A security engineer is installing an IPS to block signature-based attacks in the environment. Which of the following modes will best accomplish this task?

An Intrusion Prevention System (IPS) in active mode is designed to detect and automatically block or prevent attacks, such as those identified by signatures. This directly accomplishes the task of blocking signature-based attacks. Monitor mode, also known as passive or promiscuous mode, only detects and alerts on threats without taking preventative action. Sensor mode is a component of an IPS that collects data but doesn't inherently define its operational blocking capability. Audit mode is typically used for logging and reviewing events, not for active blocking.