What is LDAP?

Lightweight Directory Access Protocol or more commonly known as LDAP is an application protocol used to access and manage directory information over a network. It is primarily used for querying and modifying directory services like Microsoft's Active Directory, OpenLDAP, and other directory systems.

What are typical components that comprise LDAP?

Directory Information Tree (DIT)

This is the hierarchical structure of the directory, which organizes entries like users, groups, and resources.

Distinguished Name (DN)

A unique identifier for each entry in the directory, which is composed of various attributes like the user’s name, role, and domain.

LDAP Entries

These are the individual records in the directory, such as a user's login credentials or contact details.

Attributes

These are properties of an entry (e.g., name, email address, phone number).

Schema

A set of rules that defines the types of data that can be stored in the directory, and their relationships.

Key Elements of LDAP

Directory Services

LDAP is used to interact with directories that store information such as user credentials, organizational structures, and other networked resources.

Client-Server Model

LDAP follows a client-server architecture where the client sends queries or requests to an LDAP server, which responds with the requested data.

Standardized Protocol

Defined by the IETF (Internet Engineering Task Force) in RFC 4511, it is designed for efficient querying and retrieval of data from a directory.

Hierarchical Structure

LDAP directories use a tree-like hierarchical structure, often representing an organization’s domain, where each entry is uniquely identified by a Distinguished Name (DN).

Best known use-cases of LDAP

Authentication & Authorization:

LDAP is commonly employed in network environments to manage authentication and authorization processes. These two functions are crucial for ensuring that users can access resources securely while maintaining appropriate access controls. Here’s a deeper look:

Authentication

LDAP is often the backbone of user login systems. When a user attempts to log in to a system (e.g., a web application or a corporate network), the credentials (usually a username and password) they provide are sent to the LDAP server. The LDAP server then checks if the provided credentials match those stored in the directory service. If the authentication is successful, the server grants the user access.

During the bind operation in LDAP, the client (such as a user’s device) sends the credentials to the server. The server checks these against the directory database to verify if the user exists and if the credentials are correct.

Protocols and Security: The authentication can be done using a simple bind (username and password) or more secure mechanisms like SASL (Simple Authentication and Security Layer). Many organizations prefer using LDAPS (LDAP over SSL) to encrypt the data exchange during the authentication process, protecting user credentials from being intercepted.

Authorization

Once a user is authenticated, authorization determines what resources they can access and what actions they can perform. LDAP directories often store role-based information, user groups, or specific attributes that define a user's level of access to various resources.

Role-Based Access Control (RBAC): LDAP supports RBAC by associating users with roles or groups (e.g., admin, manager, employee). When a user is authenticated, the system can retrieve group memberships from LDAP to determine what resources or systems the user can interact with. For instance, an employee might have access to internal documents, while an HR admin might have elevated permissions to view sensitive employee data.

Fine-Grained Permissions: Directory entries often have specific access control attributes like ACLs (Access Control Lists), which define who can read, modify, or delete specific data entries. For example, certain users might have read-only access to certain parts of the directory, while others may have full control.

Centralized Directory Services

In large corporate or enterprise environments, LDAP serves as a centralized directory service for managing and organizing large amounts of user and resource data. Centralization offers many benefits for IT administration and organizational efficiency:

Unified User Management:

LDAP allows organizations to store all user-related information in one central directory. This can include user accounts, email addresses, contact information, and roles (e.g., job title, department).

When new employees are onboarded, administrators can add their information to the LDAP directory, which is automatically available to other systems (e.g., email servers, access control systems, intranets).

Similarly, when employees leave, their access can be removed quickly by disabling or deleting their LDAP account.

Resource Management:

LDAP can also manage non-user resources, such as network printers, file shares, servers, and email distribution lists. All these resources are stored as directory entries, with relevant access information tied to each one. This makes it easier to manage access to shared resources by directly associating permissions with user accounts and groups.

Integration with Other Systems:

Since LDAP is a standardized protocol, it is commonly integrated into a variety of other systems like email servers, file management systems, and VPNs. By integrating LDAP, an organization ensures that all systems rely on the same, centralized directory for user information, reducing the need for duplicate or inconsistent data.

Single Sign-On (SSO)

LDAP is a key component in implementing Single Sign-On (SSO) systems. SSO allows users to log in once and gain access to multiple applications without needing to enter credentials repeatedly. Here’s how LDAP fits into SSO:

Authentication Across Multiple Systems:

With SSO, users authenticate once with a central authentication service (often based on LDAP). This authentication grants them access to a variety of services and applications that are integrated with the SSO solution. LDAP’s centralized user directory ensures that user credentials are managed in one place, and that authentication data is available to multiple connected systems.

How it works:

When a user logs into an SSO-enabled service, their credentials are verified against the LDAP directory. If they are authenticated, the SSO system generates a token (often using protocols like SAML, OAuth, or OpenID Connect), which is then shared with other connected applications. As long as the token remains valid, the user does not need to authenticate again for each service.

Improved Security and User Experience:

  • Security: By using LDAP in SSO, organizations ensure that all authentication requests are handled centrally and consistently, which can reduce security risks associated with credential management across multiple systems.
  • Convenience: SSO improves user experience because employees or users only need to remember one set of credentials for accessing a wide variety of systems and applications, from email to internal databases and cloud services.
  • LDAP and Identity Federation: LDAP-based directories often form the backbone of identity federation systems, which allow users to authenticate across different organizations or domains. For example, an LDAP directory may serve as a source of identity for a federated identity system where users from different organizations can access shared resources with their existing credentials.

How does LDAP work

LDAP is a protocol used to access and manage directory information, typically for authentication and resource management.Simply put, think of it as a digital phonebook where user details, like usernames, passwords, and permissions, are stored and easily checked. LDAP is commonly used in organizations to manage employee access to systems and applications efficiently.

Here’s how a typical LDAP process works:

Client Request:

A client (user or application) connects to an LDAP server to authenticate or query directory data.

Bind Operation:

The client sends a Bind request with a Distinguished Name (DN) and password to authenticate. The server validates the credentials.

Directory Operations:

Once authenticated, the client can query (search) or modify directory data, such as retrieving user details, group memberships, or access permissions.

Access Control:

The LDAP server checks the user's permissions (through access control lists or roles) to grant or deny access to requested resources.

Unbind Operation:

Once the tasks are complete, the client sends an Unbind request to terminate the session.

Explore More Glossary Entries

IAM

Empower your organization's security at every endpoint — manage digital identities and control ...

Read more

Automated Provisioning

Automated provisioning is a super-efficient assistant for your IT tasks. Instead of manually se...

Read more

Single Sign On

Single Sign-on (SSO) is an authentication method allowing enterprise users to access multiple a...

Read more

Conditional
Access

Conditional access is a modern security approach that integrates user and device identity into ...

Read more

Identity as a
service

Identity as a Service (IDaaS) offers organizations a cloud-based identity solution managed by s...

Read more

Identity Lifecycle Management

Identity Lifecycle Management (ILM) manages user identities from onboarding to offboarding, ens...

Read more
Get a Demo