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. 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.
Exhibit
Client IP address: 192.168.50.23/24
Ping to 192.168.50.1 succeeds
Ping to 8.8.8.8 fails
DHCP pool intended for VLAN 50 users
A client receives an IP address but cannot reach remote networks. Which DHCP option is most likely missing or incorrect?
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
✓
Default gateway option
The client can obtain an IP address but cannot reach remote networks, which indicates that the DHCP server is not providing the default gateway (option 3). Without a default gateway, the client has no route to destinations outside its local subnet, so traffic to remote networks is dropped. The DHCP server must be configured to supply the router's IP address as the default gateway for clients to forward inter-network traffic.
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.
✗
DNS server option
Why it's wrong here
DNS affects name resolution, not basic routed connectivity.
When this WOULD be correct
In a different scenario where the question specifies that clients can access local resources but fail to resolve domain names, the DNS server option would be the correct answer. For example, if the client can ping local IPs but not external domains, the DNS configuration would be the likely issue.
✗
Lease time option
Why it's wrong here
Lease time controls duration, not path to remote networks.
When this WOULD be correct
In a different scenario, if a question asks about DHCP configurations affecting client connectivity specifically related to lease durations, a missing lease time option could lead to clients not being able to renew their IP addresses, thus causing connectivity issues.
✓
Default gateway option
Why this is correct
Without the correct gateway, off-subnet traffic fails.
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.
In a scenario where a question asks about a client that can reach local resources but cannot download files from a remote server, the TFTP server option could be missing or incorrectly configured. This would directly affect the client's ability to access TFTP services, making this option correct in that context.
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.
✓Default gateway optionCorrect answer▾
Why this is correct
Without the correct gateway, off-subnet traffic fails.
✗DNS server optionWrong answer — click to see why▾
Why this is wrong here
The DNS server option is not critical for basic connectivity to remote networks; it primarily affects name resolution. If a client can obtain an IP address but cannot reach remote networks, the issue is more likely related to the default gateway configuration.
★ When this WOULD be the correct answer
In a different scenario where the question specifies that clients can access local resources but fail to resolve domain names, the DNS server option would be the correct answer. For example, if the client can ping local IPs but not external domains, the DNS configuration would be the likely issue.
Why candidates choose this
Candidates may choose this option because they associate DNS with network connectivity issues, especially if they have encountered problems where name resolution failures caused access issues. This can lead to confusion about the role of DNS in overall network functionality.
✗Lease time optionWrong answer — click to see why▾
Why this is wrong here
The lease time option specifies how long a DHCP lease is valid, but it does not affect the ability to reach remote networks. Therefore, a missing or incorrect lease time would not directly cause connectivity issues.
★ When this WOULD be the correct answer
In a different scenario, if a question asks about DHCP configurations affecting client connectivity specifically related to lease durations, a missing lease time option could lead to clients not being able to renew their IP addresses, thus causing connectivity issues.
Why candidates choose this
Candidates may confuse the lease time option with overall network connectivity, thinking that if a client cannot reach remote networks, it could be due to lease issues rather than routing configurations.
✗TFTP server optionWrong answer — click to see why▾
Why this is wrong here
The TFTP server option is not necessary for a client to reach remote networks, as it primarily facilitates file transfers and does not impact routing or network accessibility. Therefore, its absence would not directly cause connectivity issues to remote networks.
★ When this WOULD be the correct answer
In a scenario where a question asks about a client that can reach local resources but cannot download files from a remote server, the TFTP server option could be missing or incorrectly configured. This would directly affect the client's ability to access TFTP services, making this option correct in that context.
Why candidates choose this
Candidates may be tempted by this option because TFTP is often associated with network services and can seem relevant when discussing connectivity issues, leading them to mistakenly believe it could impact overall network access.
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
Cisco often tests the distinction between DHCP options by presenting a symptom like 'can't reach the internet' and expecting candidates to recognize that the default gateway (option 3) is the critical missing piece, not DNS or lease time.
Detailed technical explanation
How to think about this question
DHCP option 3 (Router) is the standard way to assign a default gateway to clients; without it, the client's routing table lacks a default route (0.0.0.0/0). In Cisco IOS, the 'ip dhcp pool' configuration includes the 'default-router' command to set this option. A real-world scenario is when a DHCP server is on a different VLAN and the 'ip helper-address' command forwards DHCP broadcasts but the server's scope is missing the default gateway, leaving clients with local-only connectivity.
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 small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this 200-301 question in full detail.
Network Services and Security — This question tests Network Services and Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Default gateway option — The client can obtain an IP address but cannot reach remote networks, which indicates that the DHCP server is not providing the default gateway (option 3). Without a default gateway, the client has no route to destinations outside its local subnet, so traffic to remote networks is dropped. The DHCP server must be configured to supply the router's IP address as the default gateway for clients to forward inter-network traffic.
What should I do if I get this 200-301 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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Question Discussion
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