Which tool is a command-line network scanner for host discovery, port scanning, and version detection?

• A. Nessus
• B. Nmap - Asset Discovery
• C. Angry IP Scanner
• D. Core Impact

Answer: (B)

Nmap is designed as a command-line network scanner that can perform host discovery, port scanning, and service/version detection in a single workflow. For finding live hosts, you can use a host discovery sweep to determine which devices respond, then move on to scanning to see which ports are open on those hosts. With port scanning, Nmap probes specified ports (or a range) to reveal which services are listening. For version detection, Nmap probes the detected services to identify the running software and its versions, often using the -sV option. The combination of these capabilities, plus the ability to run a single pass that includes OS detection and scripting (via -A), makes Nmap the best fit when you need a fast, flexible, and scriptable tool for discovering hosts, ports, and service versions from the command line.

Nessus focuses on vulnerability assessment rather than pure network scanning and version discovery, often via a broader GUI-driven workflow. Angry IP Scanner is a lightweight, primarily GUI-based scanner with limited depth for version detection. Core Impact is a commercial pentest framework with broader exploitation features, not a focused command-line tool for host discovery and version detection.