
- Authentication & Security: Supports various authentication methods and security measures such as SASL (Simple Authentication and Security Layer) and TLS (Transport Layer Security).
Historical Context
LDAP was developed in the early 1990s by Tim Howes and his colleagues at the University of Michigan. It was designed as a lightweight alternative to the X.500 Directory Access Protocol (DAP), simplifying the ability to manage directory services in a less complex and more accessible manner.
LDAP Structure and Components
Naming Model
- Distinguished Names (DN): A unique identifier for each entry.
- Relative Distinguished Names (RDN): Components of a DN.
Entries and Attributes
- Entries: Consist of a collection of attributes.
- Attributes: Symbols or names that describe characteristics of an entry (e.g.,
commonName,mail).
Schema
- Defines rules and structure for directory entries.
LDAP vs. UDDI
LDAP
- Purpose: Managing distributed directory information.
- Use Case: Commonly used in environments requiring information about users, devices, and services.
UDDI (Universal Description, Discovery, and Integration)
- Purpose: Business services and web services discovery.
- Use Case: Focused on publishing and discovering information about web services.
Common Use Cases
- User Authentication: Centralized login for various services.
- Directory Services: Management of user information, network resources, and services.
- Enterprise Integration: Integrating with email systems, intranets, and other administrative tools.
Example LDAP Query
To search for entries with the common name “John Doe”:
ldapsearch -x -LLL -H ldap://hostname -b "dc=example,dc=com" "(cn=John Doe)"
Related Terms
- Active Directory (AD): A directory service developed by Microsoft that uses LDAP as its underlying protocol.
- SASL: Simple Authentication and Security Layer, a framework for authentication and data security in Internet protocols.
- TLS/SSL: Protocols for encrypting network communications.
FAQs about LDAP
What is LDAP used for?
LDAP is used for accessing and managing directory information services, such as user directories, which store information about users, devices, and services within an organization.
How does LDAP authentication work?
LDAP authentication involves validating the credentials provided by a user against the credentials stored in the LDAP directory.
Can LDAP be integrated with other systems?
Yes, LDAP can be integrated with various systems including email systems, applications, and network services to provide centralized directory services and authentication.
References
- Howes, T., Smith, M., & Good, M. (1996). Understanding and Deploying LDAP Directory Services. Addison-Wesley.
- Yeong, W., Howes, T., & Kille, S. (1995). Lightweight Directory Access Protocol. RFC 1777.
Summary
LDAP (Lightweight Directory Access Protocol) remains a crucial protocol for managing and accessing directory information services across IP networks. Its hierarchical structure, security features, and wide application in centralized user management and authentication underscore its continued relevance in modern computing environments.
