PIX Failover Feature

Since PIX OS v5.1, PIX models support stateful failover, allowing the system to maintain connection state information for the TCP connection during the failover from the primary unit to the standby unit. If failover occurs, the secondary unit assumes the IP and MAC addresses of the primary unit and begins accepting traffic. Because the other network devices don’t see any change in these addresses, no ARP entries change or timeouts occur anywhere in the network.