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

    Default:  0.0.0.0                Value:  IP address

    The IP interface (identified by the address) where the SAP
    entity will listen.  The default of 0.0.0.0 specifies that the
    SAP should listen on any available IP interface.

    You may choose to create one or more SAP entities to listen on
    specific IP interfaces.  However, if multiple SAP entities are
    in use, then none of them can use the local ip address of
    0.0.0.0.