Abstract: An improper access prevention program is provided that executes processing for preventing improper access through a network, whereby the task load on the administrator can be alleviated and a plurality of sites protected by a plurality of protection means can be effectively and efficiently protected, and such improper access prevention program is designed to cause administration means connected to a plurality of protection means and a plurality of detection means through a network to receive improper access information detected by any of the detection means, to decide, in accordance with this received information, on protection means where counter-measures against this improper access are to be implemented and decide on the particulars of the protective counter-measures in respect of the protection means, and to give instructions for the implementation of said protective counter-measures that have been decided upon to the protection means.