Implementing Cisco IP Routing (CCNP ROUTE, legacy) — Question 167

For security purposes, an IPv6 traffic filter was configured under various interfaces on the local router. However, shortly after implementing the traffic filter,
OSPFv3 neighbor adjacencies were lost. What caused this issue?

Answer options

• A. The traffic filter is blocking all ICMPv6 traffic.
• B. The global anycast address must be added to the traffic filter to allow OSPFv3 to work properly.
• C. The link-local addresses that were used by OSPFv3 were explicitly denied, which caused the neighbor relationships to fail.

Correct answer:

Explanation

The correct answer is C because OSPFv3 relies on link-local addresses for neighbor discovery and adjacency formation. If these addresses are blocked by the traffic filter, OSPFv3 cannot establish or maintain neighbor relationships. Options A and B are incorrect as they do not directly address the specific requirement of link-local addresses for OSPFv3 operation.