Microsoft Certified: Identity and Access Administrator AssociateImplement an authentication and access management solutionEasy

A client is migrating their on-premises Active Directory Domain Services (AD DS) to a hybrid identity solution with Azure Active Directory (Azure AD). They want to ensure that users continue to authenticate using their existing on-premises credentials for applications integrated with Azure AD, without storing password hashes in Azure AD. Which authentication method should be implemented?

  1. AFederation with Active Directory Federation Services (AD FS)
  2. BAzure AD Kerberos authentication
  3. CPass-through Authentication (PTA)
  4. DPassword Hash Synchronization (PHS)
Show answer & explanation

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

Pass-through Authentication (PTA) allows users to sign in to both on-premises and cloud applications using the same passwords. It achieves this by validating users' passwords directly against their on-premises Active Directory, without storing password hashes in Azure AD.

Why the other options are wrong

  • A. Federation with AD FS also uses on-premises authentication but involves a more complex infrastructure with AD FS servers, which is not the simplest method for this specific requirement.
  • B. Azure AD Kerberos authentication is not a standard authentication method for hybrid identity solutions as described; Kerberos is primarily for on-premises AD.
  • D. PHS synchronizes a hash of the user's password to Azure AD, which violates the requirement of not storing password hashes in Azure AD.

Azure AD Pass-through Authentication (PTA)

An Azure AD Connect authentication method that signs users in by validating their passwords directly against on-premises Active Directory.

  • No password hashes stored in Azure AD.
  • Requires lightweight agents on-premises.
  • Provides a simple way to achieve hybrid identity.

Memory trick: PHS hashes, PTA passes, AD FS federates, Kerberos stays home.

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