Virtual private network (VPN) implementation method in transparent mode and security equipment

The invention discloses a virtual private network (VPN) implementation method in a transparent mode and security equipment. The security equipment in a transparent transmission mode creates a three-layer logic port used for establishing a VPN tunnel with opposite-end equipment; the security equipment processes a first message sent by the intranet equipment to the opposite terminal equipment based on the binding relationship between the three-layer logic port and the intranet interface of the security equipment; and the security equipment updates the destination MAC address of a second message sent by the opposite terminal equipment to the intranet equipment based on the three-layer logic port. According to the mode, under the condition that existing network planning of a user is not changed, the safety equipment can be deployed in the network in a transparent transmission mode, and furthermore, a three-layer logic port can be created in the safety equipment, so that VPN communication between intranet equipmen