CompTIA Network+ N10-009 Practice Question

The correct answer is nmap -O -sT 192.168.1.123. This command performs a TCP connect scan (-sT) along with operating system detection (-O). This scan type will identify all open ports and determine the operating system, providing essential security and network management information. nmap -p- 192.168.1.123 runs a scan for every port but lacks OS detection. nmap -F 192.168.1.123 performs a fast scan, checking fewer ports and without OS detection, which does not meet the requirement of checking all ports. nmap -sn 192.168.1.123 merely pings the host to check if it is up, without scanning any ports or detecting the operating system.