Host: the machine on which ALI LDAP has been installed
Base: ou=users,dc=bea,dc=com - this is the base where all groups and users are stored
User DN: uid=administrator,ou=users,dc=bea,dc=com
For 'uid' I used administrator, but you can use another account from the portal. Knowing this you can for example implement authentication from external application against the portal, which are not working in portal context!