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 through an Internet access router. The server farm includes at least two customer cabinets with at least a WEB server and at least two firewalls. The firewalls use a Virtual Router Redundancy Protocol (VRRP) to set up one firewall as being the primary firewall. The method includes checking in each firewall whether there is a change of the VRRP state from primary to secondary or reciprocally. Such a change indicates that a link between the primary firewall and one of the customer cabinets has failed. The link is disabled from the network to the firewall the state of which has changed from primary to secondary or the link is enabled from the Internet network to the firewall the state of which has changed from secondary to primary.