Certified Ethical Hacker (CEH) — Question 38

While examining audit logs, you discover that people are able to telnet into the SMTP server on port 25. You would like to block this, though you do not see any evidence of an attack or other wrong doing. However, you are concerned about affecting the normal functionality of the email server. From the following options choose how best you can achieve this objective?

Answer options

• A. Block port 25 at the firewall.
• B. Shut off the SMTP service on the server.
• C. Force all connections to use a username and password.
• D. Switch from Windows Exchange to UNIX Sendmail.
• E. None of the above.

Correct answer: E

Explanation

The correct answer is E because blocking port 25 or shutting down the SMTP service would disrupt email functionality, and enforcing a username and password does not directly prevent telnet access. Switching to UNIX Sendmail is unnecessary and does not address the issue of restricting telnet access effectively.