Patent ID: 8341719

Claim:
A method of transmitting data packets from an external network to a secure network, the method comprising: interconnecting the secure network and the external network via a firewall, providing said firewall with a first interface with the external network and with a second interface with the secure network, providing, by said firewall, over said second interface, a plurality of virtual interfaces, storing, in said firewall, associations between items of specific information of the firewall and said virtual interfaces, storing in said secure network, associations between items of specific information of the firewall and said virtual interfaces, connecting the second interface of the firewall to a router of the secure network, and: a) determining, by the firewall, whether to authorize the transmission of a packet received from the external network to the secure network on the basis of predefined security criteria, the received packet comprising source and destination IP addresses and source and destination ports; b) if the received packet is authorized, selecting, by the firewall, an item of specific information to be communicated to the secure network by way of the unmodified contents of the authorized packet, wherein an association between the selected item of specific information and a virtual interface is stored in the firewall and in the secure network; c) determining, by the firewall, said virtual interface from said plurality of virtual interfaces, as a function of the item of specific information selected on the basis of said association; d) transmitting, by the firewall, the unmodified authorized packet via the determined virtual interface; e) on reception of the unmodified authorized packet in the secure network, deducing, by said router of the secure network, said item of specific information from the virtual interface through which the unmodified authorized packet is received, on the basis of said association; and f) routing by said router, the unmodified authorized packet as a function notably of the item of specific information deduced in step e).