Certified Ethical Hacker (CEH) — Question 63

A company has publicly hosted web applications and an internal Intranet protected by a firewall. Which technique will help protect against enumeration?

Answer options

• A. Reject all invalid email received via SMTP.
• B. Allow full DNS zone transfers.
• C. Remove A records for internal hosts.
• D. Enable null session pipes.

Correct answer: C

Explanation

The correct answer, C, is effective because removing A records for internal hosts prevents external entities from discovering internal IP addresses, thereby mitigating the risk of enumeration. Option A addresses email security but does not relate to host enumeration. Option B would actually expose DNS information and increase vulnerability. Option D can lead to security risks by allowing unauthenticated access to resources.