Which deployment method for IPS/IDS is recommended for optimizing their effectiveness in a network with multiple security zones?

Deploying the IPS/IDS devices in inline mode at the network perimeter is considered the optimal method for ensuring comprehensive security across multiple security zones. This approach allows the intrusion prevention or detection system to monitor all incoming and outgoing traffic right at the boundary of the network. By being positioned at the network perimeter, the device can analyze traffic in real time and take immediate action against potential threats before they can penetrate further into the internal network.

In multiple security zones, the effectiveness of an IPS/IDS is significantly enhanced as it can enforce security policies consistently across the entire network landscape, providing a centralized point for traffic inspection and threat mitigation. This inline deployment configures the system to actively prevent attacks by dropping malicious packets, thereby increasing the security posture of the network significantly.

In contrast, placing the IPS/IDS behind the firewall may limit its effectiveness since it would only analyze traffic that has already passed the firewall's security checks, potentially allowing certain known threats to enter the network. Furthermore, using an active-passive deployment strategy may introduce delays in response times as one device is on standby, while installing the devices only within the cloud management layer could restrict visibility and control to just that environment, leaving other crucial zones unmonitored.