A method of the Virtual Private Network (VPN) communication employed for a security gateway apparatus and the security gateway apparatus using the same, which allow a personal computer outside a local area network (LAN) to access, via a WAN, to a terminal on the LAN, virtually regarding the outside PC...http://www.google.com.hk/patents/US20010020273?utm_source=gb-gplus-share專利 US20010020273 - Method of virtual private network communication in security gateway apparatus and security gateway apparatus using the same
