| 摘要 |
The present invention prevents all filter rules from leaking out and prevents the filter function of an entire network from stopping even when a problem occurs in a filter apparatus or the like that performs filtering. Provided is a filtering system provided with a plurality of apparatuses for filtering communication data on the basis of filter rules and a management device for managing the filter rules. When a first apparatus connected to an external network without being routed via the other apparatuses enters a prescribed state, distributed filter rules that are set in the first apparatus are restored by the management device on the basis of a plurality of distributed filter rules received from a plurality of second apparatuses connected to the external network via the first apparatus, and the distributed filter rules thus restored are set in the plurality of second apparatuses, the distributed filter rules being distributed such that the filter rules can be restored without using all of the distributed filter rules. |
