Question 310 of 511
DNS, Web and Mail ServicesmediumMultiple ChoiceObjective-mapped

Quick Answer

The answer is to run `rndc notify company.com` on the master to force zone transfer to slave servers. This command re-sends NOTIFY messages to all configured slaves, which is necessary because the slaves’ logs show a transfer started but never completed, indicating they missed or ignored the initial notification despite the master having no errors. On the LPIC-2 exam, this scenario tests your understanding of BIND’s NOTIFY mechanism and zone transfer troubleshooting—a common trap is assuming a failed transfer is always a firewall or serial number issue, when in fact a manual `rndc notify` can resolve transient notification failures. Remember that `rndc reload` increments the serial and loads the zone but does not guarantee slaves receive the NOTIFY; `rndc notify` explicitly triggers the notification process. A useful memory tip: “Reload loads, notify nags”—the master loads the zone, but you must nudge the slaves with a forced notify to complete the transfer.

LPIC-2 DNS, Web and Mail Services Practice Question

This LPIC-2 practice question tests your understanding of dns, web and mail services. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.

You are the administrator of a medium-sized company that runs its own authoritative DNS servers for the domain 'company.com'. The primary DNS server is a BIND9 master, and there are two slaves. Recently, you updated the zone file on the master to add a new subdomain 'lab.company.com' with an A record pointing to 10.0.0.10. After the update, you increased the serial number and ran 'rndc reload'. However, after several hours, some external clients report that they cannot resolve 'lab.company.com'. You check the master server and find that the zone file contains the new record. You also check the slave servers and find that they still have the old zone data. The serial number on the master is 2025011501, while the slaves show 2025011400. The master's syslog shows no errors. The slaves' syslogs show 'zone company.com/IN: Transfer started.' but no completion messages. Firewall rules allow TCP and UDP port 53 between all DNS servers. What should you do to resolve the issue?

Clue words in this question

Noticing these words before you look at the options changes how you read each choice.

  • Clue: "primary"

    Why it matters: Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.

Question 1mediummultiple choice
Read the full DNS explanation →

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

Run 'rndc notify company.com' on the master to force sending NOTIFY messages to the slaves.

Option D is correct because the master's syslog shows no errors and the slaves' logs indicate a transfer started but never completed, which suggests the NOTIFY messages were sent but the slaves may have missed or ignored them due to a transient issue. Running 'rndc notify company.com' forces the master to re-send NOTIFY messages to all configured slaves, prompting them to initiate a zone transfer immediately, which should update the stale zone data on the slaves.

Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Answer analysis

Option-by-option breakdown

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

  • Check the 'allow-transfer' ACL on the master; it might be restricting transfers to the slaves.

    Why it's wrong here

    The logs show 'Transfer started', so the master allowed the connection; the problem is the transfer not completing, possibly due to data transfer issues.

  • Increase the serial number again on the master to a higher value and wait for the slaves to refresh.

    Why it's wrong here

    The slaves are not contacting the master, likely because they haven't received a NOTIFY. Increasing serial number alone won't trigger a transfer without a NOTIFY or refresh interval.

  • Restart the BIND service on the slave servers.

    Why it's wrong here

    Restarting slaves might cause them to check the serial number at startup, but it is not guaranteed and may cause brief downtime.

  • Run 'rndc notify company.com' on the master to force sending NOTIFY messages to the slaves.

    Why this is correct

    This will cause the master to send NOTIFY messages to all configured slaves, prompting them to start a zone transfer.

    Clue confirmation

    The clue word "primary" in the question point toward this answer.

    Related concept

    Read the scenario before looking for a memorised answer.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates assume the serial number mismatch alone will eventually trigger a transfer via the slave's refresh timer, but the question emphasizes that hours have passed and the transfer started but never completed, indicating a stalled TCP connection that requires a forced NOTIFY to re-initiate the transfer.

Trap categories for this question

  • Command / output trap

    The logs show 'Transfer started', so the master allowed the connection; the problem is the transfer not completing, possibly due to data transfer issues.

Detailed technical explanation

How to think about this question

BIND uses NOTIFY messages (RFC 1996) to inform slaves of zone changes; when a slave receives a NOTIFY with a higher serial number, it should initiate an AXFR or IXFR query. However, if the slave's TCP connection for the transfer is blocked or times out (e.g., due to a firewall state issue or network congestion), the transfer may start but never complete, leaving the zone stale. The 'rndc notify' command re-sends NOTIFY messages, which can trigger a fresh transfer attempt even if the previous one stalled.

KKey Concepts to Remember

  • Read the scenario before looking for a memorised answer.
  • Find the constraint that changes the correct option.
  • Eliminate answers that are true in general but not in this case.

TExam Day Tips

  • Watch for words such as best, first, most likely and least administrative effort.
  • Review why wrong options are wrong, not only why the correct option is correct.

Key takeaway

Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Real-world example

How this comes up in practice

A security administrator must allow nursing staff to reach a patient records server while blocking access from the guest Wi-Fi VLAN. After applying an extended ACL, traffic is still blocked from nursing workstations. The ACL was applied outbound instead of inbound on the wrong interface. Questions like this test ACL direction and placement rules.

What to study next

Got this wrong? Here's your next step.

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

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FAQ

Questions learners often ask

What does this LPIC-2 question test?

DNS, Web and Mail Services — This question tests DNS, Web and Mail Services — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: Run 'rndc notify company.com' on the master to force sending NOTIFY messages to the slaves. — Option D is correct because the master's syslog shows no errors and the slaves' logs indicate a transfer started but never completed, which suggests the NOTIFY messages were sent but the slaves may have missed or ignored them due to a transient issue. Running 'rndc notify company.com' forces the master to re-send NOTIFY messages to all configured slaves, prompting them to initiate a zone transfer immediately, which should update the stale zone data on the slaves.

What should I do if I get this LPIC-2 question wrong?

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

Are there clue words in this question I should notice?

Yes — watch for: "primary". Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

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Last reviewed: Jun 11, 2026

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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.