Method of preserving symmetrical routing in a communication system based upon a server farm

A method of preserving symmetrical routing in a communication system comprising a server farm connected to the Internet network by an Internet front-end including at least an Internet access router IAR, said server farm comprising at least two customer cabinets with each customer cabinet including at least a WEB server and server farm resources enabling users connected to the Internet to access the WEB servers in said customer cabinets, and at least two firewalls for controlling communication between users and one of said WEB servers, said firewalls using a Virtual Router Redundancy Protocol (VRRP) to set up a primary firewall which owns the primary link of the VRRP group of links to at least one customer server and through which is established communication from said customer server and an Internet user, and said IAR selecting a firewall to be used in any communication from an Internet user to any one of said Internet users as being the firewall corresponding to the link having the lowest weight in a routing table;

• said method comprising the step of automatically generating a cost assigned to each interface associated with a firewall, at an initial time, according to a priority assigned by the VRRP protocol to said interface associated with said firewall.