| Explanation & Hint:
If Cisco Express Forwarding (CEF) is disabled on a router, it affects how the router handles routing and the use of the routing table, but it does not inherently change the way static routes are configured or applied. Here’s what happens in the context of the provided options:
- Serial point-to-point interfaces will require fully specified static routes to avoid routing inconsistencies. This is not specifically related to CEF being disabled. Fully specified static routes (routes that specify both the next-hop IP address and the exit interface) can be used to avoid certain routing issues, but this is generally independent of CEF’s status.
- It will not perform recursive lookups. Disabling CEF does not prevent the router from performing recursive lookups. Recursive lookups are a fundamental part of routing, where the router needs to find how to reach a next-hop IP address. This is still required with or without CEF.
- Static routes that use an exit interface will be unnecessary. This is incorrect. Static routes can specify either a next-hop IP address or an exit interface, and this is still true whether CEF is enabled or not.
- Ethernet multiaccess interfaces will require fully specified static routes to avoid routing inconsistencies. This option is the most plausible effect when CEF is disabled. CEF optimizes the routing process, including how multiaccess interfaces handle packets. Without CEF, there could be inconsistencies or additional overhead in the routing process on multiaccess interfaces, and fully specifying static routes (with both the next-hop IP address and the exit interface) could help alleviate potential issues.
Therefore, the most accurate statement in the context of CEF being disabled is that Ethernet multiaccess interfaces may require fully specified static routes to avoid routing inconsistencies. |