Library /sys$common/syshlp/tcpip$ucp_help.hlb SET, ARP, Parameters  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 mac_address

    Required.

    Specifies the physical Ethernet or FFDI network address to be
    mapped to an IP address. Not valid with SET NOARP.

 host_name

    Optional.

    Specifies the host on which the targeted interface resides. If
    you do not supply a host name, you must supply its IP address.

 IP_address

    Optional.

    Specifies the 32-bit address that identifies the network and
    host. If you do not specify the host's IP address, you must
    specify its host name.

    You cannot use wildcards.