The answer is a DNS problem, as name resolution is failing even though IP connectivity to the server works. Successful access by IP address confirms that Layer 3 routing and the network path are fully functional, so the issue must lie in the translation from hostname to IP. This classic DNS resolution failure when IP works scenario tests your ability to isolate symptoms: if the hostname fails but the IP succeeds, the root cause is almost always a missing, incorrect, or unreachable DNS server, a misconfigured host file, or a faulty DNS record. On the CCNA 200-301 v2 exam, this question appears in the network access and IP services domains, often as a trap to see if you jump to a connectivity or firewall issue instead of focusing on the naming service. A common memory tip is to think of the mnemonic “PING the IP, then PING the name”—if the IP works but the name does not, you know it’s not the wire, it’s the words.
CCNA Network Services and Security Practice Question
This 200-301 practice question tests your understanding of network services and security. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. A key principle to apply: dNS translates hostnames into IP addresses, enabling users to access network resources by name rather than numeric IPs.. 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.
Exhibit
User test results:
- ping 10.20.30.40 = success
- open http://10.20.30.40 = success
- open http://intranet.corp.local = fail
Users can reach an internal server by IP address but not by hostname. What is the most likely cause?
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.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Name resolution is failing even though IP connectivity to the server works.
The strongest explanation is a DNS problem rather than a raw IP connectivity problem. In practical terms, successful access by IP address shows that Layer 3 reachability to the server exists. Failure only when using the hostname strongly suggests name resolution is missing, incorrect, or unavailable.
This is a classic symptom-based troubleshooting question. The network path works, but the naming service does not.
Key principle: DNS translates hostnames into IP addresses, enabling users to access network resources by name rather than numeric IPs.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
Name resolution is failing even though IP connectivity to the server works.
Why this is correct
This is correct because the symptom points directly to a DNS-related problem.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
DNS translates hostnames into IP addresses, enabling users to access network resources by name rather than numeric IPs.
✗
The server must be in the wrong VLAN because IP works.
Why it's wrong here
This is wrong because successful IP access already shows the host can reach the server.
When this WOULD be correct
In a different scenario, if a question asked why a server is unreachable by IP address but reachable by hostname, and the context indicated that VLAN configurations were misapplied, then option B could be correct, suggesting the server is in a different VLAN than the clients.
✗
The default gateway is missing on the client.
Why it's wrong here
This is wrong because the client can already reach the server by IP.
When this WOULD be correct
In a different scenario, if a question stated that users cannot access any external resources or internal servers by IP address, and the context indicated that the client is on a different subnet without a configured default gateway, then this option would be correct.
✗
A GRE tunnel is required for hostname access.
Why it's wrong here
This is wrong because hostname access does not require GRE tunneling.
When this WOULD be correct
In a different question, if the scenario involved a network where hostname resolution required a GRE tunnel due to segmentation across different networks, then this option could be correct. For example, if the question stated that users could access servers in different VLANs only through GRE tunnels, this would validate the need for a GRE tunnel for hostname resolution.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.
✓Name resolution is failing even though IP connectivity to the server works.Correct answer▾
Why this is correct
This is correct because the symptom points directly to a DNS-related problem.
✗The server must be in the wrong VLAN because IP works.Wrong answer — click to see why▾
Why this is wrong here
This option is incorrect because being able to reach the server by IP address indicates that the server is correctly configured on the network and is not in the wrong VLAN. VLAN issues would typically prevent any connectivity, not just hostname resolution.
★ When this WOULD be the correct answer
In a different scenario, if a question asked why a server is unreachable by IP address but reachable by hostname, and the context indicated that VLAN configurations were misapplied, then option B could be correct, suggesting the server is in a different VLAN than the clients.
Why candidates choose this
Candidates might choose this option due to a misunderstanding of VLAN functionality, thinking that if hostname resolution fails, it could be related to VLAN misconfigurations, especially if they have encountered similar issues in practical scenarios.
✗The default gateway is missing on the client.Wrong answer — click to see why▾
Why this is wrong here
This option is incorrect because a missing default gateway would typically prevent any communication with external networks, including reaching the server by IP address. Since users can access the server via IP, the default gateway must be configured correctly.
★ When this WOULD be the correct answer
In a different scenario, if a question stated that users cannot access any external resources or internal servers by IP address, and the context indicated that the client is on a different subnet without a configured default gateway, then this option would be correct.
Why candidates choose this
Candidates may choose this option due to a misunderstanding of network fundamentals, believing that a default gateway is essential for any IP communication, leading them to overlook the specific context of the question.
✗A GRE tunnel is required for hostname access.Wrong answer — click to see why▾
Why this is wrong here
A GRE tunnel is not necessary for hostname access unless the hostname resolution specifically requires a tunnel for communication, which is not indicated in this scenario. The issue described relates to name resolution, not tunneling protocols.
★ When this WOULD be the correct answer
In a different question, if the scenario involved a network where hostname resolution required a GRE tunnel due to segmentation across different networks, then this option could be correct. For example, if the question stated that users could access servers in different VLANs only through GRE tunnels, this would validate the need for a GRE tunnel for hostname resolution.
Why candidates choose this
Candidates might choose this option because they associate GRE tunnels with complex network configurations and assume that hostname resolution issues could stem from tunneling requirements, especially in environments with multiple VLANs or subnets.
Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Common exam traps
Common exam trap: answer the scenario, not the keyword
A common exam trap is to confuse IP connectivity problems with DNS resolution issues. Candidates often select options related to VLAN misconfigurations or missing default gateways because they assume network path problems cause hostname failures. However, if users can reach the server by IP address, Layer 3 routing and VLAN membership are correct. The trap is ignoring the DNS layer, which is responsible for translating hostnames. Misinterpreting this leads to incorrect troubleshooting steps and wrong exam answers.
Trap categories for this question
Command / output trap
This is wrong because successful IP access already shows the host can reach the server.
Detailed technical explanation
How to think about this question
DNS (Domain Name System) is the core service that translates human-readable hostnames into IP addresses, enabling users to access resources by name rather than numeric IPs. In Cisco networking and CCNA contexts, DNS resolution is critical for network services and user convenience, especially when internal servers are accessed within an enterprise network. When users can reach a server by IP address but not by hostname, it indicates that the underlying Layer 3 routing and connectivity are intact, but the name resolution process is failing.
The decision process to diagnose this scenario begins by confirming IP connectivity, which is successful here. Since IP access works, the problem lies in DNS configuration or availability. This could be due to incorrect DNS server settings on the client, missing DNS records for the server hostname, or DNS server unavailability. Cisco devices rely on proper DNS settings to resolve names, and troubleshooting involves verifying DNS server IPs, ensuring the DNS service is operational, and confirming that the server’s hostname is correctly registered.
A common exam trap is to confuse IP connectivity issues with DNS problems. Candidates might incorrectly assume VLAN misconfigurations or missing gateways cause hostname resolution failures. However, since IP communication succeeds, these options are invalid. Practically, DNS failures manifest as inability to resolve names despite reachable IPs. Understanding this distinction helps avoid misdiagnosis and ensures focused troubleshooting on DNS rather than Layer 2 or Layer 3 connectivity issues.
KKey Concepts to Remember
DNS translates hostnames into IP addresses, enabling users to access network resources by name rather than numeric IPs.
Successful IP connectivity to a server confirms that Layer 3 routing and forwarding are functioning correctly.
Failure to reach a server by hostname despite IP access indicates a problem with DNS name resolution or DNS server configuration.
Cisco devices require correct DNS server IP addresses configured on clients to resolve hostnames properly.
DNS failures can result from missing DNS records, unreachable DNS servers, or incorrect DNS client settings.
IP connectivity issues such as VLAN misconfigurations or missing default gateways prevent access by both IP and hostname.
Troubleshooting hostname resolution problems should prioritize verifying DNS server availability and client DNS settings.
Exam questions testing hostname versus IP access often assess understanding of DNS role versus routing and VLAN configurations.
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
DNS translates hostnames into IP addresses, enabling users to access network resources by name rather than numeric IPs.
Real-world example
How this comes up in practice
A help-desk technician troubleshoots why a newly connected PC cannot reach shared printers on the same floor. The cable is good, the switch port is active, but the PC is in VLAN 20 and the printers are in VLAN 10. The uplink trunk only allows VLAN 10. A trunk being up does not mean every VLAN crosses it.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this 200-301 question in full detail.
Review dNS translates hostnames into IP addresses, enabling users to access network resources by name rather than numeric IPs., then practise related 200-301 questions on the same topic to reinforce the concept.
Network Services and Security — This question tests Network Services and Security — DNS translates hostnames into IP addresses, enabling users to access network resources by name rather than numeric IPs..
What is the correct answer to this question?
The correct answer is: Name resolution is failing even though IP connectivity to the server works. — The strongest explanation is a DNS problem rather than a raw IP connectivity problem. In practical terms, successful access by IP address shows that Layer 3 reachability to the server exists. Failure only when using the hostname strongly suggests name resolution is missing, incorrect, or unavailable.
This is a classic symptom-based troubleshooting question. The network path works, but the naming service does not.
What should I do if I get this 200-301 question wrong?
Review dNS translates hostnames into IP addresses, enabling users to access network resources by name rather than numeric IPs., then practise related 200-301 questions on the same topic to reinforce the concept.
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?
DNS translates hostnames into IP addresses, enabling users to access network resources by name rather than numeric IPs.
About these practice questions
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These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A user reports that websites can be opened by IP address but not by hostname. Which service is the strongest suspect?
medium
✓ A.DNS
B.STP
C.PAT
D.Port security
Why A: DNS is the strongest suspect because the network path clearly works at the IP layer. In practical terms, if the user can reach the site by numeric address, then routing and basic connectivity are functioning. The missing piece is name resolution, and that is exactly what DNS provides.
This is one of the clearest troubleshooting patterns in networking. If names fail but IP works, start with DNS.
Variation 2. A user can reach a remote web server by IP address but not by hostname. Which service should be checked first?
medium
✓ A.DNS
B.STP
C.PAT
D.Port security
Why A: DNS should be checked first. In plain language, the path to the server appears to work because the user can reach it by numeric address. The missing function is the translation from hostname to IP-related information, and that is exactly what DNS provides.
This is one of the clearest service-troubleshooting patterns in networking. If IP works but the name fails, DNS becomes the strongest first suspect. The correct answer is therefore the name-resolution service rather than a routing or switching feature.
Variation 3. Users can reach a server by IP address but not by hostname. Which service should be checked first?
easy
A.NTP
✓ B.DNS
C.QoS
D.HSRP
Why B: If the server is reachable by IP but not by name, the likely issue is name resolution, which points to DNS.
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