Domain Controller vs. Active Directory

What’s the Difference?

Written by Kelsey Kinzer on November 2, 2022

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Active Directory (AD) and a domain controller are some of the IT components that are core to organizations using Windows operating systems (OSs). But what’s the difference between them? 

Active Directory is Microsoft’s proprietary directory service. It allows IT teams to manage identity and secure access to various resources on the enterprise network. 

A domain controller, on the other hand, is a server that responds to user authentication requests, allowing the host to access various resources on an enterprise network. 

In this post, we’ll explore the differences between a domain controller versus Active Directory, and how JumpCloud can help you enhance AD or ditch the domain controller altogether. 

Active Directory: Identities and Access

Active Directory is an identity management database that allows IT teams to define what users can do on a network. As a database, Active Directory captures data in the form of objects. An object can be a single resource element, like a user, group, application, or device. 

Each object has associated attributes that allow it to be distinguished from other entities. For example, a user object would have a username, password, and email attributes that distinguish it from other objects. 

Active Directory consists of four essential services that allow it to provide identity and access management:

  • Active Directory Domain Services (AD DS). This is the main service within the Active Directory protocol. Besides storing the directory information, it also controls which users can access each enterprise resource and group policies. AD DS uses a tiered structure comprising the domains, trees, and forests to coordinate networked resources.
  • Active Directory Lightweight Directory Services (AD LDS). It shares the same codebase and functionality as AD DS. However, unlike AD DS, AD LDS uses the Lightweight Directory Access Protocol (LDAP), allowing it to run on multiple instances on the same server. 
  • Active Directory Federation Services (AD FS). As the name suggests, AD FS is a federated identity service that provides single sign-on (SSO) capabilities. It uses many popular protocols such as OAuth, OpenID, and Secure Assertion Markup Language (SAML) to pass credentials between different identity providers. 
  • Active Directory Certificate Services (AD CS). This is a service that creates on-premises public key infrastructure (PKI), allowing organizations to create, validate, and revoke certificates for internal use.

Domain Controller: Validate and Authenticate

A domain controller is a server that processes user authentication requests on a particular domain on an enterprise network. While domain controllers are primarily used in AD domains, you can also use them with other non-Windows identity and access management (IAM) systems, such as Samba and FreeIPA.

A domain controller restricts access to enterprise resources within a given domain by authenticating and authorizing users based on their login credentials. For example, in Windows domains, the domain controller obtains authentication information for user accounts from Active Directory. 

While domain controllers can operate as single systems, they are often implemented in clusters to provide high availability (HA) and reliability services. For example, in Windows Active Directory, each cluster can consist of a primary domain controller (PDC) and a backup domain controller (BDC). In Unix and Linux ecosystems, replica domain controllers replicate authentication databases from the PDC. 

Active Directory vs. Domain Controller

It’s common to think that the terms Active Directory and domain controller are synonymous. This is because domain control is a function within Microsoft’s Active Directory, and domain controllers are servers that leverage AD to validate and respond to authentication requests. 

However, the terms are not interchangeable. Active Directory is a database that stores and organizes enterprise resources as objects. You can think of Active Directory as a database that stores users and device configurations in AD DS. A domain controller, in contrast, is simply a server running Active Directory that authenticates users and devices. In this regard, you can think of a domain controller as a custodian, facilitator, or host of Active Directory. 

Since domain controllers mediate all access to the network resources, it is essential to protect them with additional security mechanisms, such as firewalls, encryption protocols, and expedited configuration and patch management solutions.

Deciding What You Need for a Directory and Domain Controller

Many organizations are looking to implement SSO solutions that allow their employees to access all their on-prem and cloud-based applications easily. 

In the recent past, a vital requirement of these solutions was the domain controller, which made it possible to connect applications back to Active Directory as a single source of truth. Organizations have used AD FS as a solution for integrating Active Directory into cloud-based applications. However, while Microsoft markets AD FS as a “free” solution, there are many hidden costs, including hardware purchase, deployment, and ongoing maintenance, that you have to contend with. 

But suppose you were to decide what you need for a directory or what constitutes a complete IAM solution today. Such a solution should provide automated provisioning of resources, lifecycle management, mobile device management (MDM), and reporting from a single console. The IAM solution should also be vendor-agnostic, unlike Active Directory, which excels at managing access to on-prem Windows-based OSs. The IT environments of today simply don’t look like that anymore.

The JumpCloud Directory Platform® is a low-cost, cloud-based directory management solution that simplifies AD integration, allowing IT teams to unify IAM and consolidate tooling while enhancing Active Directory’s functionality. Organizations can also leverage JumpCloud as an AD replacement tool, reducing the on-prem servers required to set up AD FS and moving to a domainless enterprise

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Kelsey Kinzer

Kelsey is a passionate storyteller and Content Writer at JumpCloud. She is particularly inspired by the people who drive innovation in B2B tech. When away from her screen, you can find her climbing mountains and (unsuccessfully) trying to quit cold brew coffee.

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