Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
Which statement best explains why a DHCP client typically also needs a subnet mask in addition to an IP address?
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 subnet mask tells the host which destinations are local and which require a gateway.
This is correct because the mask defines local network scope.
B
Distractor review
The subnet mask encrypts the host’s traffic.
This is wrong because subnet masks do not provide encryption.
C
Distractor review
The subnet mask replaces the need for DNS.
This is wrong because subnet masks do not perform hostname resolution.
D
Distractor review
The subnet mask creates a trunk between the host and switch.
This is wrong because subnet masks are unrelated to trunking.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A frequent exam trap is selecting answers that confuse the subnet mask’s purpose with unrelated network functions. For example, some might incorrectly believe the subnet mask encrypts traffic or replaces DNS, which is false. Another tempting mistake is assuming the subnet mask configures physical link features like VLAN trunking. These misconceptions arise because candidates sometimes conflate IP layer addressing with other network services or link-layer operations. The correct understanding is that the subnet mask strictly defines the local network boundary, enabling the host to decide whether to send traffic directly or via the default gateway.
Technical deep dive
How to think about this question
The subnet mask is a fundamental component of IP addressing that defines which portion of an IP address refers to the network and which part refers to the host. It works by masking bits of the IP address to separate network bits from host bits, allowing devices to understand the size and boundaries of their local subnet. This distinction is critical because it determines how a host communicates within its local network and how it sends traffic to remote networks. When a DHCP client receives an IP address, it also needs the subnet mask to apply this rule. The host uses the subnet mask to compare its own IP address with the destination IP address. If the destination is within the same subnet, the host sends traffic directly using ARP to resolve the MAC address. If the destination is outside the subnet, the host forwards the traffic to its configured default gateway for routing. This decision-making process is essential for proper IP communication and network segmentation. A common exam trap is confusing the subnet mask’s role with unrelated functions such as encryption, DNS resolution, or VLAN trunking. The subnet mask strictly defines network boundaries and does not provide security or name resolution. Misunderstanding this can lead to incorrect answers. Practically, if a host lacks the correct subnet mask, it may fail to communicate properly, causing network connectivity issues even if the IP address is valid.
KKey Concepts to Remember
- A DHCP client requires a subnet mask to determine the network portion and host portion of its assigned IP address.
- The subnet mask enables a host to decide whether a destination IP address is on the local subnet or requires routing through a default gateway.
- Without a subnet mask, a host cannot correctly perform ARP requests for local addresses or forward packets to the gateway for remote addresses.
- DHCP provides not only the IP address but also the subnet mask as part of the essential IP configuration parameters.
- The subnet mask does not provide security features such as encryption or replace services like DNS.
- Hosts use the subnet mask to segment IP addresses into logical networks, which is fundamental for IP routing and communication.
- Incorrect assumptions about the subnet mask’s function can lead to communication failures between hosts on different networks.
- The subnet mask is unrelated to physical link-layer functions such as VLAN trunking or switch port 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.
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 DHCP client requires a subnet mask to determine the network portion and host portion of its assigned IP address.
What is the correct answer to this question?
The correct answer is: The subnet mask tells the host which destinations are local and which require a gateway. — A host needs the subnet mask so it can determine which destinations are local and which are remote. In plain language, the IP address identifies the host, but the mask tells the host how large the local network is. Without that information, the host cannot reliably decide when to ARP locally and when to send traffic to the default gateway. This is a core host-configuration concept because correct communication depends on more than having an address alone. The correct answer is the one focused on local-versus-remote decision making.
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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