For convenience, we have configured the JDBC
UserDetailsService and hardcoded the Kerberos user IDs. Usually when configuring Kerberos authentication (especially with Active Directory), the user details will be retrieved from AD via LDAP. We'll walk through a typical configuration of an LDAP
UserDetailsService against Microsoft AD when using Kerberos authentication. We'll skip much of the explanation of Spring Security's integration with LDAP, although you're welcome to jump back to Chapter 9, LDAP Directory Services where we covered LDAP in great detail, including some specific suggestions about integration with AD via LDAP.
We can configure the authentication provider to reference an LDAP