The answer is a DNS failure or DNS configuration problem, because successful browsing by IP address proves that IP connectivity and the network path to the destination are fully functional. When the same service fails only by hostname, the issue is isolated to name resolution, meaning the client cannot translate the domain name into an IP address, even though routing, switching, and raw connectivity are working. On the CCNA 200-301 v2 exam, this scenario tests your ability to differentiate between Layer 3 connectivity problems and application-layer naming issues, often appearing in troubleshooting questions where a single exhibit shows a ping to an IP succeeding but a ping to a hostname failing. A common trap is to blame routing or ACLs, but the key insight is that if IP works, the path is fine—only the DNS lookup is broken. Memory tip: “IP works, name fails? DNS nails it.”
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 (Domain Name System) resolves hostnames to IP addresses, enabling clients to access network resources using human-readable names.. 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
Client tests:
- ping 172.16.20.50 = success
- open http://172.16.20.50 = success
- open http://portal.corp.example = fail
Based on the exhibit, what is the strongest explanation for why clients can browse by IP address but not by hostname?
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 works.
The strongest explanation is a DNS failure or DNS configuration problem. In practical terms, successful browsing by IP address shows that the client can already reach the destination over the network path. When the same service fails only by hostname, the issue is much more likely in name resolution than in routing, switching, or raw connectivity.
This is one of the most useful support patterns because it quickly separates path problems from naming problems.
Key principle: DNS (Domain Name System) resolves hostnames to IP addresses, enabling clients to access network resources using human-readable names.
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 works.
Why this is correct
This is correct because the difference between IP success and hostname failure points to DNS.
Related concept
DNS (Domain Name System) resolves hostnames to IP addresses, enabling clients to access network resources using human-readable names.
✗
The client has the wrong default gateway.
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 where a client is unable to connect to any external resources, including both IP and hostname, the question might ask why the client cannot access the internet. In that case, if the default gateway is misconfigured, it would be the correct answer as it would block all traffic.
✗
The switch trunk native VLAN is wrong.
Why it's wrong here
This is wrong because the symptom is specifically name-based failure, not a total path failure.
When this WOULD be correct
In a different scenario, if the question involved a network where clients are unable to communicate across VLANs due to misconfigured trunk settings, and the context indicated that hostname resolution relies on inter-VLAN routing, then this option could be correct.
✗
The server must run PPP before hostnames can work.
Why it's wrong here
This is wrong because PPP is unrelated to DNS-based service access here.
When this WOULD be correct
In a scenario where the question asks about the necessity of specific protocols for establishing network connections, such as a question about how to configure a network for dial-up connections, this option could be correct if it stated that PPP is required for establishing a connection before DNS queries can be made.
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 works.Correct answer▾
Why this is correct
This is correct because the difference between IP success and hostname failure points to DNS.
✗The client has the wrong default gateway.Wrong answer — click to see why▾
Why this is wrong here
This option is incorrect because having the wrong default gateway would typically prevent any connectivity, including both IP and hostname resolution. Since clients can browse by IP address, it indicates that the default gateway is correctly configured for IP traffic.
★ When this WOULD be the correct answer
In a different scenario where a client is unable to connect to any external resources, including both IP and hostname, the question might ask why the client cannot access the internet. In that case, if the default gateway is misconfigured, it would be the correct answer as it would block all traffic.
Why candidates choose this
Candidates may choose this option because they associate default gateway issues with connectivity problems, leading them to mistakenly believe it could affect hostname resolution despite existing IP connectivity.
✗The switch trunk native VLAN is wrong.Wrong answer — click to see why▾
Why this is wrong here
This option is wrong because the issue of clients being unable to browse by hostname is related to name resolution, not the configuration of the switch trunk native VLAN. The native VLAN configuration affects VLAN tagging and traffic flow, not DNS resolution.
★ When this WOULD be the correct answer
In a different scenario, if the question involved a network where clients are unable to communicate across VLANs due to misconfigured trunk settings, and the context indicated that hostname resolution relies on inter-VLAN routing, then this option could be correct.
Why candidates choose this
Candidates might choose this option due to a misunderstanding of how VLANs and trunking affect network communication, mistakenly believing that improper VLAN configurations could impact hostname resolution.
✗The server must run PPP before hostnames can work.Wrong answer — click to see why▾
Why this is wrong here
This option is incorrect because PPP (Point-to-Point Protocol) is not required for hostname resolution; it primarily deals with data link layer communication. Hostname resolution typically relies on DNS or local name resolution methods, not PPP.
★ When this WOULD be the correct answer
In a scenario where the question asks about the necessity of specific protocols for establishing network connections, such as a question about how to configure a network for dial-up connections, this option could be correct if it stated that PPP is required for establishing a connection before DNS queries can be made.
Why candidates choose this
Candidates might find this option tempting due to a misunderstanding of the relationship between network protocols and name resolution, leading them to incorrectly associate PPP with hostname functionality.
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 frequent exam trap is assuming that if hostname resolution fails, the problem must be with routing or VLAN configurations such as the default gateway or switch trunknative VLAN. However, since clients can browse by IP address, these path elements are functioning correctly. Misattributing the failure to routing or VLAN issues wastes time and leads to incorrect answers. The key mistake is not recognizing that DNS operates at a higher layer and that name resolution failures are distinct from IP connectivity problems.
Detailed technical explanation
How to think about this question
DNS is a critical IP service that maps human-friendly hostnames to IP addresses, allowing users to access resources without memorizing numeric addresses. When a client attempts to browse a server by hostname, it sends a DNS query to a configured DNS server. If the DNS server responds correctly, the client receives the IP address and initiates communication. This process is fundamental in Cisco networking environments and is covered in the CCNA 200-301 exam under IP Services.
When clients can browse by IP address but not by hostname, the network path is confirmed operational, indicating that routing, switching, and default gateway configurations are correct. The failure lies in the DNS resolution step. This means either the DNS server is unreachable, misconfigured, or the client has incorrect DNS settings. Cisco devices often use DHCP to provide DNS server information, so misconfigurations in DHCP or static DNS entries can cause this issue.
A common exam trap is to confuse connectivity issues with DNS problems. For example, assuming the default gateway or VLAN trunking is at fault when IP connectivity works leads to incorrect conclusions. Practically, network engineers verify IP connectivity first, then isolate DNS issues by checking DNS server reachability and client DNS configurations. Understanding this separation is vital for troubleshooting and passing the CCNA exam.
KKey Concepts to Remember
DNS (Domain Name System) resolves hostnames to IP addresses, enabling clients to access network resources using human-readable names.
Successful IP connectivity with failed hostname access indicates a problem specifically in the DNS name resolution process, not in routing or switching.
Clients rely on configured DNS servers to translate hostnames; if DNS is misconfigured or unreachable, hostname-based access fails.
A correct default gateway allows IP packets to route properly, but it does not affect DNS resolution directly.
Switch trunk native VLAN mismatches cause VLAN tagging issues affecting connectivity, but they do not selectively block hostname resolution.
PPP (Point-to-Point Protocol) is unrelated to DNS or hostname resolution in typical LAN browsing scenarios.
Troubleshooting hostname resolution issues requires verifying DNS server settings, DNS service availability, and client DNS configuration.
Network path verification by IP address helps isolate whether connectivity or name resolution is the root cause of access problems.
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 (Domain Name System) resolves hostnames to IP addresses, enabling clients to access network resources using human-readable names.
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 (Domain Name System) resolves hostnames to IP addresses, enabling clients to access network resources using human-readable names., 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 (Domain Name System) resolves hostnames to IP addresses, enabling clients to access network resources using human-readable names..
What is the correct answer to this question?
The correct answer is: Name resolution is failing even though IP connectivity works. — The strongest explanation is a DNS failure or DNS configuration problem. In practical terms, successful browsing by IP address shows that the client can already reach the destination over the network path. When the same service fails only by hostname, the issue is much more likely in name resolution than in routing, switching, or raw connectivity.
This is one of the most useful support patterns because it quickly separates path problems from naming problems.
What should I do if I get this 200-301 question wrong?
Review dNS (Domain Name System) resolves hostnames to IP addresses, enabling clients to access network resources using human-readable names., then practise related 200-301 questions on the same topic to reinforce the concept.
What is the key concept behind this question?
DNS (Domain Name System) resolves hostnames to IP addresses, enabling clients to access network resources using human-readable names.
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. Clients on a network can browse the internet by IP address but fail when using hostnames. What is the most likely problem?
hard
A.The default gateway on the PC is incorrect.
✓ B.The client is using the wrong DNS server address.
C.NAT overload is failing on the edge router.
D.The switchport must be converted to a routed port.
Why B: The client can browse by IP address but not by hostname, which indicates that IP connectivity and routing are functional, but name resolution is failing. Since DNS translates hostnames to IP addresses, the most likely fault is that the client is configured with an incorrect DNS server address, preventing it from resolving domain names.
Variation 2. Users can browse websites by IP address but not by hostname. The default gateway is reachable and general internet connectivity works. Which two causes are the most likely?
hard
✓ A.The clients are missing a valid DNS server setting
✓ B.DNS queries may be blocked somewhere along the path
C.The routers are missing NTP configuration
D.The switch access ports should be changed to dynamic desirable
Why A: If IP connectivity works but hostnames fail, the problem is usually DNS configuration or DNS reachability, not general routing.
Variation 3. A host receives its IP address automatically but cannot resolve hostnames. Which additional service information is most likely missing from its configuration?
medium
✓ A.A DNS server address
B.A new MAC address
C.A trunk native VLAN
D.An OSPF router ID
Why A: If the host receives an IP address but cannot resolve hostnames, the most likely missing information is a DNS server setting. In plain language, the device has enough configuration to join the network but not enough to ask where hostnames map in IP terms. DHCP can provide this DNS server information automatically, and if it is missing, the host may still communicate by IP while failing on names.
This is a common service-troubleshooting pattern because it separates address configuration from name resolution. The correct answer is the missing DNS-related setting rather than the IP address itself or the subnet mask.
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