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DNS, Web and Mail ServicesmediumMultiple ChoiceObjective-mapped

LPIC-2 DNS, Web and Mail Services Practice Question

Exhibit

$ORIGIN example.com.
@       IN      SOA     ns1.example.com. admin.example.com. (
                        2023100101      ; serial
                        3600            ; refresh
                        900             ; retry
                        604800          ; expire
                        86400 )         ; minimum
        IN      NS      ns1
        IN      MX      10 mail
ns1     IN      A       192.0.2.1
mail    IN      A       192.0.2.10
www     IN      A       192.0.2.20

Refer to the exhibit. A DNS query for 'ftp.example.com' returns NXDOMAIN. What configuration change would best resolve this?

⚠ Common exam trap

Many candidates confuse NXDOMAIN with a server configuration issue (like recursion) or think that a CNAME can substitute for a missing A record, but NXDOMAIN specifically means the name is absent from the zone, requiring a direct resource record addition.

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

Add an A record for ftp pointing to an IP address.

An NXDOMAIN response means the queried domain name does not exist in the zone. To resolve 'ftp.example.com', a DNS record must be created that maps the name to an IP address. Option D adds an A record, which directly provides the IPv4 address for the host, making the query succeed.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • Add a CNAME record for ftp pointing to www.example.com.

    Why it's wrong here

    Adding a CNAME for 'ftp' pointing to 'www.example.com' fails because it only creates an alias, and the problem implies 'ftp.example.com' needs its own distinct IP address to resolve the NXDOMAIN, likely for an FTP server. This option is tempting because CNAME records are used to map one hostname to another. It would be the correct choice if 'ftp.example.com' was intended to be an alias for 'www.example.com', resolving to the same IP address as the web server.

  • Increase the serial number in the SOA record.

    Why it's wrong here

    Increasing serial notifies secondaries but does not create missing records.

  • Ensure recursion is enabled on the server.

    Why it's wrong here

    Recursion is not needed; the server is authoritative for the zone.

  • Add an A record for ftp pointing to an IP address.

    Why this is correct

    Adding an A record directly answers the query for ftp.example.com.

Visual reference

Client Recursive Resolver Root DNS (13 root servers) TLD DNS (.com, .org, …) Authoritative example.com query IP addr answer

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JA

Written by Johnson Ajibi, MSc IT Security

Senior Network & Security Engineer · founder of Courseiva

This LPIC-2 practice question is part of Courseiva's free LPI certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the LPIC-2 exam.