What happens to Nmap scanning speed when using the -F flag?

• A. Scanning becomes slower due to more ports being scanned
• B. Scanning speed is unchanged
• C. It disables port scanning
• D. Scanning becomes faster due to fewer ports being scanned

Answer: (D)

Using the -F option makes Nmap run in fast mode by limiting the scan to the top 100 most commonly used ports. Since only a small subset of ports is checked, the total number of probes drops dramatically, so the scan completes much faster. The trade-off is that services on ports outside that top-100 list might be missed, giving a less complete view of open ports. So the faster speed comes from scanning fewer ports, not from scanning more or disabling scanning.