312-50V9 · Question #490
Which NMAP command combination would let a tester scan every TCP port from a class C network that is blocking ICMP with fingerprinting and service detection?
The correct answer is B. NMAP -P0 -A -O -p1-65535 192.168.0/24. Scanning a class C network with ICMP blocked requires skipping ping discovery, specifying all 65535 ports, and enabling OS and service fingerprinting.
Question
Which NMAP command combination would let a tester scan every TCP port from a class C network that is blocking ICMP with fingerprinting and service detection?
Options
- ANMAP -PN -A -O -sS 192.168.2.0/24
- BNMAP -P0 -A -O -p1-65535 192.168.0/24
- CNMAP -P0 -A -sT -p0-65535 192.168.0/16
- DNMAP -PN -O -sS -p 1-1024 192.168.0/8
How the community answered
(27 responses)- A7% (2)
- B78% (21)
- C4% (1)
- D11% (3)
Why each option
Scanning a class C network with ICMP blocked requires skipping ping discovery, specifying all 65535 ports, and enabling OS and service fingerprinting.
This option omits a port range argument, so NMAP defaults to scanning only the top 1000 ports rather than all 65535 TCP ports as required.
The -P0 flag disables ICMP-based host discovery, which is required when the target network blocks ICMP echo requests. The -A flag enables aggressive mode, combining service version detection, OS fingerprinting, script scanning, and traceroute. The -p1-65535 argument explicitly targets all TCP ports, and the /24 CIDR notation correctly designates a class C network scope.
The /16 CIDR notation targets a class B network spanning 65536 hosts rather than a single class C /24 subnet, making the scope incorrect.
The -p 1-1024 argument restricts scanning to only privileged ports, not all 65535 TCP ports, and /8 targets an entire class A address space.
Concept tested: NMAP flags for full TCP port scan bypassing ICMP filtering
Source: https://nmap.org/book/man.html
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