IP address translator and packet transfer apparatus

摘要

An IP address translator comprising: SIP-ALG message processing unit for assigning a virtual IP address in a process of establishing a session between an IPv4 apparatus and an IPv6 apparatus via a SIP server; an address translation table for storing a relation between an IPv4 address and a virtual IPv6 address, a relation between an IPv6 address and a virtual IPv4 address, and filter information in association with each of the virtual addresses; and a processor for performing address translation on the IPv4 and IPv6 packets according to the address translation table, wherein header information of received packets is checked on the basis of the filter information before the address translation to discard a packet which does not adapt to the filter information.