In older Nmap releases, what was the equivalent flag for performing a host discovery without port scanning (-sn)?

• A. -sL
• B. -sN
• C. -sP
• D. -sT

Answer: (C)

The concept being tested is how Nmap performs host discovery without doing any port scanning, and how the flags have changed over time. In older Nmap releases, the flag for a host discovery scan that only checks which hosts are up was -sP, a Ping Scan. This option targeted reachability (via ICMP, ARP, etc.) and did not proceed to port scanning. In newer versions, -sn serves the same purpose: it disables port scanning and focuses on identifying live hosts.

The other options represent different kinds of scans and do not equate to host discovery only. For example, -sT is a TCP connect scan (full port scan), -sN is a TCP null scan, and -sL just lists targets without scanning. Hence, -sP is the correct historical equivalent for host discovery without port scanning.