LPIC-2 Exam 202 (Linux Engineer) — Question 7

It has been discovered that the company mail server is configured as an open relay. Which of the following actions would help prevent the mail server from being used as an open relay while maintaining the possibility to receive company mails? (Choose two.)

Answer options

• A. Restrict Postfix to only accept e-mail for domains hosted on this server
• B. Configure Dovecot to support IMAP connectivity
• C. Configure netfilter to not permit port 25 traffic on the public network
• D. Restrict Postfix to only relay outbound SMTP from the internal network
• E. Upgrade the mailbox format from mbox to maildir

Correct answer: C, D

Explanation

Options C and D are correct because restricting port 25 traffic on the public network helps prevent unauthorized relay, while limiting Postfix to relay only from the internal network ensures legitimate use while blocking external abuse. Options A, B, and E do not directly address the open relay issue, as they focus on other configurations that do not prevent unauthorized mail relay.