Which technique is defined as sending transmissions to end nodes and analyzing responses to identify information about the communications system?

• A. Ping Sweep
• B. Traceroute
• C. Port Scanning
• D. Fingerprinting

Answer: (C)

This question is about discovering what services and open ports exist on hosts by sending probes and reading how the devices respond. Port scanning works by sending packets to a range of ports on a target machine and then analyzing the replies (or lack thereof). Each response or timeout tells you whether a port is open, closed, or filtered by a firewall, and sometimes reveals what service might be listening. This information helps map the target’s capabilities and potential entry points, which is exactly what this description is aiming at.

In contrast, ping sweeps focus on whether hosts are alive by sending simple ICMP echo requests and looking for replies, not on the services or ports available. Traceroute maps the path packets take to a destination, showing hops and delays rather than the target’s services. Fingerprinting aims to identify the operating system or specific service versions from response patterns, which is more about identification than broad port/service discovery.