Authorization methods: Microsoft's implementation of Open Authorization (OAuth)
Conditional access policies: Mobile Application Management (MAM) and Azure Active Directory (Azure AD) Conditional Access
Very simplistic we can say, that with modern authentication, the client is talking to the service and getting redirected to Azure AD for authentication with the username and password or other methods like MFA.
How to set up
To activate the Modern Authentication for a new Email Account on XCALLY using Office365 as provider, you need to:
A. Register an application in the Azure Portal, so the Microsoft identity platform can provide authentication and authorization services for your application and its users.
B. Configure a new Cloud Provider on XCALLY by choosing Microsoft Azure as a service and Outlook365 as the type.
C. Associate the Cloud Provider with the email accounts on XCALLY.
Azure AD application registration
Registering your application establishes a trust relationship between your app and the Microsoft identity platform. The trust is unidirectional: your app trusts the Microsoft identity platform, and not the other way around.
Follow these steps to create the app registration:
If you have access to multiple tenants, use theDirectories + subscriptionsfilterin the top menu to switch to the tenant in which you want to register the application.
Enter a displayNamefor your application. Users of your application might see the display name when they use the app, for example during sign-in. You can change the display name at any time and multiple app registrations can share the same name. The app registration's automatically generated Application (client) ID, not its display name, uniquely identifies your app within the identity platform.
Specify who can use the application, sometimes called itssign-in audience.
Supported account types
Description
Accounts in this organizational directory only
Select this option if you're building an application for use only by users (or guests) inyourtenant. Often called aline-of-business(LOB) application, this app is asingle-tenantapplication in the Microsoft identity platform.
Accounts in any organizational directory
Select this option if you want users inanyAzure Active Directory (Azure AD) tenant to be able to use your application. This option is appropriate if, for example, you're building a software-as-a-service (SaaS) application that you intend to provide to multiple organizations. This type of app is known as amultitenantapplication in the Microsoft identity platform.
Accounts in any organizational directory and personal Microsoft accounts
Select this option to target the widest set of customers. By selecting this option, you're registering amultitenantapplication that can also support users who have personalMicrosoft accounts.
Don't enter anything forRedirect URI (optional). You'll configure a redirect URI in the next section.
SelectRegisterto complete the initial app registration.
When registration finishes, the Azure portal displays the app registration'sOverviewpane. You see theApplication (client) ID. Also called theclient ID, this value uniquely identifies your application in the Microsoft identity platform.
Your application's code, or more typically an authentication library used in your application, also uses the client ID. The ID is used as part of validating the security tokens it receives from the identity platform.