| 摘要 |
A network gateway apparatus is provided, which is able to add an encryption communication function that easily enhances security without forcing setting changes in an existing network environment. A process of "deceiving" the TCP/IP protocol stack 205 is performed In order to add a minimum requisite program for implementation of a XPTCP gateway apparatus 101, while utilizing a function of a TCP/IP protocol stack 205 to the utmost. A source MAC address, a source IP address, a source port number, a destination MAC address, a destination IP address and a destination port number are pre-written in a rewriting table in order that the TCP/IP protocol stack 205 is able to process a packet that should be unrelated to an IP address allocated to the XPTCP gateway apparatus 101. Then, a source MAC address and a source IP address written in a received packet are rewritten into a false MAC address and a false IP address, respectively, and a destination MAC address and a destination IP address are rewritten into an IP address and a MAC address allocated to the XPTCP gateway apparatus 101, and then the rewritten addresses are provided to the TCP/IP protocol stack 205. |
