/sys$common/syshlp/helplib.hlb Sys Parameters, LGI_HID_TIM  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    LGI_HID_TIM specifies the number of seconds that evasive action
    persists following the detection of a possible break-in attempt.
    The system refuses to allow any logins during this period, even
    if a valid user name and password are specified.

    LGI_HID_TIM is a DYNAMIC parameter.