| 摘要 |
PROBLEM TO BE SOLVED: To provide a fire wall system which can be installed with low resource and has a function not excessive IP-PBX or the like. SOLUTION: This fire wall system has a filtering means for filtering a packet, a packet from an IP network to a system to be protected, conforming to a protocol for dynamically providing a port. The filtering means has an authenticating means for authenticating the correctness of a protocol of a received packet, depending on whether or not at least the structure of a payload is a predetermined structure when a port number of the received packet from the IP network side is inhibited from being transferred; a discarding unit for discarding the received packet if the rightness cannot be authenticated; and a rightness-authenticated time processing unit for transmitting the received packet to the system to be protected, and changing the port number to be transfer-permitted when the rightness have been authenticated. COPYRIGHT: (C)2006,JPO&NCIPI
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