Certified Ethical Hacker (CEH v10) — Question 176

Which of the following is considered as one of the most reliable forms of TCP scanning?

Answer options

• A. TCP Connect/Full Open Scan
• B. Half-open Scan
• C. NULL Scan
• D. Xmas Scan

Correct answer: A

Explanation

The TCP Connect/Full Open Scan is considered the most reliable because it completes the TCP handshake, ensuring that the port status is accurately determined. In contrast, the Half-open Scan does not complete the connection, and the NULL and Xmas scans may be less reliable as they rely on specific responses that can be blocked by firewalls or IDS systems.