CCNA IP Routing Practice Question
You are configuring a Cisco router that connects to an ISP via a serial link. The ISP has assigned the next-hop address 203.0.113.1 for all Internet-bound traffic. You need to ensure that the router forwards all traffic for unknown destinations to this next-hop, but you do not want to use a fully specified static route. Which command should you use?
⚠ Common exam trap
Candidates often confuse the ip default-gateway command with a default route; the former is for management access on non-routing devices, not for routing transit traffic.
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
✓
ip route 0.0.0.0 0.0.0.0 203.0.113.1
A default static route is configured with the destination network 0.0.0.0 and subnet mask 0.0.0.0, followed by the next-hop IP address. This matches all packets and is the correct way to direct unknown traffic to the ISP. The other options either create a host route, point to an interface without a next-hop, or use a command that does not affect the routing table on a router.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
ip route 0.0.0.0 0.0.0.0 203.0.113.1
Why this is correct
This command creates a default static route that matches all packets and forwards them to the specified next-hop address. It is the standard way to configure a default route when the exit interface is not specified, which is appropriate for multi-access networks like Ethernet. It meets the requirement without using a fully specified route.
- ✗
ip route 0.0.0.0 0.0.0.0 Serial0/0/0
Why it's wrong here
This command creates a default route pointing out an interface but does not specify a next-hop address. On a serial point-to-point link, this is valid, but the scenario requires using the next-hop address 203.0.113.1. Also, the question explicitly asks for a command that does not use a fully specified static route, but this is not fully specified; however, it does not use the next-hop as required.
- ✗
ip route 203.0.113.1 255.255.255.255 Serial0/0/0
Why it's wrong here
This is a host route to the ISP next-hop address via a specific interface, not a default route. It would only match traffic destined to 203.0.113.1 itself, not all unknown destinations. It does not fulfill the requirement of forwarding all Internet-bound traffic.
- ✗
ip default-gateway 203.0.113.1
Why it's wrong here
The ip default-gateway command is used on hosts or switches to set a default gateway for management traffic, but it does not enable routing on a router. On a router, this command is ineffective for forwarding transit traffic; it only sets a gateway for the device itself when IP routing is disabled. It does not create a default route in the routing table.
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
EIGRP Topology Table and DUAL
Key term
Route
A route is a path that data takes through a network from one device or network to another, determined by routing protocols and configured rules.
Key term
Subnet mask
A subnet mask is a 32-bit number that helps a computer or network device determine which part of an IP address identifies the network and which part identifies the host device on that network.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Cisco exam blueprint
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.