In data centers like these, redundant routers, switches, and even power supplies help ensure business continuity during an outbreak. The IPS appliances, however, do not support stateful failover. IPS devices maintain state with traffic flows and may drop traffic from an asymmetrical traffic flow. It is therefore important to factor this into the design.
You can use the bypass mode as a diagnostic tool and a failover protection mechanism. You can set the sensor in a mode where all the IPS processing subsystems are bypassed and traffic is permitted to flow between the inline pairs directly. The bypass mode ensures that packets continue to flow through the sensor when the sensor's processes are temporarily stopped for upgrades or when the sensor's monitoring processes fail. There are three modes: on, off, and automatic. By default, bypass mode is set to automatic.
