300-440 Question 211
Single answerAn enterprise network administrator is troubleshooting a router's security configuration. The router is configured with Control Plane Policing (CoPP) to protect against malicious traffic targeting the control plane. However, the administrator notices that legitimate management traffic from a trusted source is being dropped. What is the most likely cause of the issue?
- A
The CoPP policy is misconfigured and is incorrectly classifying the trusted traffic as malicious.
- B
The access control list (ACL) used in the CoPP policy does not include the trusted source IP address.
- C
The trusted source is incorrectly configured to send traffic to a different control plane interface.
- D
The CoPP policy is disabled and is not actively protecting the control plane.
Show answer and explanation
Correct answer: B
Explanation
The issue lies within the ACL used in the CoPP policy. If the ACL does not explicitly permit the trusted source IP address, the CoPP policy will drop that traffic since it assumes anything not explicitly permitted is malicious. This is a common troubleshooting scenario when implementing router security features like CoPP.
- A. Incorrect.
This is a plausible cause because if the CoPP policy misclassifies trusted traffic, it can drop it. However, the issue is more likely due to specific ACL misconfiguration rather than general policy misclassification.
- B. Correct.
This is the correct answer. If the ACL used in the CoPP policy does not explicitly permit the trusted source IP address, the traffic from the trusted source will be dropped.
- C. Incorrect.
This is unlikely because trusted sources are typically configured correctly unless there is a separate configuration issue. The problem described is specific to CoPP.
- D. Incorrect.
This is incorrect because the question states that CoPP is actively dropping traffic, which means the policy is enabled and functional.