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GCIH · Question #19

You want to scan your network quickly to detect live hosts by using ICMP ECHO Requests. What type of scanning will you perform to accomplish the task?

The correct answer is D. Ping sweep scan. A ping sweep sends ICMP ECHO Request packets to multiple hosts and identifies live hosts based on which ones send back an ICMP ECHO Reply. This is the fastest method for basic host discovery across a subnet.

Reconnaissance, Scanning, and Enumeration

Question

You want to scan your network quickly to detect live hosts by using ICMP ECHO Requests. What type of scanning will you perform to accomplish the task?

Options

  • AIdle scan
  • BTCP SYN scan
  • CXMAS scan
  • DPing sweep scan

How the community answered

(43 responses)
  • A
    2% (1)
  • B
    2% (1)
  • C
    7% (3)
  • D
    88% (38)

Why each option

A ping sweep sends ICMP ECHO Request packets to multiple hosts and identifies live hosts based on which ones send back an ICMP ECHO Reply. This is the fastest method for basic host discovery across a subnet.

AIdle scan

An idle scan exploits a zombie host's IP ID sequence to stealthily probe ports on a target and does not use ICMP ECHO for host discovery.

BTCP SYN scan

A TCP SYN scan sends TCP SYN packets to probe for open ports on a known host, not to discover live hosts via ICMP.

CXMAS scan

An XMAS scan sends TCP packets with FIN, PSH, and URG flags set to infer port states, and has no relation to ICMP-based host discovery.

DPing sweep scanCorrect

A ping sweep - also called ICMP sweep - sends ICMP ECHO Request (Type 8) packets to a range of IP addresses and marks hosts that respond with an ICMP ECHO Reply (Type 0) as alive. It is specifically designed for rapid, large-scale host discovery rather than port enumeration. Tools like nmap implement this with the -sn -PE flags for exactly this purpose.

Concept tested: ICMP-based host discovery using ping sweep

Source: https://nmap.org/book/man-host-discovery.html

Topics

#ping sweep#ICMP echo#host discovery#network scanning

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