What is an 'open relay' in the context of MTA security?

An MTA that uses TLS for all connections

An MTA that logs all messages to a public directory

An MTA that only accepts mail from authenticated users

An MTA that allows anyone to relay mail through it

A company runs a Postfix mail server on a public IP. They want to allow their own users (authenticated via SASL) to send mail through the server, but they must prevent unauthorized external hosts from using it to relay spam. Which Postfix configuration directive is essential to enforce this?

smtpd_relay_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination

smtpd_recipient_restrictions = permit_mynetworks, reject_unauth_destination

Which of the following is a common method to prevent unauthorized relaying on an MTA?

Setting the MTA to accept mail from any domain

Using a high port number for SMTP

Restricting relaying to specific networks or requiring SMTP authentication

A user 'carol' has a .forward file containing 'carol@example.org'. Mail sent to carol@example.com is being bounced with 'local loop detected'. The administrator needs to fix this while still forwarding carol's mail to her external address. What is the correct approach?

Change the .forward to '\carol, carol@example.org'

Set 'carol@example.org' as the only entry in .forward

Remove the .forward file and create an alias 'carol: carol@example.org'

Add 'carol@example.org' to mydestination

LPI LPIC-1:Linux Administrator (101-500)

Domain 8Objective 3

108.3 Mail Transfer Agent (MTA) Basics LPIC-1 Practice Questions (Page 5)

Part of the Topic 108: Essential System Services domain, which makes up ~9% of our current practice bank. Linux Professional Institute does not publish an official question count, but from its 90-minute exam (~35–60 total, ~3–5 in this domain), expect 1–1 from this objective — we provide 29 practice questions to prepare you well beyond it. (estimate)

29questions here

6free pages

9concepts

Questions 21–25

21foundation · easy
A message is stuck in the mail queue. Which command would you use to force an immediate delivery attempt?
Select an answer first
22foundation · easy
What is an 'open relay' in the context of MTA security?
Select an answer first
23application · medium
A company runs a Postfix mail server on a public IP. They want to allow their own users (authenticated via SASL) to send mail through the server, but they must prevent unauthorized external hosts from using it to relay spam. Which Postfix configuration directive is essential to enforce this?
Select an answer first
24foundation · easy
Which of the following is a common method to prevent unauthorized relaying on an MTA?
Select an answer first
25expert · medium
A user 'carol' has a .forward file containing 'carol@example.org'. Mail sent to carol@example.com is being bounced with 'local loop detected'. The administrator needs to fix this while still forwarding carol's mail to her external address. What is the correct approach?
Select an answer first

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