CCNA Network Infrastructure and Connectivity Practice Question
Which TWO of the following are essential IPv4 host parameters that must be correctly configured for a host to communicate with devices on remote networks?
⚠ Common exam trap
Cisco often tests the misconception that a DNS server address is a mandatory host parameter for remote communication, but DNS is only a name-resolution service and not required for IP-level connectivity.
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
✓
Default gateway
The default gateway is the IP address of the router interface on the local subnet; when a host needs to communicate with a device on a remote network, it must forward packets to the default gateway because the destination is not reachable locally. The subnet mask is equally essential because the host uses it (along with its own IP address) to determine whether a destination IP address is on the same local network or a remote network; without a correctly configured subnet mask, the host cannot make this determination and may misroute traffic. DNS server address is only for name resolution and is not required for IP-level connectivity, MAC address is a Layer 2 address already present on the NIC, and hostname is a local identifier irrelevant to routing.
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 address
Why it's wrong here
A DNS server address is not a mandatory IPv4 host parameter because hosts can communicate directly using numeric IP addresses without ever performing name resolution. DNS only translates human-friendly domain names into IP addresses, and if you know or hard-code the destination IP, no DNS server is needed for connectivity. For example, pinging 8.8.8.8 works without DNS, but pinging google.com would fail if no DNS server is configured.
- ✓
Default gateway
Why this is correct
The default gateway is the router interface that resides on the host's local subnet and serves as the exit point for all traffic destined to remote networks. When a host determines a destination is not on the same subnet, it encapsulates the packet with the gateway's Layer 2 address and forwards it there, relying on the router to route it onward. Without a default gateway, the host will discard any packet intended for a different network, because it has no way to send traffic off its local segment, making this parameter essential for basic internetwork communication.
- ✓
Subnet mask
Why this is correct
The subnet mask defines which portion of the IPv4 address is the network identifier and which portion is the host identifier, enabling the host to perform the AND operation to decide if a destination is local or remote. A host with an IP address but no subnet mask cannot correctly determine whether an outgoing packet should be sent directly to the destination on the same link or sent to a router for off-subnet delivery. Even a valid IP address is useless without a proper mask, as it would lead to incorrect local/remote decisions and prevent communication beyond that immediate LAN.
- ✗
MAC address
Why it's wrong here
A MAC address is a Layer 2 hardware address used for local delivery, but it is not a configurable IPv4 host parameter in the same sense; hosts automatically have a MAC address from the NIC.
- ✗
Host name
Why it's wrong here
A host name is simply an administrative label assigned to the device for identification and management purposes; it has no operational role in IPv4 packet forwarding. Unlike IP address, subnet mask, or default gateway, a host name is optional because networking equipment and protocols rely on numeric IP addresses and MAC addresses, not device labels, to move traffic. You can assign multiple devices the same host name or change it at any time without affecting their ability to send or receive IP packets, confirming it is not a required configuration element.
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 gatewayCorrect answer▾
Why this is correct
The default gateway is the router interface that resides on the host's local subnet and serves as the exit point for all traffic destined to remote networks. When a host determines a destination is not on the same subnet, it encapsulates the packet with the gateway's Layer 2 address and forwards it there, relying on the router to route it onward. Without a default gateway, the host will discard any packet intended for a different network, because it has no way to send traffic off its local segment, making this parameter essential for basic internetwork communication.
✗DNS server addressWrong answer — click to see why▾
Why this is wrong here
A host can communicate using IP addresses directly without DNS. DNS is a service, not a mandatory parameter for routing.
✗MAC addressWrong answer — click to see why▾
Why this is wrong here
MAC addresses are not manually configured as part of IPv4 host parameters (they are burned into the NIC). The question asks for IPv4 host parameters that must be configured.
✗Host nameWrong answer — click to see why▾
Why this is wrong here
Host names are used for identification and can be resolved via DNS, but they are not essential for the host to send or receive IP packets.
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
Default gateway
A default gateway is a network device, typically a router, that acts as the exit point for traffic from a local network to other networks, including the internet.
Key term
Name Server
A name server is a specialized server that translates human-readable domain names into machine-readable IP addresses so that 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.