CCNA Network Infrastructure and Connectivity Practice Question
Which TWO statements correctly describe the configuration and verification of IPv4 and IPv6 parameters for host connectivity, including default gateway, DNS, and subnet masks?
⚠ Common exam trap
Cisco often tests the misconception that IPv6 hosts require DHCPv6 for address assignment, when in fact SLAAC is a common and valid method, and the question's wording 'can only' is the trap that eliminates Option C.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The default gateway must be on the same subnet as the host's IP address.
A host's default gateway must be on the same subnet to be reachable at Layer 2; otherwise, a circular dependency occurs. Option D is correct because the 'ipconfig /all' command displays both IPv4 and IPv6 configuration details, including IP address, subnet mask, default gateway, and DNS servers. Option A is wrong because the subnet mask determines the network and host portions of an IP address, not the DNS server address. Option C is wrong because IPv6 hosts can obtain their IP address via SLAAC, DHCPv6, or static configuration; the phrase 'can only' makes it incorrect. Option E is wrong because the default gateway must be reachable (on the same subnet) and configured with an IP address that belongs to a router interface on that subnet, not just any IP address.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The subnet mask determines the DNS server address used by the host.
Why it's wrong here
The subnet mask is used to partition the IP address into network and host portions, determining whether traffic is local or remote, and is not related to DNS configuration. DNS server addresses are learned via DHCP, statically, or via IPv6 RDNSS (Router Advertisement options), and are never derived from the subnet mask.
- ✓
The default gateway must be on the same subnet as the host's IP address.
Why this is correct
For a host to deliver a frame to the default gateway, the gateway's IP must be in the same network/subnet as the host's interface, because the host uses ARP (or NDP for IPv6) to resolve the gateway's MAC address on the local link. If the gateway were on a different subnet, the host would not be able to reach it without another router on the local segment.
- ✗
IPv6 hosts can only obtain their IP address via DHCPv6.
Why it's wrong here
IPv6 supports SLAAC (Stateless Address Autoconfiguration) using router advertisements, which allows a host to derive its address from the prefix and its own interface ID without DHCPv6. DHCPv6 is used for stateful or additional parameters, but is not mandatory.
- ✓
The command 'ipconfig /all' displays both IPv4 and IPv6 configuration details.
Why this is correct
On Windows, ipconfig /all enumerates every adapter and provides a full listing of IPv4 and IPv6 settings, including addresses, subnet masks, default gateways, and DNS servers, so it is a valid way to view both protocol stacks. It also shows DHCP and autoconfiguration details for each interface.
- ✗
A host can reach any remote network if its default gateway is configured with any IP address.
Why it's wrong here
Merely assigning any IP address to a default gateway is insufficient because the configured gateway must be within the host's subnet for ARP/NDP resolution to succeed. If the IP is on a different subnet, the host will not attempt ARP and will not send the frame; additionally, the gateway device must have IP forwarding enabled and a route to the destination network to actually relay the traffic.
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.
✓The default gateway must be on the same subnet as the host's IP address.Correct answer▾
Why this is correct
For a host to deliver a frame to the default gateway, the gateway's IP must be in the same network/subnet as the host's interface, because the host uses ARP (or NDP for IPv6) to resolve the gateway's MAC address on the local link. If the gateway were on a different subnet, the host would not be able to reach it without another router on the local segment.
✗The subnet mask determines the DNS server address used by the host.Wrong answer — click to see why▾
Why this is wrong here
The subnet mask is used to determine the network portion of an IP address and the host portion, not the DNS server address. DNS server addresses are configured separately, either manually or via DHCP.
Why candidates choose this
Students might confuse the subnet mask with other configuration parameters, thinking it influences DNS server assignment because both are part of IP configuration.
✗IPv6 hosts can only obtain their IP address via DHCPv6.Wrong answer — click to see why▾
Why this is wrong here
IPv6 hosts can obtain their IP address via Stateless Address Autoconfiguration (SLAAC), which does not require DHCPv6. DHCPv6 is optional and used for stateful configuration or to provide additional parameters.
Why candidates choose this
Students familiar with IPv4 DHCP might assume IPv6 also requires a similar server-based address assignment, overlooking SLAAC as an alternative.
✗A host can reach any remote network if its default gateway is configured with any IP address.Wrong answer — click to see why▾
Why this is wrong here
The default gateway must be on the same subnet as the host's IP address; otherwise, the host cannot send Ethernet frames to it because the gateway's MAC address would not be reachable via ARP. An arbitrary IP address would not work.
Why candidates choose this
Students might think any IP address can serve as a default gateway, not realizing the necessity of Layer 2 adjacency for frame delivery.
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?”
Visual reference
Quick reference
IPv4 Address Class Summary
| Class | First Octet Range | Default Mask | Networks | Hosts per Network |
|---|---|---|---|---|
| A | 1–126 | /8 (255.0.0.0) | 126 | 16,777,214 |
| B | 128–191 | /16 (255.255.0.0) | 16,384 | 65,534 |
| C | 192–223 | /24 (255.255.255.0) | 2,097,152 | 254 |
| D | 224–239 | N/A | Multicast groups | — |
| E | 240–255 | N/A | Reserved / experimental | — |
127.x.x.x is reserved for loopback. Modern networks use CIDR (classless) rather than classful addressing.
Go deeper
Related to this question
Learn chapter
IPv4 Addressing and Address Classes
Key term
Internet Protocol
Internet Protocol (IP) is the set of rules that governs how data is addressed, routed, and sent from one device to another across networks, including the internet.
Key term
DNS
DNS is the system that translates human-friendly domain names like example.com into machine-readable IP addresses so computers can find each other on a network.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 200-301 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 200-301 exam.