What is Active Directory (AD)? All You Need to Know

By Tibor Moes / Updated: June 2023

What is Active Directory (AD)? All You Need to Know (2023)<br />

What is Active Directory (AD)?

In the ever-evolving world of information technology, managing and securing identities and resources is crucial. One powerful tool that has revolutionized this process is Microsoft’s Active Directory.

But what exactly is Active Directory, and why should you care about it? Let’s dive into this fascinating world to explore the ins and outs of Active Directory (AD) and unveil its secrets, so you’re well-equipped to protect your organization’s digital assets.


  • Active Directory is a directory service created by Microsoft that enables administrators to manage user access to network resources.

  • It allows administrators to store, retrieve and manage data about users, computers, networks, applications, and services in a secure and centralized database.

  • The main purpose of Active Directory is to provide an easy way for organizations to secure and manage their network resources.

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Understanding Active Directory: A Comprehensive Guide

Active Directory is Microsoft’s service aimed at domain networks. It provides directory and identity management specifically for Windows. It acts as a centralized hub, storing information about network users, such as names, phone numbers, and passwords, as well as resources like servers, storage volumes, and printers. Active Directory relies on a variety of protocols to maintain security and networking. These include LDAP (Lightweight Directory Access Protocol), DNS (Domain Name System) and Microsoft’s Kerberos authentication protocol. The goal of Active Directory is to simplify the management of the organization’s IT infrastructure by providing a single point of control for user accounts, computer objects, groups, policies, and other network resources.

One of the key components of Active Directory is Active Directory Domain Services (AD DS), which is responsible for managing user access to resources and group policies. The domain controller is the server that hosts AD DS. It is an essential element of a network infrastructure. Active Directory’s schema ensures support for different objects. These objects are User, Group, Contact, Computer, Shared Folder, Printer, and Organizational Unit. Each of these has its own set of descriptive attributes.

Moreover, Active Directory has evolved over the years, with Azure AD now offering a cloud-based version of the service, providing more flexibility and scalability.

Key Components of Active Directory

Active Directory consists of several services that expand its directory management capabilities. The main service is Active Directory Domain Services (AD DS). AD DS provides authentication and authorization, deciding which users have access to specific resources and managing group policies. Other services offered by Active Directory include Lightweight Directory Services (AD LDS), Certificate Services (AD CS), Federation Services (AD FS), and Rights Management Services (AD RMS). Each of these services plays a unique role in enhancing the functionality and security of the Active Directory.

For instance, AD LDS is a service that can run alongside AD DS, allowing multiple AD LDS instances to run on the same server, providing more flexibility and scalability for directory-based applications. On the other hand, AD CS offers digital certificate management, enabling secure communication between users, computers, and applications within an organization. AD FS provides single sign-on (SSO) capabilities for web-based applications, while AD RMS delivers information protection by controlling access to sensitive documents and files.

These services work together to make Active Directory a robust and powerful directory management solution. The domain controller, the server that hosts AD DS, plays a vital role in managing and securing network resources. By understanding the key components of Active Directory, you can harness its full potential to manage and secure your organization’s IT infrastructure.

Organizing Data in Active Directory: Domains, Trees, and Forests

To better organize and manage directory data, Active Directory uses a hierarchical structure consisting of domains, trees, and forests. This tiered structure allows administrators to efficiently manage resources, permissions, and security settings within their network.

Let’s delve deeper into these concepts and understand how they work together in the Active Directory environment.


A domain in Active Directory is an administrative boundary. It contains a collection of objects, such as users, groups and devices, that share the same Active Directory database. These objects are organized in a hierarchical structure, allowing administrators to control and manage them more effectively. Domains enable centralized control and provide a single point of management for user accounts, computer objects, groups, policies, and other network resources.

Domains can be further organized into parent and child domains, which create a hierarchical structure within the Active Directory tree. This structure allows for easy delegation of administrative tasks and control over resources, ensuring that only authorized users have access to sensitive data and systems.


An Active Directory tree is a hierarchical collection of domains within a Microsoft Active Directory network. Trees consist of parent and child domains, where the parent domain acts as the root, and child domains branch out from it. This structure allows for efficient organization and management of resources across multiple domains.

Trees within Active Directory share a common schema, configuration, and global catalog, which helps streamline the management of resources and security settings. By organizing domains into trees, administrators can manage multiple domains more effectively and ensure that the right users have access to the right resources.


An Active Directory forest is the top-level container of an Active Directory setup, consisting of one or more domain trees that have the same schema, configuration, and global catalog. Forests provide security boundaries within Active Directory, ensuring that users and resources can only access data and systems within their own forest.

Forests play a crucial role in securing the Active Directory environment, as they help prevent unauthorized access to sensitive information and systems. By grouping trees into forests, administrators can maintain a high level of security and control over their organization’s IT infrastructure, while still benefiting from the scalability and flexibility of a multi-domain setup.

Trust Relationships and Access Control in Active Directory

Trust relationships are an essential aspect of Active Directory security and access management. A trust relationship is a secure connection between two domains, allowing users from one domain to access resources in the other. Active Directory supports various types of trusts, including external trusts, forest trusts, shortcut trusts, and realm trusts. Trust relationships help control and manage access rights between domains, ensuring that only authorized users can access specific resources.

By using trust relationships, administrators can effectively manage user access and permissions across multiple domains, maintaining a high level of security within their organization’s IT infrastructure. By understanding the different types of trusts and their role in access control, administrators can better protect their Active Directory environment from potential threats and unauthorized access.

Evolution of Active Directory: From Windows Server to Azure AD

Active Directory has come a long way since its inception in 2000 with Windows 2000 Server. Over the years, various updates and security measures have been added with each Windows Server release, up to Windows Server 2016, which introduced Privileged Access Management (PAM). PAM helps prevent attackers from gaining access to privileged accounts, enabling organizations to audit and monitor these accounts and restrict access.

Another significant milestone in the evolution of Active Directory is the release of Azure Active Directory (Azure AD). Azure AD is a cloud-based identity and access management service that can be linked with an on-premises Active Directory system using Azure AD Connect. This integration provides single sign-on capabilities for Microsoft’s cloud services, such as Office 365, offering organizations more flexibility and scalability in managing their directory services.

Comparing Domains and Workgroups: Which is Right for Your Network?

Domains and workgroups are two ways to organize Windows machines in a network. Domains are mainly used for larger public or business networks, providing centralized control and scalability. In contrast, workgroups are better suited for smaller local area networks, such as schools, where control over individual computers is desired, and setup is more straightforward.

When choosing between domains and workgroups for your organization, consider the size, security, and management needs of your network. Domains offer more security and centralized management, making them ideal for larger organizations with numerous users and resources. On the other hand, workgroups are simpler to set up and manage, making them a suitable choice for smaller networks that require more control over individual computers.

Securing Active Directory Against Cyber Threats

Cyber threats targeting Active Directory can have severe consequences for an organization’s IT infrastructure. To mitigate these risks, it is essential to employ tools and best practices that secure your Active Directory environment. One such tool is Privileged Access Management (PAM), which offers session monitoring, granular access controls, and password vaulting to protect against unauthorized access.

Let’s take a closer look at the various attack methods, PAM tools, and best practices for securing Active Directory.

Common Attack Methods

Attackers use various techniques to target Active Directory, including reconnaissance, default credentials, Kerberoasting, Pass-the-Hash, Pass-the-Ticket, and privilege escalation. Reconnaissance involves gathering information about a target system or network to identify potential vulnerabilities and gain access to user accounts. Default credentials refer to pre-loaded user accounts with a username and password that attackers can exploit to gain access to a system or network.

Kerberoasting is a technique used by attackers to crack passwords stored in Kerberos tickets, allowing them to gain access to user accounts. Pass-the-Hash and Pass-the-Ticket methods involve stealing user’s password hash or Kerberos ticket, respectively, to access user accounts.

Privilege escalation is another method used by attackers to exploit weak points in the system or network and gain access to user accounts with higher privileges. Awareness of these common attack methods is vital in securing your Active Directory environment.

Privileged Access Management (PAM)

Privileged Access Management (PAM) is an essential tool in securing Active Directory against cyber threats. PAM helps monitor who has access to an object, what kind of access they have, and what they do with it, ensuring that only authorized users have access to sensitive data and systems. PAM offers an extra layer of security through the introduction of a bastion AD forest. This creates an isolated environment, ensuring the safety of data.

Using PAM tools like session monitoring, granular access controls, and password vaulting can significantly enhance the security of your Active Directory environment. By implementing PAM, you can better protect your organization’s IT infrastructure from potential threats, unauthorized access, and ensure that only authorized users have access to sensitive information and systems.

Best Practices for Active Directory Security

Implementing best practices for Active Directory security is crucial in protecting your organization’s IT infrastructure from potential threats. Some practical tips include using two accounts for each user, one for everyday tasks and another for administrative tasks. This approach ensures that regular users don’t have access to admin tasks, and admins don’t accidentally perform regular tasks with elevated privileges.

Other best practices include securing domain administrator accounts with strong passwords, two-factor authentication, and regular user account audits. Implementing the principle of least privilege to ensure users only have access to what they need to do their job is another vital step in securing Active Directory.

By following these best practices, you can significantly enhance the security of your Active Directory environment and protect your organization’s valuable digital assets.

Alternatives to Active Directory: Exploring Competitor Solutions

While Active Directory is a powerful and widely used directory service, there are alternative solutions available that may better suit specific organizational needs. Some major competitors include Red Hat Directory Server, Apache Directory, and OpenLDAP. These solutions provide similar directory services and security features, but may differ in terms of scalability, performance, and ease of management.

For organizations looking for cloud-based alternatives, options such as JumpCloud Directory Platform, Microsoft Azure Active Directory, and Google Workspace offer flexibility and scalability in managing directory services. By exploring these competitor solutions, you can determine the best-fit directory service for your organization’s unique requirements and ensure that your IT infrastructure remains secure and well-managed.


We’ve explored the fascinating world of Active Directory, diving deep into its various components, hierarchical structure, trust relationships, and security best practices. We’ve also compared domains and workgroups to help you determine the best option for your network and looked at alternative solutions to Active Directory for those seeking different options.

Understanding and securing your Active Directory environment is crucial in today’s digital world. By implementing the best practices and tools discussed in this article, you can protect your organization’s valuable digital assets and ensure that your IT infrastructure remains secure and well-managed. So, are you ready to take control of your Active Directory and safeguard your organization’s future?

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Frequently Asked Questions

Below are the most frequently asked questions.

What is meant by Active Directory?

Active Directory is a directory service created by Microsoft that enables administrators to manage user access to network resources. It allows administrators to store, retrieve and manage data about users, computers, networks, applications, and services in a secure and centralized database.

Active Directory also provides tools to help administrators control user access to the network.

What are the main purposes of Active Directory?

The main purpose of Active Directory is to provide an easy way for organizations to secure and manage their network resources. It enables admins to control user permissions, create group policies, and set up directory-based structures that make it easier to access and share files.

Active Directory provides a centralized system for managing user accounts, controlling access to resources on corporate networks, and creating and enforcing security policies. It stores information about objects on the network in an organized structure, making it easier for administrators and users to access data.

What are the 3 main functions of Active Directory?

With Active Directory Domain Services, you can enjoy the benefits of centralized resources and security administration, single login for access to global resources, and simplified resource location.

These three functions make it an invaluable tool for any organization.

What is Active Directory quizlet?

Active Directory is a secure database used by companies to store their user accounts and passwords in one place, providing added security and simplifying the process of managing employee access rights. With Active Directory, companies can ensure that their data remains secure and protected.

Author: Tibor Moes

Author: Tibor Moes

Founder & Chief Editor at SoftwareLab

Tibor has tested 39 antivirus programs and 30 VPN services, and holds a Cybersecurity Graduate Certificate from Stanford University.

He uses Norton to protect his devices, CyberGhost for his privacy, and Dashlane for his passwords.

You can find him on LinkedIn or contact him here.