Port scanning is a technique that an attacker uses to discover which network ports are open, closed, or filtered on a target device. By sending packets to different ports and observing the responses, an attacker can identify the services and applications running on the device, as well as potential vulnerabilities that can be exploited.
Port scanning is a common reconnaissance activity that precedes an attack. References: Understanding Cisco Cybersecurity Operations Fundamentals (CBROPS) - Cisco, page 2-6; 200-201 CBROPS - Cisco, exam topic
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