DNS, Web and Mail Services →easyMultiple ChoiceObjective-mapped

LPIC-2 DNS, Web and Mail Services Practice Question

Exhibit

; <<>> DiG 9.16.1 <<>> -x 192.0.2.1
;; QUESTION SECTION:
;1.2.0.192.in-addr.arpa.       IN      PTR

;; AUTHORITY SECTION:
2.0.192.in-addr.arpa.  3600    IN      SOA     ns1.example.com. admin.example.com. 2023100101 3600 900 604800 86400

;; Query time: 1 msec
;; SERVER: 192.0.2.1#53(192.0.2.1)
;; WHEN: Sat Oct 01 12:00:00 2023
;; MSG SIZE  rcvd: 80

Refer to the exhibit. What is wrong with the reverse DNS resolution for 192.0.2.1?

⚠ Common exam trap

Many exam-takers confuse NXDOMAIN (missing record) with SERVFAIL (server error) or assume delegation issues, but the authoritative flag confirms the server is responsible, so the only logical cause is a missing PTR record.

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

✓

The PTR record for 192.0.2.1 is missing.

The reverse DNS resolution for 192.0.2.1 requires a PTR record in the reverse zone file. The query returns NXDOMAIN, which indicates that the PTR record for 1.2.0.192.in-addr.arpa does not exist, meaning the record is missing. Without this PTR record, the reverse lookup fails.

Answer analysis

Option-by-option breakdown

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

✗
The reverse zone is not delegated.
Why it's wrong here
Delegation is not indicated; the server is authoritative.
✗
The query should be for 1.2.0.192.in-addr.arpa.
Why it's wrong here
The query syntax is correct; -x automatically constructs the correct format.
✗
The server is not authoritative for the reverse zone.
Why it's wrong here
The authority section shows SOA for 2.0.192.in-addr.arpa, indicating it is authoritative.
✓
The PTR record for 192.0.2.1 is missing.
Why this is correct
No answer section means no PTR record exists for that IP.

Visual reference

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LPIC-2 DNS, Web and Mail Services Practice Question

Exhibit

Why each option matters

Option-by-option breakdown

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