Question 1hardmulti select
Full question →hardmulti selectObjective-mapped
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?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Best answer
The clients are missing a valid DNS server setting
Name resolution will fail if clients do not know where to send DNS queries.
B
Best answer
DNS queries may be blocked somewhere along the path
If UDP/TCP 53 traffic is filtered, hostnames fail while direct IP access can still work.
C
Distractor review
The routers are missing NTP configuration
Time sync is useful operationally but does not cause hostname-only failure.
D
Distractor review
The switch access ports should be changed to dynamic desirable
DTP settings do not explain name resolution failure.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A frequent exam trap is to assume that if users cannot browse websites by hostname, the problem must be with routing or the default gateway. However, the question states the default gateway is reachable and general internet connectivity works, which rules out routing issues. Another trap is to confuse unrelated configurations like NTP or switch port settings as causes for DNS failures. The key is to focus on DNS-specific causes: missing DNS server settings on clients or DNS traffic being blocked. Misinterpreting these symptoms leads to incorrect answers that do not address the root cause of hostname resolution failure.
Technical deep dive
How to think about this question
DNS (Domain Name System) is a critical IP service that maps human-friendly hostnames to IP addresses, allowing users to access resources by name rather than numeric IPs. In Cisco networks and the CCNA context, DNS resolution is essential for both end-user devices and network devices that rely on hostname resolution for management and connectivity. Without DNS, devices cannot translate domain names into IP addresses, causing failures in hostname-based browsing. When users can reach the default gateway and access the internet by IP address but not by hostname, the problem typically lies in DNS configuration or DNS traffic reachability. Clients must be configured with at least one valid DNS server IP address to send queries. Additionally, network devices, including routers and firewalls, must permit DNS traffic on UDP and TCP port 53. If DNS queries are blocked or filtered, the hostname resolution process fails even though IP routing remains functional. A common exam trap is to confuse general IP connectivity issues with DNS problems. The presence of successful ping to the default gateway and IP-based browsing confirms routing is working, so the problem is not with routing protocols or gateway configuration. Instead, the issue is DNS-specific, such as missing DNS server settings on clients or blocked DNS traffic. Practically, network administrators must verify DNS server IPs on clients and ensure no ACLs or firewall rules block DNS traffic to maintain hostname resolution.
KKey Concepts to Remember
- DNS servers translate human-readable hostnames into IP addresses, enabling hostname-based network communication.
- Clients must have a valid DNS server IP configured to resolve hostnames; missing this setting causes hostname resolution failure.
- Network devices and firewalls must allow DNS traffic (UDP and TCP port 53) to ensure DNS queries and responses are not blocked.
- If DNS queries are blocked, users can still access websites by IP address but cannot resolve hostnames to IPs.
- The default gateway being reachable confirms basic IP routing is functional but does not guarantee DNS functionality.
- DNS resolution failures are distinct from routing issues; routing problems affect all IP connectivity, not just hostname resolution.
- Cisco devices rely on proper DNS configuration for services like Cisco IOS name resolution and troubleshooting commands.
- Blocking DNS traffic or misconfiguring DNS settings are common causes of hostname-only connectivity issues in Cisco network environments.
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.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A router learns the same prefix from both OSPF and EIGRP. Which route is installed by default?
Question 2
A router shows this output: R1#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 10.1.1.2 1 FULL/DR 00:00:34 192.168.12.2 GigabitEthernet0/0 10.1.1.3 1 2WAY/DROTHER 00:00:39 192.168.12.3 GigabitEthernet0/0 Which statement is correct?
Question 3
What is the OSPF metric called?
Question 4
A non-root switch has two uplinks toward the root bridge. One path has a lower total STP cost than the other. What role will the lower-cost uplink have?
Question 5
A router interface applies this ACL inbound: 10 deny tcp any any eq 80 20 permit ip any any A user reports that web browsing to a server by IP address fails, but ping works. Which statement best explains the behavior?
Question 6
A router learns route 198.51.100.0/24 from OSPF with AD 110 and also has a static route to the same prefix configured with AD 150. Which route is installed?
FAQ
Questions learners often ask
What does this 200-301 question test?
DNS servers translate human-readable hostnames into IP addresses, enabling hostname-based network communication.
What is the correct answer to this question?
The correct answer is: The clients are missing a valid DNS server setting — If IP connectivity works but hostnames fail, the problem is usually DNS configuration or DNS reachability, not general routing.
What should I do if I get this 200-301 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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