Question 1hardmultiple choice
Full question →hardmultiple choiceObjective-mapped
A host can reach local devices but cannot reach the Internet. The host has a correct IP address and subnet mask, but no default gateway. What is the best explanation?
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 host can reach only local subnet destinations because it lacks a next hop for remote networks
This is correct because without a default gateway, the host has no normal path for off-subnet traffic.
B
Distractor review
The host automatically uses ARP to reach all Internet destinations directly
This is wrong because ARP is a local-link mechanism and does not resolve remote Internet hosts across routers.
C
Distractor review
The subnet mask alone should be enough to reach all networks
This is wrong because the mask identifies local scope but does not provide a path to remote networks.
D
Distractor review
The missing gateway forces the host into trunking mode
This is wrong because host gateway settings have nothing to do with switchport trunking.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A frequent exam trap is to think that the subnet mask alone enables a host to reach all networks. Candidates may incorrectly believe that ARP or other mechanisms can resolve remote IP addresses without a default gateway. This mistake overlooks the fact that ARP operates only on the local subnet and cannot resolve IP addresses beyond it. Without a default gateway, the host has no next-hop router to forward off-subnet traffic, so it cannot reach Internet destinations or other remote networks. Understanding this limitation is crucial to avoid selecting incorrect answers that confuse local address resolution with routing.
Technical deep dive
How to think about this question
A host on a network uses its IP address and subnet mask to determine which devices are local (on the same subnet) and which are remote (on different subnets). The subnet mask defines the network boundary, allowing the host to identify if a destination IP address is within its local subnet or outside it. For local destinations, the host sends frames directly using MAC addresses resolved by ARP. For remote destinations, the host must forward packets to a router, known as the default gateway, which routes traffic beyond the local subnet. The default gateway is a critical configuration on a host because it provides the next-hop IP address for all traffic destined outside the local subnet. Without a default gateway, the host cannot forward packets to remote networks, including the Internet. Even if the host has a correct IP address and subnet mask, it will only communicate within its local subnet. The host relies on the default gateway to route traffic to other subnets or external networks, making it essential for inter-network communication. A common exam trap is assuming that having a correct IP address and subnet mask alone allows full network connectivity. In reality, the absence of a default gateway restricts the host to local subnet communication only. Practically, this means the host can communicate with devices on the same subnet but cannot reach any device beyond it, including Internet hosts. This behavior is fundamental in Cisco networking and is frequently tested in CCNA exams to assess understanding of basic IP routing and host configuration.
KKey Concepts to Remember
- A host uses its subnet mask to determine whether a destination IP address is local or remote based on network boundaries.
- The default gateway is the next-hop router IP address that a host uses to send packets destined for remote networks.
- Without a default gateway, a host can communicate only with devices on the same local subnet and cannot reach external networks.
- ARP resolves MAC addresses only for devices within the local subnet and cannot resolve addresses beyond the local network.
- A correct IP address and subnet mask are necessary but not sufficient for Internet connectivity without a default gateway.
- The default gateway setting on a host enables routing of off-subnet traffic by directing packets to a router.
- Hosts rely on the default gateway to forward traffic to remote destinations, including the Internet, beyond the local subnet.
- Misunderstanding the role of the default gateway often leads to incorrect assumptions about host connectivity in exams.
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.
Related practice questions
Related 200-301 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
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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?
A host uses its subnet mask to determine whether a destination IP address is local or remote based on network boundaries.
What is the correct answer to this question?
The correct answer is: The host can reach only local subnet destinations because it lacks a next hop for remote networks — The best explanation is that the host can communicate only within its own local subnet because it lacks the next-hop information needed for off-subnet traffic. In plain language, the device knows who is local, but it does not know which router to use when the destination is elsewhere. This is one of the most important host-configuration concepts in CCNA. A valid IP address and mask are not enough by themselves when the destination lies on another network.
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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