A packet transfer apparatus is provided with: storage means configured to store a predetermined search pattern and an address identifying a predetermined apparatus; determination means configured to determine whether predetermined data in a packet received from a network interface matches the search pattern; determination means configured to determine a network interface for outputting the packet using the determination result; replacement means configured to replace an address identifying a destination apparatus of the packet with an address identifying the predetermined apparatus when outputting the packet from a network interface connected to the predetermined apparatus; and packet sending means configured to send the packet to the determined network interface.