In SharePoint 2013, when you create a web application in
Central Administration, you can only specify authentication types and methods
for claims-based authentication. In previous versions of SharePoint, you could
also configure classic mode authentication for web applications in Central
Administration. Classic mode authentication uses Windows authentication and
SharePoint 2013 treats the user accounts as AD DS accounts. Read blog post about
Classic mode authentication in SharePoint 2013:
http://www.dshift.com/blog/classic-mode-authentication-in-sharepoint-2013/