Cisco Certified Network Associate (CCNA) Practice Exam

Which command can be used to confirm that OSPF v3 interfaces are in the same subnet?

1. #show ipv6 ospf neighbor

2. #show ipv6 interface brief

3. #debug ipv6 ospf adj

4. #show ospf interface

The correct answer is: #show ipv6 interface brief

The command to confirm that OSPFv3 interfaces are in the same subnet is the one that displays a brief summary of all IPv6 interfaces on the router. This command will show the interface status, IPv6 address, and subnet prefix for each interface, allowing you to quickly identify if the interfaces participating in OSPFv3 are indeed within the same subnet. When configuring OSPF for IPv6 (OSPFv3), interfaces must be in the same subnet for successful neighbor adjacency and routing communication. The output from this command provides the necessary information to verify subnet configurations without diving into detailed settings on each interface. Other commands listed serve different purposes: one checks OSPF neighbor relationships, another shows detailed OSPF adjacency information, and the last one is typically related to OSPF for IPv4, not IPv6. Each of these can be useful in the troubleshooting and monitoring of OSPF operations, but they do not directly provide information about the subnet configuration of the interfaces.