- A
The DHCP server assigned the wrong IP to the server
Why wrong: The server's IP is 10.0.0.5 and is reachable; DHCP assignment is not the problem since the server is working.
- B
The DNS A record is incorrect
The A record points to 10.0.0.10 instead of 10.0.0.5, so DNS resolves to the wrong IP, preventing access by hostname.
- C
The router's port forwarding is misconfigured
Why wrong: Port forwarding is for external access; internal users don't use it, and the server is reachable by IP.
- D
The server's firewall is blocking DNS queries
Why wrong: DNS queries go to the DNS server, not the web server; the server's firewall wouldn't affect hostname resolution.
Question 57 of 1,020
Incorrect DNS A Record: Hostname Resolution Fails
This 220-1201 practice question tests your understanding of network 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.
A technician is troubleshooting a network where users can access the internet but cannot reach a specific internal web server by its hostname. The server's IP is 10.0.0.5, and pinging 10.0.0.5 works. The technician checks the DNS server and finds an A record for the server's name pointing to 10.0.0.10. What is the most likely issue?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"most likely"Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Quick Answer
The answer is an incorrect DNS A record, because the hostname resolves to the wrong IP address. When a user types the server’s hostname, the DNS lookup returns 10.0.0.10 instead of the actual server IP of 10.0.0.5, so traffic never reaches the intended resource. This is a classic DNS misconfiguration scenario on the CompTIA A+ Core 1 220-1201 exam, where you must distinguish between a connectivity problem and a name resolution problem—since pinging the correct IP works, the issue is clearly with the record, not the network or server itself. A common trap is assuming the server is down or that a firewall is blocking traffic, but the symptom of internet access working while a specific internal hostname fails points directly to a bad A record. Memory tip: “A record, A match”—the A record must match the actual server IP for hostname resolution to succeed.
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 DNS A record is incorrect
The correct answer is B because the DNS A record maps the server's hostname to 10.0.0.10, but the server's actual IP is 10.0.0.5. Since pinging the IP works, the network path to the server is functional; the failure to reach it by hostname is due to DNS resolving to the wrong address. This is a classic DNS misconfiguration where the A record does not match the server's assigned IP.
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.
- ✗
The DHCP server assigned the wrong IP to the server
Why it's wrong here
The server's IP is 10.0.0.5 and is reachable; DHCP assignment is not the problem since the server is working.
- ✓
The DNS A record is incorrect
Why this is correct
The A record points to 10.0.0.10 instead of 10.0.0.5, so DNS resolves to the wrong IP, preventing access by hostname.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
The router's port forwarding is misconfigured
Why it's wrong here
Port forwarding is for external access; internal users don't use it, and the server is reachable by IP.
- ✗
The server's firewall is blocking DNS queries
Common exam traps
Common exam trap: answer the scenario, not the keyword
CompTIA A+ often tests the distinction between connectivity issues (where pinging the IP fails) and name resolution issues (where pinging the IP works but hostname fails), and the trap here is that candidates may incorrectly suspect a firewall or DHCP problem instead of recognizing the DNS record mismatch.
Detailed technical explanation
How to think about this question
DNS A records are used to resolve hostnames to IPv4 addresses; when a client queries the DNS server for the server's hostname, it receives 10.0.0.10, causing traffic to be sent to a non-existent or incorrect host. The technician can verify this by running 'nslookup <hostname>' from a client to see the resolved IP, and then checking the DNS zone file or using 'dig' to confirm the A record mismatch. In real-world scenarios, this often occurs after server IP changes without updating the DNS record, leading to intermittent connectivity issues.
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 practitioner preparing for the 220-1201 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
Visual reference
Quick reference
Common DNS Record Types
| Record | Purpose | Example |
|---|---|---|
| A | IPv4 address mapping | example.com → 93.184.216.34 |
| AAAA | IPv6 address mapping | example.com → 2606:2800::1 |
| CNAME | Alias to another hostname | www → example.com |
| MX | Mail server for domain | example.com → mail.example.com (priority 10) |
| TXT | Text data (SPF, DKIM, verification) | v=spf1 include:_spf.example.com ~all |
| NS | Authoritative name servers | example.com NS ns1.example.com |
| PTR | Reverse DNS (IP → hostname) | 34.216.184.93.in-addr.arpa → example.com |
| SOA | Zone authority record | Primary NS, admin email, serial, TTL defaults |
What to study next
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FAQ
Questions learners often ask
What does this 220-1201 question test?
Network Services — This question tests Network Services — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The DNS A record is incorrect — The correct answer is B because the DNS A record maps the server's hostname to 10.0.0.10, but the server's actual IP is 10.0.0.5. Since pinging the IP works, the network path to the server is functional; the failure to reach it by hostname is due to DNS resolving to the wrong address. This is a classic DNS misconfiguration where the A record does not match the server's assigned IP.
What should I do if I get this 220-1201 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: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Last reviewed: Jul 4, 2026
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