- A
zone "example.com" { type master; file "db.example.com"; update-policy { grant 192.168.1.0/24 zonesub ANY; }; };
Why wrong: update-policy is used for fine-grained access control typically with TSIG keys, not for IP-based grants.
- B
zone "example.com" { type master; file "db.example.com"; allow-transfer { 192.168.1.0/24; }; };
Why wrong: allow-transfer controls zone transfers, not dynamic updates.
- C
zone "example.com" { type master; file "db.example.com"; allow-update { 192.168.1.0/24; }; };
allow-update permits dynamic updates from the subnet. The zone file is updated immediately on each update.
- D
zone "example.com" { type master; file "db.example.com"; also-notify { 192.168.1.0/24; }; };
Why wrong: also-notify specifies additional servers to notify, unrelated to dynamic updates.
Quick Answer
The correct configuration is `allow-update { 192.168.1.0/24; };` within the zone definition, because this BIND statement explicitly permits dynamic DNS updates from the specified subnet as defined by RFC 2136. When a zone is configured as type master, any accepted dynamic update is written to the zone file immediately by default, ensuring real-time synchronization without requiring a manual reload. On the LPIC-2 exam, this topic tests your understanding of secure DNS management under Objective 208.2, where a common trap is confusing `allow-update` with `allow-transfer` or forgetting that the zone must be a master for immediate file writes. A helpful memory tip is to think of "allow-update" as the gatekeeper for dynamic changes—only the subnet you explicitly list can push updates through, and the master zone writes them down instantly.
LPIC-2 DNS, Web and Mail Services Practice Question
This LPIC-2 practice question tests your understanding of dns, web and mail services. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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.
An administrator needs to configure a BIND DNS server to allow dynamic updates from a specific subnet (192.168.1.0/24) for the zone 'example.com'. The administrator must also ensure that the zone file is updated immediately after a dynamic update. Which configuration accomplishes this?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"immediately / without restart"Why it matters: Time or reboot constraint — the correct answer must take effect right away without requiring a reboot or reload.
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
zone "example.com" { type master; file "db.example.com"; allow-update { 192.168.1.0/24; }; };
Option C is correct because the `allow-update` statement in BIND explicitly permits dynamic DNS updates (RFC 2136) from specified sources, such as the subnet 192.168.1.0/24. Dynamic updates are written to the zone file immediately by default when using a master zone, ensuring the file is updated in real time.
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.
- ✗
zone "example.com" { type master; file "db.example.com"; update-policy { grant 192.168.1.0/24 zonesub ANY; }; };
Why it's wrong here
update-policy is used for fine-grained access control typically with TSIG keys, not for IP-based grants.
- ✗
zone "example.com" { type master; file "db.example.com"; allow-transfer { 192.168.1.0/24; }; };
Why it's wrong here
allow-transfer controls zone transfers, not dynamic updates.
- ✓
zone "example.com" { type master; file "db.example.com"; allow-update { 192.168.1.0/24; }; };
Why this is correct
allow-update permits dynamic updates from the subnet. The zone file is updated immediately on each update.
Clue confirmation
The clue word "immediately / without restart" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
zone "example.com" { type master; file "db.example.com"; also-notify { 192.168.1.0/24; }; };
Why it's wrong here
also-notify specifies additional servers to notify, unrelated to dynamic updates.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates confuse `allow-update` with `allow-transfer` or `also-notify`, mistakenly thinking those directives enable dynamic updates, or they misapply `update-policy` syntax by using a subnet instead of a key-based identity.
Detailed technical explanation
How to think about this question
Dynamic updates in BIND use the `allow-update` or `update-policy` directives; `allow-update` accepts IP addresses or ACLs, while `update-policy` offers finer granularity with TSIG keys. The zone file is updated immediately because BIND writes changes to the file on each update by default (unless `journal` is used for incremental journaling). In real-world scenarios, `allow-update` is often used for DHCP-DNS integration, but it can pose security risks if not restricted to trusted subnets.
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.
- →
DNS, Web and Mail Services — study guide chapter
Learn the concepts, then practise the questions
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DNS, Web and Mail Services practice questions
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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: zone "example.com" { type master; file "db.example.com"; allow-update { 192.168.1.0/24; }; }; — Option C is correct because the `allow-update` statement in BIND explicitly permits dynamic DNS updates (RFC 2136) from specified sources, such as the subnet 192.168.1.0/24. Dynamic updates are written to the zone file immediately by default when using a master zone, ensuring the file is updated in real time.
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: "immediately / without restart". Time or reboot constraint — the correct answer must take effect right away without requiring a reboot or reload.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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Last reviewed: Jun 11, 2026
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.
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