Library /sys$common/syshlp/nclhelp.hlb set, dtss, courier_role  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Specifies a server's interaction with the set of global servers.

    backup courier   The local server becomes a courier if none are
                     available on the LAN.

    courier          The local server synchronizes with the global set
                     of servers.

    noncourier       The local server does not routinely synchronize
                     with the global set of servers.  This is the
                     default.