This update addresses the "Kerberos Interoperability - New Realms are not Propogated Properly" issue in Windows 2000. Kerberos is an authentication protocol that allows individuals to exchange private information across an otherwise open network. Installing this update allows a Kerberos realm to propogate correctly to client computers when this realm is added to the server's realm list.
For additional information about this issue, read Microsoft Knowledge Base (KB) article Q253531. (This site is in English.)
For information on Kerberos and Windows 2000, read the Windows 2000 Kerberos Authentication White Paper. (This site is in English.)