Why does using the -n option speed up Nmap scans?

• A. It enables OS fingerprinting
• B. It reads targets from a file
• C. It avoids DNS lookups that can be slow
• D. It disables traceroute

Answer: (C)

The main idea being tested is how DNS resolution adds latency to scans and how skipping that step speeds things up. The -n option tells Nmap to never perform DNS resolution. By default, Nmap may query DNS to map IPs to hostnames (and possibly resolve provided hostnames to IPs) as it processes targets. Those DNS lookups can introduce noticeable delays, especially when scanning many hosts or when the DNS infrastructure is slow or unreachable. Skipping DNS resolution eliminates those round-trips, allowing Nmap to proceed directly with the scan using the IPs it already has, which speeds up the overall process. The other options don’t affect DNS resolution, so they don’t contribute to faster scans in the same way.