350-401 Question 570
Single answerA network administrator has implemented Control Plane Policing (CoPP) on a Cisco router to protect the control plane from excessive traffic. However, after applying the CoPP policy, the administrators are unable to establish an SSH session with the router, while other control plane protocols (EIGRP, OSPF, and BGP) are functioning normally. Which of the following is the MOST likely cause of the issue?
- A
The SSH traffic is not explicitly permitted in the CoPP policy.
- B
The CoPP policy is incorrectly classifying EIGRP, OSPF, and BGP traffic as SSH traffic.
- C
The CoPP policy is dropping all traffic that exceeds a predefined rate limit for SSH.
- D
The CoPP policy does not support SSH traffic.
Show answer and explanation
Correct answer: A
Explanation
Control Plane Policing (CoPP) requires explicit classification and permission for management protocols like SSH. If SSH traffic is not explicitly allowed in the CoPP policy, it will be dropped as part of the default deny-all behavior of CoPP. In this scenario, other protocols like EIGRP, OSPF, and BGP are functioning, so the issue is most likely that SSH traffic was accidentally omitted from the CoPP policy.
- A. Correct.
SSH traffic must be explicitly permitted in the CoPP policy. If not explicitly allowed, it will be dropped by default, causing the administrators to lose access to the router via SSH.
- B. Incorrect.
This is unlikely as EIGRP, OSPF, and BGP are functioning normally, which indicates they are properly classified and permitted in the CoPP policy.
- C. Incorrect.
While CoPP enforces rate limits, this issue would only occur if SSH traffic exceeded the configured limit. However, there is no indication of traffic exceeding the rate limit in this scenario.
- D. Incorrect.
This is incorrect because CoPP does support SSH traffic. The issue is related to how the CoPP policy is configured, not its capabilities.