Library /sys$common/syshlp/mailhelp.hlb SET-SHOW, FORWARD, Qualifiers, /ALL  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    The /ALL qualifier lists forwarding information or displays a
    message if the specified user does not have forwarding enabled.
    You must have SYSNAM privilege to use the /ALL qualifier. The
    /ALL qualifier is valid only when used with the /USER qualifier.