Complete guide to joining teams to Azure AD and Microsoft Entra ID

If you work with Windows 10 or Windows 11 and are considering Join your teams to Azure AD or Microsoft Sign In IDYou've probably realized that it's not just a matter of "clicking next and accepting everything." Behind the scenes, there are decisions regarding authentication, synchronization with local Active Directory, security, remote access, and a few other things that are important to understand to avoid problems in production.

In this guide we'll see, step by step and without beating around the bush, How to join teams to Azure AD and Azure AD Domain ServicesThis article will cover what options you have if you're coming from a traditional Active Directory, how Microsoft Entra Connect fits into all of this, and what best practices for security, high availability, and performance you should implement. The goal is for you to finish reading this article with a comprehensive and practical overview, whether you're just looking to connect a few laptops to the cloud or you're planning a serious hybrid architecture.

What is Azure AD / Microsoft Entra ID and how does it differ from classic AD?

Before touching anything in production, it's worth remembering that Azure AD (now Microsoft Entra ID) is not the same as classic Active Directory Domain ServicesAlthough both manage identities, they function differently and are used for different scenarios.

Microsoft Entra ID, on the other hand, is a fully cloud-based identity and directory serviceIt is not configured with GPOs or accessed with LDAP; it is geared towards modern authentication (OAuth, OpenID Connect, SAML), login to SaaS applications, conditional access control and device management for modern and remote work.

Within this ecosystem, the following also come into play Azure AD Domain Services (AAD DS)Azure Domain Services (LDAP) is a managed service that provides domain functionalities (LDAP, Kerberos, domain join) in Azure without requiring you to deploy your own domain controllers. It is especially useful for virtual machines in Azure that They need to join a domain.But you don't want to maintain a full AD.

User types and available authentication methods

In your organization you can have Users created directly in Microsoft Login ID (the famous "cloud" users) and users that sync from your local Active Directory using Microsoft Entra Connect. Understanding this is key, because it determines the authentication method and how computers will join the directory.

Microsoft Entra ID supports multiple authentication methodsEach one has its pros and cons, and it's wise to choose them carefully based on your security policies and infrastructure.

Cloud authentication

In this mode, Credential validation is done directly in Microsoft Entra IDIn other words, the user authenticates in the cloud, without having to connect to your local network. Within cloud authentication, there are two main variations:

• Password Hash Synchronization (PHS)An additional password hash is synchronized from the local Active Directory to Microsoft Entra. Users can log in to the cloud with the same password they use locally, but the actual authentication is resolved by the Microsoft Entra ID. This is the simplest option and is usually recommended unless there are very strong security restrictions.
• Pass-through authentication (PTA)Credentials are validated in your local environment using PTA agents installed on on-premises servers. Microsoft Entra doesn't store the password hash required for authentication; instead, it forwards the request to the on-premises agent, which validates it against the local Active Directory. This is useful when security policies prohibit synchronizing password hashes to the cloud.

Federated authentication

In federated authentication, Microsoft Entra delegates authentication to a trusted external systemsuch as AD FS (Active Directory Federation Services) or other federation providers. This system issues security tokens and enables advanced integrations, complex SSO, or very specific compliance requirements.

This approach is more complex to implement and maintain, but it can fit large organizations that already have a federation infrastructure in place and they don't want to change the authentication model they've been using for years.

Joining devices to Microsoft Sign In ID: basics

When we talk about joining teams to Azure AD or Microsoft Entra ID, we mean that Windows 10/11 devices become “Azure AD joined devices”This is not exactly the same as joining them to a classic domain, although the practical effect (login with a corporate account) is quite similar.

A device joined to Azure AD allows you to log in with an organizational account Enter Microsoft tenant ID and apply policies to it conditional accesscompliance, MFA, etc. Furthermore, it integrates well with solutions like Intune for centralized configuration and application management.

For this to work, the service of Microsoft device registration Login It must be properly configured, and your user account must have permission to join devices. You should also keep an eye on the device limit per user, as there is a configurable maximum that shouldn't be ignored.

If you want to check afterwards if a team It is already connected to Azure AD, you can go to “Access to work or school"and check the status: your organization's directory and the device should appear as connected to the tenant."

Allow users to link devices to Microsoft Sign In ID

One of the steps that many people overlook is that, by default, Not all users can join teams to Microsoft. Log in however you want.This capability is controlled from the Azure portal and should be adjusted to fit your management model.

To configure who can join devices, you must go into the Azure portal with directory administrator permissions and follow a very specific path within Microsoft Enter ID to the device options and their configuration.

The usual process is as follows: on the portal, you enter “Microsoft Sign In ID”, then in the section of Devices Within the administration menu, you then access "Device settings". There you will see the option "Users can join devices to Microsoft Sign In…", which is the one that makes the difference.

That option can be set to “All” or “Selected”If you choose "Everyone," any user in the tenant can join computers to a Microsoft Entra ID. If you choose "Selected," only the members (users or groups) you specify will be able to do so, which is usually more reasonable in medium and large environments.

To add users or groups, click the "Selected" link, use the "Add" button, and choose the users and groups from the list who will have permission to join devices. When you're finished, confirm with "Select" and "OK," and don't forget to click. “Save” on the device screen so that the change can truly be implemented.

Windows Autopilot and user-controlled joining

In modern mass deployment scenarios, especially with laptops shipped directly to the user, Windows Autopilot It's a key component. One of its most commonly used modes is the combination of "user-controlled Microsoft login," which greatly simplifies the initial device setup.

In this flow, the end user, upon turning on the new or reset device, An assistant follows, eventually joining the team to Microsoft. Enter and, typically, by registering it in Intune for management. The IT department doesn't need to physically touch the machine, provided it has been previously registered as an Autopilot device.

In order to use Autopilot with this type of connection, the essential condition is that Users are allowed to join devices to Microsoft Sign In IDas we explained earlier. Otherwise, the process will crash halfway through and the configuration will have to be redone.

The next step in a well-organized deployment would be the registering devices such as Windows Autopilotassign deployment profiles, configure Intune policies, and get everything ready so the user only has to turn on the PC, connect to the internet, and authenticate with their corporate account.

Integrate on-premises Active Directory with Microsoft Entra ID

When you have an on-premises Active Directory environment and want to leverage Azure AD, the most common approach is to set up a hybrid architecture of identitiesIn this architecture, your on-premises Active Directory remains the primary source of identities, but these are synchronized with Microsoft Entra ID so they can be used in the cloud.

The centerpiece of that integration is Microsoft Entra Connect (formerly Azure AD Connect), which is installed on a local server or virtual machine and is responsible for copying information about users, groups, and other objects from the local AD to Microsoft Entra ID.

With Entra Connect you choose which domains, organizational units or groups to synchronize, which attributes are copied to the cloud and how frequently the synchronization cycles run. You also define the authentication method (PHS, PTA, federation) and, if applicable, single sign-on.

This reference architecture typically involves several elements: a Microsoft tenant Log in that receives the data, one or more on-premises AD DS domains acting as the source, a Microsoft Entra Connect server for synchronization, and, if your application requires it, additional virtual machines in Azure for n-tier web applications that use Entra ID as the identity provider.

Topologies supported by Microsoft Entra Connect

One of the strengths of Microsoft Enter Connect is that It supports various synchronization topologiesdesigned to adapt to organizations with one or more forests, and even with multiple Microsoft Enter directories.

The simplest topology is that of Single forest with a single Microsoft directory. EnterIn this case, one or more domains within the same forest are synchronized with a single Microsoft Entra ID tenant. This is the most common option and the one created by default with the express installation.

If you have a more complex business, you might work with several forests in localIn this scenario, a single Microsoft Entra directory can still be used, consolidating identities across all forests and preventing duplicates through filtering and appropriate configuration. This way, each user is represented only once in the cloud, even if they exist in multiple forests.

Some organizations need to maintain separate forests but share the same Microsoft Entra ID; this configuration is known as several forests with independent topologiesThe idea is to treat each forest as an isolated entity, even though they all synchronize against the same directory in the cloud.

Another interesting pattern is the use of a temporary server or the secondary Microsoft Entra Connect Sync, which operates in staging mode. This server imports and processes data, but does not upload it to Microsoft Entra until that mode is disabled. It is very useful for introducing configuration changes, testing them, or ensuring high availability of the solution.

Object filtering and synchronization settings

By default, Microsoft Enter Connect synchronizes only the objects that meet a set of rules Preconfigured rules for users, groups, contacts, teams, and other object types. These rules can be reviewed and adjusted using the Sync Rules Editor.

User objects, for example, must have a attribute sourceAnchor unique and the accountEnabled attribute filled in to be candidates for synchronization. In addition, they must have a valid sAMAccountName and cannot begin with reserved strings such as “Azure AD_” or “MSOL_”.

If you don't want to sync your entire local directory as is, you can apply filtered by domains, organizational units, groups, or specific attributesFor example, you could exclude inactive accounts, test OUs, or users who don't need access to cloud resources.

Filtering by attributes lets you create more elaborate rules, such as "synchronize only objects from this domain that have this specific value for this attribute." This helps clean data and reduce the attack surface in Microsoft Entra ID.

If you have multiple Microsoft Entra directories, it is essential Ensure that each object in the local forest is synchronized to only one directoryTo avoid write conflicts and problems with delayed password writes, independent Entra Connect servers and filtering that leaves mutually exclusive sets of objects are used.

Login method and user experience

When you install Microsoft Enter Connect using the quick setup, it is usually enabled password hash synchronization as the default login method. This allows users to use the same password in the cloud as they do locally, for a very seamless experience.

However, it's not always the best option. If your security policy expressly prohibits it, then it's not the best choice. synchronize password hashes to the cloudYou should seriously consider pass-through authentication (PTA), which keeps all password validation in your on-premises environment.

Another important factor is single sign-on, or SSO. In many environments, the goal is for users connecting from domain-joined machines on the corporate network, so you don't have to type in your credentials over and over again to access cloud resources. This can be achieved with Microsoft Entra Connect's SSO options or through federation with AD FS.

If you already have AD FS or other deployed identity providerIt may make sense to integrate it with Microsoft Entra ID to leverage that authentication infrastructure and maintain a consistent login experience across on-premises and SaaS applications.

Using the Microsoft Application Proxy Login

In addition to team union and authentication, Microsoft Entra ID offers you the application proxywhich is used to publish local web applications to the internet without having to open classic inbound ports in the firewall.

The idea is to install an application proxy connector on your internal network, which Open a secure outbound connection to Microsoft. Log inRequests from remote users arrive in the cloud, are validated with the Entra ID directory and, through that connector, are forwarded to the local web application.

This helps you reduce the exposed attack surfaceCentralize access control using Entra policies (including MFA and conditional access) and provide a more integrated experience for users who are already authenticated with their corporate identity in the cloud.

Monitoring and high availability in Microsoft Entra Connect

For this whole setup to work in the long term, you need monitor the synchronization status and ensure that, if something breaks, you can recover without losing identity service.

Microsoft Enter Connect installs a Connect Health agent which gathers information about performance and synchronization errors. From the Azure portal, in the Connect Health section, you can view alerts, graphs, and technical details to detect problems early.

In addition to the synchronization agent, there is the Connect Health agent for AD DSThis tool is installed within the local domain to monitor the health of domain controllers and detect issues with directory services. Similarly, the Connect Health agent for AD FS helps you monitor your federation infrastructure if you have it deployed.

Regarding high availability, a good practice is Deploy a second instance of Microsoft Enter Connect Sync in staging modewhich serves as a fallback server. This instance maintains its own synchronization database, but does not write to Microsoft Enter until you disable staging mode, at which point it can assume the primary role.

If you decide not to use the default LocalDB database and opt for a Dedicated SQL ServerYou can increase availability by using SQL clusters. Some features, such as classic mirroring or AlwaysOn, are not supported, so it's advisable to carefully review the documentation before designing your solution.

Security, conditional access, and identity protection

Following good security practices in Microsoft Entra ID is non-negotiable. Identities are the new perimeter, so you have to protect logins and access to resources with a risk and context approach.

You can also use the type of device and its compliance status As part of the decision: a managed and encrypted corporate device is not the same as an uncontrolled personal PC. Entra ID allows you to consider the platform (Windows, iOS, Android, etc.) and whether the device is enabled or not.

Microsoft Entra ID P2 editions include Identity ProtectionIt uses advanced algorithms to detect risky activities, such as logins from unusual locations, IP addresses flagged as suspicious, or compromised devices. This information can then be used to generate alerts and apply risk-based access policies.

Another piece that shouldn't be forgotten is the password managementThe P1 and P2 editions allow for deferred password writes, enabling users to perform self-service password resets from the Azure portal, with the change being replicated to the on-premises Active Directory. Before enabling this feature, it's essential to thoroughly review your organization's password policy and restrict who can make changes and how.

Costs, performance and daily operation

Although many of these capabilities are included with the appropriate licenses, it is advisable review the cost impact and plan the correct sizing. The Azure pricing calculator can help you estimate costs based on the number of users, advanced features (P1/P2), application proxy usage, and more.

From a performance standpoint, the Microsoft Entra ID service geographically distributed using replicasA primary replica where writes are performed and several read-only replicas distributed around the world. Changes propagate gradually, allowing it to scale very well, since most operations are reads.

For the synchronization server, you need to get an idea of How many objects are you going to sync?If you have fewer than 100.000 objects, SQL Server Express LocalDB is generally sufficient. If you exceed that volume, a production SQL Server and a custom installation of Entra Connect pointing to that instance are recommended.

At an operational level, you will need to combine the management of Microsoft Login ID from the Azure portal with the maintenance of the Entra Connect servers. The Entra Connect console allows you to adjust synchronization settings, change the login method, enable or disable staging mode, and review certain basic parameters.

Furthermore, with tools such as Synchronization Service Manager You can review the details of synchronization operations, launch manual cycles, and manage connectors to different domains. The synchronization rules editor is used to customize attribute transformations, add new objects to synchronize, or further refine filtering.

Ultimately, joining teams to Azure AD and setting up a hybrid architecture with on-premises Active Directory is much more than just checking a box in Windows; it involves Design the identity model well, carefully choose the authentication method, control who can connect devices, and monitor security with conditional access and Identity Protection. and ensure that synchronization with Entra Connect is well-suited to your topology and capacity. If all of this is done thoughtfully, the result is a robust, flexible environment ready for modern work, both in the office and miles away.