On-Prem AD vs. Hybrid Azure AD Join vs. Azure AD: Key Differences

The most difficult aspect of moving from traditional to modern management for Windows 10 is deciding whether to use on-premises AD, Azure AD, or a hybrid of the two. In this article, we will compare AD DS with Azure AD and see what our standard Active Directory can achieve that Azure AD cannot. We’ll also take a look at how Microsoft is implementing a hybrid solution and why it might be useful for some companies.

Once upon a time, every Windows enterprise was flat. Active Directory was the single container that stored all of your domain’s data objects. Back then we just called it AD because it was the only form of AD. It was supported by three pillars: Domain Controllers, DNS, and Group Policy. It was an architecture that served many businesses well for nearly two decades. And then Azure came along, and suddenly in some circles, traditional AD is now called legacy AD. Azure AD, of course, exists in the cloud, the sweet spot most organizations seem to want to move to. Because it’s cloud-based, it uses different protocols and methodologies to authenticate accounts and enforce policies. In a way, on-premises AD and Azure AD are like water and oil because they are very different.

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Key differences between On-Prem AD, Hybrid Azure AD Join and Azure AD

The primary limitation of the local HELL

Many companies started their journey to cloud migration years ago. However, the telecommuting revolution of 2020 was tantamount to pouring gas on an existing flame. Then the remote work revolution began. Legacy AD’s limitations severely limit its ability to support hybrid operating architectures. This requires that domain-joined computers have a site line to the domain controller. This makes it impossible for employees to log into the corporate network when working from a remote workplace, such as a home office or hotel room. The only way to achieve AD connectivity is through a VPN connection. This complicates the process of adapting to a new computer at best. Moreover, your VPN infrastructure can quickly become a bottleneck if many users are using it. In this case, the VPN requires a remote access and routing policy to maintain least privilege so that remote users cannot access the entire network.

The modern world of a full migration to Azure AD

If you’re a Windows administrator, you’re probably familiar with the concept of tombstone preservation, which helps restore accidentally deleted objects in AD. Azure AD is a way to permanently secure your on-premises AD servers. You no longer need to worry about AD sync or DNS scavenging. Everything now exists in the cloud, where users and Azure-connected computers go to authenticate. Azure-joined computers only need an Internet connection to authenticate, eliminating the need for AD connectivity. Suddenly, users can work from anywhere in the world without the hassle of a VPN. Microsoft 365 uses Azure Active Directory (Azure AD) to manage user credentials, so employees are automatically signed in on their corporate devices.

The true beauty of Azure AD shines through in provisioning devices. Cloud domain-joined Windows PCs configured on Autopilot can be shipped directly from the original equipment manufacturer (OEM) to the waiting user, regardless of location. The user opens the box, turns on the device, and signs in using their Azure AD credentials. After Autopilot completes the device configuration process, Microsoft Endpoint Management, otherwise known as Intune, steps in to deliver all the assigned configuration settings, policies, and apps to that machine. After a couple of hours, the user is ready to start working. Assume the machine has a chipset that allows remote access to its BIOS and a technician to perform remote reboots even when the OS is down. In this case, you suddenly have a computer fleet that can be deployed, implemented and maintained without local support. Welcome to the hybrid world.

Not everyone can migrate directly to Azure AD

Moving your on-premises AD infrastructure to a native cloud is a pretty big step, but not everyone can do it right away. Some of the reasons include the following:

  • You still support Windows devices with older operating systems like Windows 7.
  • You rely on your existing imaging solution to deploy and configure devices you’re not ready to give up.
  • Some of your user devices have Win32 applications that rely on legacy AD machine authentication.

And finally, there’s Group Policy and Group Policy Options. Many enterprises have a large set of Group Policy Objects (GPOs) that they have created over the years to provide managed configuration and security settings for users and computers. The equivalent of Group Policy is an MDM provider such as Microsoft Endpoint Manager mentioned earlier. While MDMs can deliver settings configurations to computers regardless of location, the list of available settings is not as large as the combined set of GPs and GPPs. Although Microsoft has made great strides in closing the parity gap between the two, the difference between the two remains. For large enterprises that rely heavily on Group Policy, the lack of coverage of MDM settings may be enough to hold them back for now.

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Hybrid Azure AD-join as a temporary compromise

If you can’t make the jump to Azure AD right now, consider a third option called Hybrid Azure AD. Azure AD hybrid join preserves the legacy trusts your client machines have with on-prem AD while creating registered trusts in Azure AD. This double sign-on provides visibility to your device in the cloud so users can use single sign-on to access their Microsoft 365 apps. It also provides self-service password reset and Windows Hello PIN reset capabilities for your users regardless of location. You can create device-based conditional access policies that require devices to meet compliance requirements before they can access corporate resources to improve your security.

Like traditional AD, Hybrid Azure AD relies on Group Policy to centrally manage settings configurations, so the portfolio of Group Policy objects you’ve spent so much time building will still be in use. Unfortunately, Group Policy still relies on AD connectivity, and computers must be in line-of-sight to authenticate AD users who do not have cached credentials. You will also need to install Azure AD Connect on the on-premises server to synchronize data between on-premises AD and Azure AD so that users have the same credentials in both worlds. This means one more thing that your IT team will have to manage and support. Like anyone hybrid architectureit adds complexity to your network, which makes it harder to support.


Let’s say you’ve been browsing Microsoft’s certification portal for the past two years. In that case, you’ll notice that they no longer offer certification paths on their traditional operating systems and on-premises architectures. All about the cloud. While you may not be ready to make the leap yet, the day will come when you will be compelled to begin the migration to Azure AD to gain access to the latest technologies and innovative solutions. For some, joining Hybrid Azure AD may be the slow way to get there.

What Active Directory solution does your company use? Let us know further LinkedIn, facebook, and Twitter. We would love to hear from you!


https://www.spiceworks.com/tech/cloud/articles/legacy-ad-hybrid-ad-and-azure-ad-difference/ On-Prem AD vs. Hybrid Azure AD Join vs. Azure AD: Key Differences

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