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LFCS · Question #412

LFCS Question #412: Real Exam Question with Answer & Explanation

The correct answer is E: RST. Nmap provides various port scanning techniques, but "RST" is not a named scan type; rather, a Reset (RST) flag is part of the TCP connection termination process observed during scans.

Submitted by marco_it· Apr 18, 2026Networking

Question

Which of the following is NOT and valid scan technique with nmap?

Options

  • AWindow
  • BSYN
  • CACK
  • DConnect()
  • ERST

Explanation

Nmap provides various port scanning techniques, but "RST" is not a named scan type; rather, a Reset (RST) flag is part of the TCP connection termination process observed during scans.

Common mistakes.

  • A. The Nmap Window scan (-sW) is a valid technique that exploits the TCP Window field to determine port status.
  • B. The Nmap SYN scan (-sS), also known as "stealth scan," is a valid and common technique that sends SYN packets and watches for SYN/ACK or RST responses.
  • C. The Nmap ACK scan (-sA) is a valid technique used to map firewall rulesets and determine if ports are filtered or unfiltered.
  • D. The Nmap Connect() scan (-sT) is a valid technique that performs a full TCP three-way handshake, making it less stealthy but highly reliable.

Concept tested. Nmap scan techniques

Reference. https://nmap.org/book/man-briefoptions.html

Topics

#nmap#port scanning#network scanning#TCP/IP

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