Which tool is used to scan for open ports on a target host?

• A. netstat
• B. ping
• C. traceroute
• D. nmap

Answer: (D)

Port scanning is the process of identifying open ports on a target host to see which services might be reachable. The best tool for this is Nmap because it’s purpose-built to scan a host for open ports, report which ports are listening, and often identify the services and versions running on those ports. It supports multiple scan techniques (like TCP SYN, connect, and UDP) to determine port state efficiently and can produce a detailed port/service map. Netstat is a local diagnostic that lists active connections and listening ports on the machine you’re on, not a remote scan. Ping checks whether a host is reachable, not which ports are open. Traceroute reveals the path to a host, not the port status. So Nmap is the appropriate choice for scanning open ports on a target host.