Introduction to Windows Azure Active Directory Sync Tool
Windows Azure Active Directory sync tool is used to connect Azure AD with Windows Server AD or on-premises AD.
This tool has the following prerequisites:
- Windows Server 2008/2008 R2/2012/2012 R2
- .NET 4.5
- PowerShell (Preferably PS3 or better)
- The machine on which you are installing AAD Sync can be stand-alone, a member server, or a domain controller.
You can download the link from the following location:
More details and complete installation is shown in the following article on Microsoft TechNet.