If you want to speed up an Nmap scan by reducing the number of ports scanned, which option would you use?

• A. The -F flag
• B. The -T flag
• C. The -A flag
• D. The -sV flag

Answer: (A)

Speeding up a scan by reducing the number of ports scanned comes from using a fast mode that limits probe targets. The fast mode option makes Nmap check only the predefined set of the most common ports (about 100) instead of the full default list, dramatically cutting scan time. This is the best choice when you want quick results and are willing to miss services on less typical ports.

Other options change what or how much you detect rather than how many ports are checked: adjusting timing (-T) alters speed but not port count, enabling version detection (-sV) adds more probes for service versions, and aggressive scanning (-A) adds OS, script, and other checks.