Certified Ethical Hacker (CEH v11) — Question 308

Andrew is an Ethical Hacker who was assigned the task of discovering all the active devices hidden by a restrictive firewall in the IPv4 range in a given target network.
Which of the following host discovery techniques must he use to perform the given task?

Answer options

• A. UDP scan
• B. ARP ping scan
• C. ACK flag probe scan
• D. TCP Maimon scan

Correct answer: B

Explanation

The correct answer is B, ARP ping scan, as it is effective in discovering devices on the local network segment by sending ARP requests, which are not typically blocked by firewalls. The other options, such as UDP scan and TCP Maimon scan, may not yield results due to firewall restrictions, and ACK flag probe scans are generally used for mapping out firewall rules rather than discovering hosts.