Question 660
A distribution switch applies an ingress ACL to a routed SVI, but administrators expect it to block frames bridged only inside the same VLAN. Which ongoing operational safeguard best reduces the chance of recurrence?
Explanation
Correct Answer
This is a continuing control for the failure mode in which an L3 SVI ACL may not inspect traffic that never traverses that routed interface. It complements the immediate fix instead of relying on a one-off correction.
Incorrect Answers
That control is useful for a different failure, such as when a switch trunk's CRC error counters climb while application traffic degrades after a fiber transceiver change. It would leave the present failure mode insufficiently addressed.
That control is useful for a different failure, such as when a VSX downstream switch has an active multi-chassis LAG, but the primary and secondary peers disagree on the permitted client VLANs. It would leave the present failure mode insufficiently addressed.
That control is useful for a different failure, such as when an 802.1Q trunk carries VLAN 20 untagged on one end and tagged on the other, causing intermittent DHCP placement. It would leave the present failure mode insufficiently addressed.