Final answer:
Port scanning software searches for open ports to identify accessible entry points on a node, used for both security auditing and by hackers.
Step-by-step explanation:
Port scanning software is used to search a node for open ports. This type of software functions by sending requests to connect to various ports on a computer and recording which ports respond or appear accessible. These tools are often utilized by network administrators for security auditing and by hackers for identifying potential entry points into a system. One of the most popular port scanning tools is Nmap, which is capable of identifying devices running on a network, discovering open ports, and determining what software and version are running on discovered devices.