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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.

Scanning Networks

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)
  • A
    7% (2)
  • B
    78% (21)
  • C
    4% (1)
  • D
    11% (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.

ANMAP -PN -A -O -sS 192.168.2.0/24

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.

BNMAP -P0 -A -O -p1-65535 192.168.0/24Correct

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.

CNMAP -P0 -A -sT -p0-65535 192.168.0/16

The /16 CIDR notation targets a class B network spanning 65536 hosts rather than a single class C /24 subnet, making the scope incorrect.

DNMAP -PN -O -sS -p 1-1024 192.168.0/8

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

Topics

#NMAP#TCP scan#OS fingerprinting#service detection

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