Which security technology inspects network traffic, attempting to find matches to suspected malicious or unauthorized activity based on the content of the packets, and is limited to being able to only log or send alerts on that malicious activity?

Intrusion Detection System (IDS)

Explanation:

An Intrustion Detection System (IDS) is an application software or hardware device that monitors network traffics or systems. It searches the network or system for threats. These threats could be (but not limited to) suspicious activities or malicious activities or policy violations.

Once a threat is observed, it beeps or alerts the system administrator(s). Also, all these threats are then logged in a security information and event management (SIEM) system.

But an IDS cannot block or prevent threats on the system.

1. entrepreneur.com

2. wikipedia