Use ACS to Authenticate Users
Windows Azure Access Control Service (ACS) is a cloud service that provides user authentication and authorization for web applications and services. By using ACS, you do not have to factor authentication and authorization into your application code. Instead of implementing an authentication system with user accounts that are specific to your application, you can let ACS orchestrate the authentication and much of the authorization of your users. ACS integrates with standards-based identity providers, including enterprise directories such as Active Directory, and web identities such as Windows Live ID, Google, Yahoo!, and Facebook.
For Microsoft Dynamics NAV 2013 R2, use the following sequence of tasks to configure software and users to use ACS: