During migration, for special users with user identifiers (UIDs) that are less than 20, Windows accounts are created such that the first nine characters of their Network Information Service (NIS) domain are appended to their UNIX user name to create a Windows logon name. Their UNIX user name is unaffected. For example, if you migrate root from physlab to Server for NIS, a new Windows user will be created called physlab_u_root. The UNIX user name is still root, and NIS queries from physlab domain will be unaffected.
A group called root from such a domain, if migrated, will create a group called physlab_g_root.