If NetStorage users are not LUM-enabled and they belong to a context that is not added to the search context list, then the full DN must be provided for login. For example, if a user named Bob has a DN of cn=Bob,ou=Accounts,o=Company, then he must specify his full DN while logging in. However, Bob can log in with his user name alone if ou=Accounts, o=Company is added as a search context or if Bob is LUM-enabled.
For more information about making the user LUM-enabled, see Section 8.3, Unable to View and Modify Files Properties, and for more information about adding users to the search context list, Section 7.2.1, Authentication Domains.