Decommissioning On-Premise Active Directory: A Key Step in Modernizing Your IT Infrastructure

In the ever-evolving landscape of IT, organizations are increasingly realizing the need to move away from traditional, on-premises infrastructures like Active Directory (AD). This shift is driven by the desire for greater flexibility, scalability, and security, which modern cloud solutions can offer. A critical milestone in this journey is transitioning from reliance on AD to a more modern identity and access management solution like Microsoft Entra ID (formerly Azure Active Directory). In this post, we’ll explore this journey, breaking it down into three key steps that will set your organization on the path to a cloud-first future.

Quick Synopsis of the Journey to Moving Away from Active Directory

• Step 1: Joining Devices to Entra ID
  • Transition from traditional AD domain-joined devices to Entra ID (Azure AD) joined devices.
  • Shift device management from Group Policy Objects (GPOs) to modern tools like Microsoft Endpoint Manager (MEM) and Intune.
  • Enable cloud-based security and management, enhancing flexibility for remote and hybrid work.
• Step 2: Modernizing the Application Stack
  • Assess and migrate legacy applications to cloud-native or SaaS solutions.
  • Reduce reliance on AD-integrated applications by leveraging cloud services.
  • Enhance security and scalability by moving applications down the cloud continuum.
• Step 3: Phasing Out Non-Identity AD Components
  • Migrate non-identity services like DNS, DHCP, and file shares to cloud-based alternatives.
  • Implement solutions that operate independently of AD, reducing infrastructure complexity.
  • Fully decouple from AD to embrace a cloud-first, agile IT environment.

Step 1: Directly Joining Windows Devices to Entra ID

One of the foundational steps in moving away from AD is to enable Windows devices to join Entra ID directly. This move signifies a shift in how devices are managed within the organization, moving away from the traditional domain-joined model that relies heavily on AD and Group Policy Management (GPM).

By directly joining devices to Entra ID, organizations can leverage modern management tools like Microsoft Endpoint Manager (MEM) and Intune for policy enforcement, security baselines, and application deployment. This eliminates the need for Group Policy Objects (GPOs) and reduces the overhead associated with managing on-premises infrastructure. Additionally, this approach allows for seamless integration with cloud services, enhanced security features such as Conditional Access, and a more streamlined user experience, particularly for remote and hybrid work scenarios.

However, even with devices being directly joined to Entra ID, organizations can still maintain access to on-premises resources through hybrid identities and network line of sight to Active Directory. Hybrid identities allow users and devices to authenticate and access on-prem resources like file shares, printers, and legacy applications that still require integration with Active Directory. This ensures that the transition to cloud-based identity management can occur gradually, without disrupting access to necessary on-prem services. Hybrid identities can be achieved using Azure AD Connect, which synchronizes on-prem AD with Entra ID, providing a seamless authentication experience across cloud and on-prem environments.

This step gives organizations the best of both worlds—a modern cloud identity platform for future growth and continued support for critical on-prem systems as they work through their digital transformation.

Step 2: Evaluating and Modernizing the Application Stack

Once devices are joined to Entra ID, the next logical step is to evaluate the organization’s application stack. Many legacy applications were designed to interact with AD for authentication, authorization, and other identity-related services. As part of the journey away from AD, it’s crucial to assess which applications can be migrated to the cloud, which ones need modernization, and which may need to be replaced entirely.

Moving applications down the cloud continuum involves adopting Software-as-a-Service (SaaS) solutions where possible, refactoring or replatforming critical applications to run on Platform-as-a-Service (PaaS), and ultimately reducing reliance on infrastructure that requires tight integration with AD. This not only simplifies the management of applications but also enhances security, as cloud-native solutions are often built with modern security protocols and are more resilient to threats.

If you already have web-based applications that are on-premises, an good interim step is to front-end the authentication using a reverse proxy like Azure App Proxy, or even better, the more modern Global Secure Access – Private Access solution from Microsoft. This allows not only web-based applications (using 80/443), but now allows private layer 3/4 applications, even thick client apps. More to come on this topic.

The most difficult components are going to be those custom applications that require legacy Kerberos or NTLM authentication. That’s not to say there aren’t solutions, but the planning around this is critical. We will need to consider our options with Entra Domain Services if we’re looking to move away from managing and maintaining our own domain controllers.

Step 3: Phasing Out Non-Identity and Device Components of Active Directory

The final step in this journey is to address the non-identity and device management components that have traditionally been managed by AD. This includes services like DNS, DHCP, certificate services, and file shares, among others. To achieve a full transition away from AD, organizations need to either migrate these services to cloud-native alternatives or implement solutions that no longer require AD dependencies.

For example, DNS and DHCP services can be transitioned to cloud-based services or integrated into network appliances that operate independently of AD. Certificate services can be managed through cloud solutions like Azure Key Vault. File shares can be moved to cloud storage solutions such as OneDrive for Business, SharePoint Online, or Azure Files, all of which offer seamless integration with Entra ID.

By phasing out these components, organizations can fully decouple from AD, significantly reducing the complexity of their IT environments and positioning themselves to take full advantage of the cloud’s benefits.

Conclusion

The journey away from Active Directory is not without its challenges, but it’s a critical step for organizations looking to modernize their IT infrastructure. By directly joining Windows devices to Entra ID, modernizing the application stack, and phasing out non-identity and device management components, organizations can build a more flexible, scalable, and secure environment that meets the demands of today’s business landscape.

As you embark on this journey, remember that each organization’s path will be unique, and careful planning is essential to ensure a smooth transition. However, the benefits of moving away from Active Directory are clear: reduced management overhead, improved security, and the ability to fully embrace the power of the cloud.