What does the -Pn option do, and when would you use it?

• A. -Pn tells Nmap to skip host discovery and treat all targets as online; use when ICMP is blocked or you know hosts are up.
• B. -Pn enables DNS resolution for all hosts.
• C. -Pn performs a ping sweep to identify live hosts.
• D. -Pn saves outputs in multiple formats.

Answer: (A)

Host discovery is the step where Nmap checks which targets are actually online before starting a scan. The -Pn option disables that check and makes Nmap treat every specified target as online, proceeding straight to the port scan. You’d use it when discovery probes (like ICMP ping) are blocked by a firewall or when you already know the hosts are up and want to scan them regardless of their responsiveness. The benefit is that you won’t be blocked by discovery failures, but the trade-off is potential waste time and network traffic on hosts that aren’t actually up.