Which of the following technologies is used to detect unauthorized attempts to access and manipulate computer systems locally or through the Internet or an intranet?

An IDS continuously monitors network traffic and system events for signs of unauthorized access, policy violations, or malicious activity, alerting administrators when suspicious behavior is detected - this detection of intrusion attempts is its core and defining purpose, whether the source is local, Internet-based, or intranet-based.

A firewall enforces access control rules to block or allow traffic at network boundaries but does not analyze or alert on intrusion attempts the way an IDS does.

A DMZ is a network architecture segment that isolates public-facing servers from the internal network; it is a topology concept, not a detection technology.

Packet filtering is a technique used by firewalls to permit or deny packets based on header attributes such as IP address and port; it does not detect or report unauthorized access attempts.