CCNA Network Infrastructure and Connectivity Practice Question
Which command enables IPv6 routing on a Cisco router?
⚠ Common exam trap
Be careful not to confuse interface-specific commands with global routing commands. Remember that enabling IPv6 globally requires a specific command.
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
✓
ipv6 unicast-routing
The global configuration command 'ipv6 unicast-routing' enables IPv6 forwarding on a Cisco router. 'ipv6 enable' is an interface-level command used to enable IPv6 on a specific interface, not globally. 'ip routing ipv6' and 'ipv6 route enable' are syntactically invalid commands that do not exist in Cisco IOS.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
ipv6 unicast-routing
Why this is correct
The global configuration command 'ipv6 unicast-routing' is the correct and required command to enable IPv6 routing on a Cisco router. It enables IPv6 packet forwarding on all interfaces and allows the router to route IPv6 traffic between networks. Without this command, the router will not forward IPv6 packets but will still process traffic explicitly addressed to itself.
- ✗
ipv6 enable
Why it's wrong here
'ipv6 enable' is an interface-level command that activates IPv6 processing on a single interface without assigning an IPv6 address. It does not enable IPv6 routing globally on the router. To route IPv6 packets between networks, you must issue the global command 'ipv6 unicast-routing' in global configuration mode.
When this WOULD be correct
In a scenario where the question asks for a command to enable IPv6 on an interface, such as 'Which command would you use to enable IPv6 on a specific interface?', 'ipv6 enable' would be the correct answer.
- ✗
ip routing ipv6
Why it's wrong here
'ip routing ipv6' is not valid Cisco IOS syntax. The command 'ip routing' is used to enable IPv4 routing, but there is no such command with 'ipv6' appended in that order. IPv6 routing is enabled with the separate global command 'ipv6 unicast-routing', so this option does not achieve the intended result.
When this WOULD be correct
If the exam question asked for a command related to configuring IPv6 routing protocols or managing IPv6 routes, 'ip routing ipv6' could be interpreted as a command for enabling IPv6 routing in that context, especially if it was framed around routing protocol configurations.
- ✗
ipv6 route enable
Why it's wrong here
The command 'ipv6 route enable' is not a valid Cisco IOS command. The correct global command to enable IPv6 routing is 'ipv6 unicast-routing'. Additionally, 'ipv6 route' is used for configuring static routes, not for enabling routing functionality, so this option is incorrect.
When this WOULD be correct
In a different scenario, if the question were about enabling a specific IPv6 routing protocol or feature that uses a command similar to 'ipv6 route enable', this option could be correct. For example, if the question asked about enabling a specific routing protocol that requires a similar command structure, it could be valid.
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.
✓ipv6 unicast-routingCorrect answer▾
Why this is correct
The global configuration command 'ipv6 unicast-routing' is the correct and required command to enable IPv6 routing on a Cisco router. It enables IPv6 packet forwarding on all interfaces and allows the router to route IPv6 traffic between networks. Without this command, the router will not forward IPv6 packets but will still process traffic explicitly addressed to itself.
✗ipv6 enableWrong answer — click to see why▾
Why this is wrong here
The 'ipv6 enable' command is used at the interface level to enable IPv6 processing on that specific interface, not to enable global IPv6 routing. Without 'ipv6 unicast-routing', the router will not forward IPv6 packets between interfaces even if IPv6 is enabled on them.
★ When this WOULD be the correct answer
In a scenario where the question asks for a command to enable IPv6 on an interface, such as 'Which command would you use to enable IPv6 on a specific interface?', 'ipv6 enable' would be the correct answer.
Why candidates choose this
Students often confuse 'ipv6 enable' with enabling IPv6 routing because the command name suggests enabling IPv6. However, it only configures IPv6 on an interface, not the routing process.
✗ip routing ipv6Wrong answer — click to see why▾
Why this is wrong here
The command 'ip routing ipv6' is not valid Cisco IOS syntax. The correct command to enable IPv4 routing is 'ip routing', and for IPv6 it is 'ipv6 unicast-routing'. Mixing the syntax leads to a syntax error.
★ When this WOULD be the correct answer
If the exam question asked for a command related to configuring IPv6 routing protocols or managing IPv6 routes, 'ip routing ipv6' could be interpreted as a command for enabling IPv6 routing in that context, especially if it was framed around routing protocol configurations.
Why candidates choose this
Test-takers might guess this command because it resembles 'ip routing' for IPv4, assuming a similar pattern for IPv6. However, Cisco uses a different keyword structure for IPv6.
✗ipv6 route enableWrong answer — click to see why▾
Why this is wrong here
'ipv6 route enable' is not a valid Cisco IOS command. The correct command to enable IPv6 routing is 'ipv6 unicast-routing'. This incorrect option may be confused with static route configuration using 'ipv6 route'.
★ When this WOULD be the correct answer
In a different scenario, if the question were about enabling a specific IPv6 routing protocol or feature that uses a command similar to 'ipv6 route enable', this option could be correct. For example, if the question asked about enabling a specific routing protocol that requires a similar command structure, it could be valid.
Why candidates choose this
The phrase 'route enable' sounds like it would enable routing, and 'ipv6 route' is a valid command for static routes, so students might incorrectly assume this command enables the routing process.
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
Routing Protocol Comparison
| Protocol | Metric | Max Hops | Algorithm | Type |
|---|---|---|---|---|
| RIP v2 | Hop count | 15 | Bellman-Ford | Distance vector |
| OSPF | Cost (bandwidth) | Unlimited | Dijkstra (SPF) | Link state |
| EIGRP | Composite metric | Unlimited | DUAL | Hybrid |
| IS-IS | Cost | Unlimited | Dijkstra | Link state |
| BGP | Policy / attributes | Unlimited | Path vector | Path vector |
RIP's 15-hop limit makes it unsuitable for large networks. OSPF and EIGRP dominate modern enterprise deployments.
Go deeper
Related to this question
Learn chapter
IPv6 Address Types
Key term
Interface
An interface is a point of connection or interaction between two systems, devices, or software components that allows them to exchange information or signals.
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.
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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.