in my project, everything thing was was configured with LDAP.No need of user name and password to login for end users
issue : when a particular user is trying go to portal, its going to portal with out prompting password. But when he clicks one role assume as ESS it is asking for a user name and password
it is the issue of only one user and only for one particular role and other roles he can see with out password.
what may be missing for the user