The answer is to enable IPv6 unicast routing, configure the OSPFv3 process with a router-id, and activate OSPFv3 on the GigabitEthernet0/0 interface in area 0. This is correct because OSPFv3 for IPv6 requires a separate routing process and a mandatory 32-bit router-id to establish neighbor adjacencies, even though IPv6 addresses are used for routing; without a router-id, the OSPFv3 process cannot form a neighbor relationship. On the CCNA 200-301 v2 exam, this scenario tests your understanding that OSPFv3 configuration differs from OSPFv2—you must explicitly enter the `ipv6 router ospf` process configuration mode and assign a router-id, then enable OSPFv3 per interface with the `ipv6 ospf <process-id> area <area-id>` command. A common trap is forgetting the router-id or assuming OSPFv3 automatically uses an IPv6 address as the router-id, which it does not. To verify, use `show ospfv3 neighbor` to confirm the adjacency and `show ipv6 route ospf` to see the learned route. Memory tip: “OSPFv3 needs a 32-bit ID, not an IPv6 address—think of it as a legacy handshake for the new protocol.”
CCNA IP Routing Practice Question
This 200-301 practice question tests your understanding of ip routing. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Exhibit
R1# show running-config | section ipv6
ipv6 unicast-routing
!
interface GigabitEthernet0/0
ipv6 address 2001:db8:acad:1::1/64
no shutdown
!
interface Loopback0
ipv6 address 2001:db8:acad:1::100/64
no shutdown
!
end
R1# show ipv6 interface brief
GigabitEthernet0/0 [up/up]
FE80::1
2001:db8:acad:1::1
Loopback0 [up/up]
FE80::100
2001:db8:acad:1::100
You are connected to R1 via console. R1 and R2 are directly connected via their GigabitEthernet0/0 interfaces. Configure OSPFv3 for IPv6 on both routers so that the loopback0 interface on R2 (with IPv6 address 2001:db8:acad:2::1/64) is reachable from R1. Enable IPv6 unicast routing, enable OSPFv3 on the appropriate interfaces, and verify the neighbor adjacency and routing table. (Note: R2 already has OSPFv3 configured and is waiting for R1 to complete its configuration.)
R1# show running-config | section ipv6
ipv6 unicast-routing
!
interface GigabitEthernet0/0
ipv6 address 2001:db8:acad:1::1/64
no shutdown
!
interface Loopback0
ipv6 address 2001:db8:acad:1::100/64
no shutdown
!
end
R1# show ipv6 interface brief
GigabitEthernet0/0 [up/up]
FE80::1
2001:db8:acad:1::1
Loopback0 [up/up]
FE80::100
2001:db8:acad:1::100
A
Enable IPv6 unicast routing, configure OSPFv3 process with router-id, enable OSPFv3 on GigabitEthernet0/0 in area 0, and verify neighbor and route.
This is correct because OSPFv3 requires IPv6 unicast routing enabled globally, an OSPFv3 process with a router-id, and interface-level activation in an area. Verification confirms adjacency and route learning.
B
Enable IPv6 unicast routing, configure OSPFv2 process with router-id, enable OSPFv2 on GigabitEthernet0/0 in area 0, and verify neighbor and route.
Why wrong: This is incorrect because OSPFv2 is for IPv4, not IPv6. The question specifically asks for OSPFv3 for IPv6.
C
Enable IPv6 unicast routing, configure OSPFv3 process without a router-id, enable OSPFv3 on GigabitEthernet0/0 in area 0, and verify neighbor and route.
Why wrong: This is incorrect because OSPFv3 requires a router-id to establish neighbor adjacencies. Without a router-id, the OSPFv3 process will not form adjacencies.
D
Enable IPv6 unicast routing, configure OSPFv3 process with router-id, enable OSPFv3 on GigabitEthernet0/0 in area 0, but do not verify neighbor or route.
Why wrong: This is incorrect because verification is essential to confirm that the configuration is working. The question explicitly asks to verify the neighbor adjacency and routing table.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Enable IPv6 unicast routing, configure OSPFv3 process with router-id, enable OSPFv3 on GigabitEthernet0/0 in area 0, and verify neighbor and route.
The issue is that OSPFv3 process is not enabled on R1. To fix, first ensure IPv6 unicast routing is enabled (already done). Then configure OSPFv3 routing process with a process ID (e.g., 1) and router-id using the `ipv6 router ospf 1` command and `router-id` command. Then enable OSPFv3 on the GigabitEthernet0/0 interface with `ipv6 ospf 1 area 0`. Finally, verify with `show ospfv3 neighbor` to see R2's router ID (e.g., 2.2.2.2) and `show ipv6 route ospf` to see the route to 2001:db8:acad:2::/64.
Key principle: OSPF neighbour adjacency depends on matching area, hello/dead timers, network type, and authentication — IP reachability alone is not enough.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
Enable IPv6 unicast routing, configure OSPFv3 process with router-id, enable OSPFv3 on GigabitEthernet0/0 in area 0, and verify neighbor and route.
Why this is correct
This is correct because OSPFv3 requires IPv6 unicast routing enabled globally, an OSPFv3 process with a router-id, and interface-level activation in an area. Verification confirms adjacency and route learning.
Enable IPv6 unicast routing, configure OSPFv2 process with router-id, enable OSPFv2 on GigabitEthernet0/0 in area 0, and verify neighbor and route.
Why it's wrong here
This is incorrect because OSPFv2 is for IPv4, not IPv6. The question specifically asks for OSPFv3 for IPv6.
✗
Enable IPv6 unicast routing, configure OSPFv3 process without a router-id, enable OSPFv3 on GigabitEthernet0/0 in area 0, and verify neighbor and route.
Why it's wrong here
This is incorrect because OSPFv3 requires a router-id to establish neighbor adjacencies. Without a router-id, the OSPFv3 process will not form adjacencies.
✗
Enable IPv6 unicast routing, configure OSPFv3 process with router-id, enable OSPFv3 on GigabitEthernet0/0 in area 0, but do not verify neighbor or route.
Why it's wrong here
This is incorrect because verification is essential to confirm that the configuration is working. The question explicitly asks to verify the neighbor adjacency and routing table.
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.
✓Enable IPv6 unicast routing, configure OSPFv3 process with router-id, enable OSPFv3 on GigabitEthernet0/0 in area 0, and verify neighbor and route.Correct answer▾
Why this is correct
This is correct because OSPFv3 requires IPv6 unicast routing enabled globally, an OSPFv3 process with a router-id, and interface-level activation in an area. Verification confirms adjacency and route learning.
✗Enable IPv6 unicast routing, configure OSPFv2 process with router-id, enable OSPFv2 on GigabitEthernet0/0 in area 0, and verify neighbor and route.Wrong answer — click to see why▾
Why this is wrong here
OSPFv2 supports only IPv4; OSPFv3 is required for IPv6 routing.
Why candidates choose this
Candidates may confuse OSPFv2 and OSPFv3, especially if they are more familiar with IPv4 OSPF configuration.
✗Enable IPv6 unicast routing, configure OSPFv3 process without a router-id, enable OSPFv3 on GigabitEthernet0/0 in area 0, and verify neighbor and route.Wrong answer — click to see why▾
Why this is wrong here
OSPFv3 uses a 32-bit router-id, which must be manually configured or derived from an IPv4 address; without it, the process cannot operate.
Why candidates choose this
Candidates may think OSPFv3 can use IPv6 addresses as router-ids, but it still requires a router-id in dotted-decimal format.
✗Enable IPv6 unicast routing, configure OSPFv3 process with router-id, enable OSPFv3 on GigabitEthernet0/0 in area 0, but do not verify neighbor or route.Wrong answer — click to see why▾
Why this is wrong here
Verification commands like 'show ospfv3 neighbor' and 'show ipv6 route ospf' are necessary to ensure OSPFv3 is functioning correctly.
Why candidates choose this
Candidates may focus only on configuration steps and overlook the verification step, which is a common exam requirement.
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?”
Common exam traps
Common exam trap: OSPF can fail even when IP connectivity looks correct
OSPF neighbour formation depends on matching areas, timers, network type, authentication and passive-interface behaviour. Do not choose an answer only because the devices can ping.
Detailed technical explanation
How to think about this question
OSPF questions usually test the details that control adjacency and route selection. Read the neighbour state, area, router ID and interface configuration before deciding what is wrong.
KKey Concepts to Remember
OSPF neighbours must agree on key parameters.
Router ID selection can affect neighbour relationships and LSDB output.
OSPF cost influences the preferred path.
A route can appear in OSPF information but not become the installed route.
TExam Day Tips
→Check area mismatch first when OSPF adjacency fails.
→Review passive interfaces when a network is advertised but no neighbour forms.
→Use show ip ospf neighbor and show ip route clues carefully.
Key takeaway
OSPF neighbour adjacency depends on matching area, hello/dead timers, network type, and authentication — IP reachability alone is not enough.
Real-world example
How this comes up in practice
A network engineer at a university connects two campus buildings via a fibre link. Both routers run OSPF, but no adjacency forms — even though both routers can ping each other. The engineer finds one router is in area 0 and the other in area 1. OSPF adjacency requires matching area numbers, hello/dead timers, and network type. IP reachability alone is not enough.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this 200-301 question in full detail.
Review OSPF neighbour requirements — matching area type, hello and dead timers, network type, stub flags, and authentication. Study show ip ospf neighbor states (INIT, 2-WAY, FULL). Then practise related 200-301 OSPF questions on adjacency and route selection.
IP Routing — This question tests IP Routing — OSPF neighbours must agree on key parameters..
What is the correct answer to this question?
The correct answer is: Enable IPv6 unicast routing, configure OSPFv3 process with router-id, enable OSPFv3 on GigabitEthernet0/0 in area 0, and verify neighbor and route. — The issue is that OSPFv3 process is not enabled on R1. To fix, first ensure IPv6 unicast routing is enabled (already done). Then configure OSPFv3 routing process with a process ID (e.g., 1) and router-id using the `ipv6 router ospf 1` command and `router-id` command. Then enable OSPFv3 on the GigabitEthernet0/0 interface with `ipv6 ospf 1 area 0`. Finally, verify with `show ospfv3 neighbor` to see R2's router ID (e.g., 2.2.2.2) and `show ipv6 route ospf` to see the route to 2001:db8:acad:2::/64.
What should I do if I get this 200-301 question wrong?
Review OSPF neighbour requirements — matching area type, hello and dead timers, network type, stub flags, and authentication. Study show ip ospf neighbor states (INIT, 2-WAY, FULL). Then practise related 200-301 OSPF questions on adjacency and route selection.
What is the key concept behind this question?
OSPF neighbours must agree on key parameters.
About these practice questions
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These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. You are connected to R1. Configure OSPFv3 for IPv6 so that R1 and R2 can exchange IPv6 routes over their directly connected link. Enable IPv6 routing, assign OSPFv3 process and area on the interface, and verify that the neighbor adjacency forms and routes appear in the IPv6 routing table.
hard
✓ A.Enable IPv6 routing with 'ipv6 unicast-routing', configure OSPFv3 on the interface with 'ipv6 ospf 1 area 0', and verify with 'show ospfv3 neighbor' and 'show ipv6 route ospf'.
B.Enable IPv6 routing with 'ipv6 unicast-routing', configure OSPFv3 globally with 'router ospfv3 1' and 'router-id 1.1.1.1', then assign the interface to area 0 with 'ipv6 ospf 1 area 0'.
C.Enable IPv6 routing with 'ipv6 unicast-routing', configure OSPFv3 on the interface with 'ipv6 ospf 1 area 0', and verify with 'show ip ospf neighbor' and 'show ip route ospf'.
D.Enable IPv6 routing with 'ipv6 unicast-routing', configure OSPFv3 on the interface with 'ipv6 ospf 1 area 0', and verify with 'show ospfv3 neighbor' and 'show ipv6 route'.
Why A: Option A is correct because it includes enabling IPv6 routing with 'ipv6 unicast-routing', applying OSPFv3 to the interface using 'ipv6 ospf 1 area 0', and verifying with the correct OSPFv3-specific commands 'show ospfv3 neighbor' and 'show ipv6 route ospf'. Option B is incorrect because it adds a global 'router ospfv3 1' command, which is unnecessary; OSPFv3 can be configured directly on the interface without a global process. Option C is incorrect because it uses IPv4 OSPF verification commands 'show ip ospf neighbor' and 'show ip route ospf', which are not valid for OSPFv3. Option D is incorrect because although it uses the correct 'show ospfv3 neighbor', the 'show ipv6 route' command does not filter to OSPF-learned routes, so it displays all IPv6 routes rather than just OSPF routes.
Variation 2. You are connected to R1 via console. Configure OSPFv3 for IPv6 on R1 and R2 so that IPv6 loopback interfaces on both routers can communicate. R1's GigabitEthernet0/0 and R2's GigabitEthernet0/1 are directly connected. Ensure OSPFv3 is enabled on the correct interfaces and verify neighbors and routes.
hard
✓ A.Enable OSPFv3 on R1's GigabitEthernet0/0 and Loopback0, and on R2's GigabitEthernet0/1 and Loopback0.
B.Enable OSPFv3 only on the loopback interfaces of both routers.
C.Enable OSPFv3 on R1's GigabitEthernet0/0 and R2's GigabitEthernet0/1 only, without loopbacks.
D.Enable OSPFv3 on R1's Loopback0 and R2's GigabitEthernet0/1 only.
Why A: The issue is that OSPFv3 is not enabled on the interfaces. On R1, OSPFv3 must be enabled on GigabitEthernet0/0 (the link to R2) and Loopback0 (to advertise the loopback). On R2, OSPFv3 must be enabled on GigabitEthernet0/1 (the link to R1) and Loopback0. After enabling OSPFv3 on the correct interfaces, the neighbor adjacency forms and routes are exchanged.
Variation 3. You are connected to R1. Configure OSPFv3 for IPv6 on R1 and R2 so that they can exchange IPv6 routes. R1's GigabitEthernet0/0 is connected to R2's GigabitEthernet0/0. R1 has a loopback0 with IPv6 address 2001:db8:1::1/32, and R2 has a loopback0 with IPv6 address 2001:db8:2::2/32. Ensure OSPFv3 is enabled on both routers, the link interfaces are in area 0, and R1 learns the loopback route from R2.
hard
✓ A.Configure 'ipv6 ospf 1 area 0' under GigabitEthernet0/0 and Loopback0 on both routers.
B.Configure 'ipv6 router ospf 1' and then 'network 2001:db8:2::2/32 area 0' under the OSPFv3 process.
C.Configure 'ipv6 unicast-routing' and 'ipv6 ospf 1 area 0' under the global configuration.
D.Configure 'router ospf 1' and then 'ipv6 unicast-routing' under the OSPFv3 process.
Why A: The provided configuration enables OSPFv3 on the interfaces, which is necessary, but it does not set a router-id. OSPFv3 requires a router-id to form adjacencies. Without any IPv4 addresses configured, the router-id defaults to 0.0.0.0, preventing neighbor formation and route exchange. Therefore, a valid solution must also include a router-id command under the OSPFv3 process (e.g., 'ipv6 router ospf 1' followed by 'router-id X.X.X.X').
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