You might be familiar with DirSync. DirSync is a Microsoft-supplied tool for copying the local directory and then propagating the contents to Microsoft Azure for Azure Active Directory. It works with Office 365 and Azure AD. It works for single-forest scenarios and with a Forefront Identity Management (FIM) solution for multi-forest scenarios. However, configuring FIM takes expertise and time.
Microsoft has released the replacement for DirSync and eliminated the need for a FIM infrastructure in the Microsoft Azure Active Directory Sync Services (AAD Sync). AAD Sync simplifies the setup and makes synching easier. It also works with Azure Active Directory and Office 365, but supports both a single forest or multi forest on-premises Active Directory implementation in a single service.
AAD Sync provides the following improvements:
- Able to synchronize multi-forest Active Directory environments without needing the full blown features of Forefront Identity Manager 2010 R2.
- Provides for advanced provisioning, mapping and filtering rules for objects and attributes, including support for syncing a very minimal set of user attributes.
- Delivers configuration options for multiple on-premises Exchange organizations to map to a single AAD tenant.
Download it here: Microsoft Azure Active Directory Sync Services
Learn how to implement it here: Azure Active Directory Synchronization Services (AAD Sync)