CCNA IP Routing Practice Question
Which command correctly configures an IPv6 default route using next-hop address 2001:db8:1::1?
⚠ Common exam trap
Be cautious about the syntax order and the correct representation of the IPv6 default route prefix.
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 route ::/0 2001:db8:1::1
The correct IPv6 default route uses the prefix ::/0 with the command 'ipv6 route ::/0'. Option B is wrong because 'ip route' is used for IPv4 routes, not IPv6. Option C uses 'ipv6 default-route', which is not a valid Cisco IOS command. Option D sets the management default gateway for IPv4 only and does not insert a route into the IPv6 routing table.
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 route ::/0 2001:db8:1::1
Why this is correct
The IOS global configuration command `ipv6 route` is the valid method to install a static IPv6 route, and the network prefix `::/0` is the IPv6 default route because it matches all destination addresses. Specifying `2001:db8:1::1` as the next hop tells the router to forward all unmatched IPv6 traffic to that neighbor. This is the exact syntax Cisco IOS uses for an IPv6 default route.
- ✗
ip route :: 2001:db8:1::1
Why it's wrong here
The `ip route` command operates on the IPv4 routing table, so it expects an IPv4 destination prefix in dotted-decimal notation and an IPv4 next-hop address, not the IPv6 prefix `::`. Even if the syntax were adjusted, Cisco IOS does not allow mixing the IPv4 `ip route` command with IPv6 addresses, and `::` is not a valid IPv4 prefix. This would be rejected by the parser as an invalid address family.
When this WOULD be correct
In a question specifically asking for an IPv4 default route configuration, where the next-hop address is also in IPv4 format, option B would be correct. For example, if the question stated to configure a default route using an IPv4 address like 192.168.1.1, then 'ip route 0.0.0.0 192.168.1.1' would be the right command.
- ✗
ipv6 default-route 2001:db8:1::1
Why it's wrong here
The command `ipv6 default-route` does not exist in Cisco IOS because there is no such keyword; the only way to define an IPv6 default route is with `ipv6 route ::/0`. This phrase is a common confusion with other protocol concepts like `default-information originate` or IPv4's `ip default-network`. Since the router will reject this command as invalid, it cannot install any default route.
When this WOULD be correct
If the exam question specifically asked for the command to configure a default route in a different context, such as using a specific vendor's proprietary syntax that recognizes 'ipv6 default-route', then this option would be correct.
- ✗
ip default-gateway 2001:db8:1::1
Why it's wrong here
The `ip default-gateway` command is used on Layer 3 switches to provide a management fallback gateway when IP routing is disabled, or on hosts to set a single default gateway; it is not a routing protocol command and does not program an IPv6 route. On a proper router, a default gateway is derived from the routing table, and a default route must be explicitly configured with `ipv6 route ::/0`. Therefore, this command would only set a gateway for management traffic, not forward IPv6 packets.
When this WOULD be correct
If the question were focused on configuring a default gateway for a Layer 2 switch in a small network environment, where no Layer 3 routing is involved, then 'ip default-gateway 2001:db8:1::1' would be the correct command to set the gateway for the switch to reach other networks.
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 route ::/0 2001:db8:1::1Correct answer▾
Why this is correct
The IOS global configuration command `ipv6 route` is the valid method to install a static IPv6 route, and the network prefix `::/0` is the IPv6 default route because it matches all destination addresses. Specifying `2001:db8:1::1` as the next hop tells the router to forward all unmatched IPv6 traffic to that neighbor. This is the exact syntax Cisco IOS uses for an IPv6 default route.
✗ip route :: 2001:db8:1::1Wrong answer — click to see why▾
Why this is wrong here
The command 'ip route :: 2001:db8:1::1' uses the IPv4 command structure 'ip route' instead of the IPv6-specific 'ipv6 route'. Additionally, the prefix '::' is not the correct notation for the default route; IPv6 uses '::/0'.
★ When this WOULD be the correct answer
In a question specifically asking for an IPv4 default route configuration, where the next-hop address is also in IPv4 format, option B would be correct. For example, if the question stated to configure a default route using an IPv4 address like 192.168.1.1, then 'ip route 0.0.0.0 192.168.1.1' would be the right command.
Why candidates choose this
Students may confuse the IPv4 default route command 'ip route 0.0.0.0 0.0.0.0' with IPv6, incorrectly assuming 'ip route ::' is equivalent. The similarity in syntax can lead to this mistake.
✗ipv6 default-route 2001:db8:1::1Wrong answer — click to see why▾
Why this is wrong here
The command 'ipv6 default-route 2001:db8:1::1' is not a valid Cisco IOS command. The correct syntax for an IPv6 default route is 'ipv6 route ::/0 <next-hop>'. There is no 'default-route' keyword in IPv6 routing configuration.
★ When this WOULD be the correct answer
If the exam question specifically asked for the command to configure a default route in a different context, such as using a specific vendor's proprietary syntax that recognizes 'ipv6 default-route', then this option would be correct.
Why candidates choose this
The phrase 'default-route' sounds intuitive and similar to 'default-gateway' or 'default route', making it tempting for those who guess the command syntax without knowing the exact IOS command.
✗ip default-gateway 2001:db8:1::1Wrong answer — click to see why▾
Why this is wrong here
The 'ip default-gateway' command is used for IPv4 default gateway configuration on hosts or switches in Layer 2 mode, not for configuring a routed default route on a router. For IPv6, the equivalent is 'ipv6 route ::/0'.
★ When this WOULD be the correct answer
If the question were focused on configuring a default gateway for a Layer 2 switch in a small network environment, where no Layer 3 routing is involved, then 'ip default-gateway 2001:db8:1::1' would be the correct command to set the gateway for the switch to reach other networks.
Why candidates choose this
Students may recall that 'ip default-gateway' sets a default route on a switch and incorrectly assume it works for IPv6 on a router. The term 'default-gateway' is commonly associated with default routes.
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?”
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OSPFv3 Single-Area Configuration for IPv6
Key term
Default route
A default route is a catch-all routing entry that tells a network device where to send packets when no specific route matches the destination address.
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.
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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.