Microsoft Certified: Azure Solutions Architect ExpertDesign identity, governance, and monitoring solutionsEasy

A multinational corporation is migrating its on-premises applications to Azure. They require a centralized identity solution that allows users to sign in once with their existing on-premises Active Directory credentials and access both on-premises and Azure-based applications seamlessly. The solution must minimize infrastructure overhead in Azure and avoid synchronizing password hashes to the cloud. Which authentication method should be implemented?

  1. AAzure Active Directory Domain Services (AAD DS)
  2. BPass-through Authentication (PTA)
  3. CPassword Hash Synchronization (PHS)
  4. DFederation with Active Directory Federation Services (AD FS)
Show answer & explanation

Correct answer: B. Pass-through Authentication (PTA)

Pass-through Authentication (PTA) allows users to sign in to Azure AD using their on-premises Active Directory passwords without synchronizing password hashes to Azure AD. It uses lightweight agents on-premises to validate credentials.

Why the other options are wrong

  • A. AAD DS provides managed domain services in Azure but is not primarily an authentication method for syncing on-premises AD to Azure AD for user sign-in.
  • C. PHS synchronizes password hashes to Azure AD, which the company wants to avoid.
  • D. AD FS provides federation but typically involves significantly more infrastructure overhead than PTA and is more complex to manage.

Azure AD Pass-through Authentication (PTA)

Azure AD Pass-through Authentication allows users to sign in to both on-premises and cloud-based applications using the same passwords. It achieves this by validating users' passwords directly against their on-premises Active Directory.

  • No password hashes stored in Azure AD
  • Lightweight agents on-premises
  • Seamless single sign-on experience
  • Supports legacy authentication protocols

Memory trick: PTA Passes Through to AD.

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