A firewall cluster having three or more firewall processing nodes sharing the same shared IP address. Port numbers are assigned to the firewall processing nodes within the cluster and are used to distinguish between traffic sent to the cluster. Each network connection is assigned a destination port number. Each node receives the network connection and its assigned port number and determines if the assigned destination port number matches one of its assigned port numbers. If so, the node processes the network connection. If the assigned destination port number does not match one of its assigned port numbers, the network connection is discarded.