- A
Add 'permit icmp any any' to access-list 150 to include ICMP in the COPP-CORE class.
Correct. Adding ICMP to the ACL would match it in the COPP-CORE class and apply the lower 64000 bps policer, providing better protection.
- B
Change the class-default police rate to 64000 bps to match the COPP-CORE rate.
Why wrong: Incorrect. While that would lower the rate for ICMP, it would also affect all other unclassified traffic. Better to specifically classify ICMP.
- C
Add a second class-map for ICMP and apply a separate policer.
Why wrong: Incorrect. That would work but is not the simplest fix. The question asks what is missing, and the simplest answer is to add ICMP to the existing ACL.
- D
The configuration is complete; ICMP is not a significant control-plane threat.
Why wrong: Incorrect. ICMP echo requests can be used for control-plane attacks, so they should be rate-limited.
Quick Answer
The answer is to add 'permit icmp any any' to access-list 150 so that ICMP traffic is matched by the COPP-CORE class. Without this entry, ICMP packets fall into the class-default, where they are policed at 128,000 bps—a rate that is often too generous to effectively mitigate a control-plane attack, such as a ping flood. On the Cisco CCNP ENARSI 300-410 exam, this question tests your understanding of how CoPP class-maps rely on ACLs to selectively police critical protocols; a common trap is assuming the default class provides adequate protection for all traffic types. The key insight is that CoPP works by explicitly classifying sensitive control-plane protocols—like BGP, LDP, and ICMP—into a higher-priority class with a lower police rate, while leaving less critical traffic in the default. A useful memory tip: "If it talks to the control plane, it needs its own ACL line—don't let ICMP fall through the default crack."
300-410 Control Plane Policing (CoPP) Practice Question
This 300-410 practice question tests your understanding of control plane policing (copp). This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Consider the following CoPP configuration:
access-list 150 permit tcp any any eq 179 access-list 150 permit udp any any eq 646
! class-map match-all COPP-CORE match access-group 150 ! policy-map COPP-POLICY
class COPP-CORE
police 64000 conform-action transmit exceed-action drop
class class-default
police 128000 conform-action transmit exceed-action drop ! control-plane service-policy input COPP-POLICY
What is missing from this configuration to also protect against ICMP-based control-plane attacks?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Add 'permit icmp any any' to access-list 150 to include ICMP in the COPP-CORE class.
The ACL only matches BGP (TCP 179) and LDP (UDP 646). ICMP is not included, so ICMP traffic falls into class-default and is only limited to 128000 bps, which may be too high for protection.
Key principle: ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Add 'permit icmp any any' to access-list 150 to include ICMP in the COPP-CORE class.
- ✗
Change the class-default police rate to 64000 bps to match the COPP-CORE rate.
Why it's wrong here
Incorrect. While that would lower the rate for ICMP, it would also affect all other unclassified traffic. Better to specifically classify ICMP.
- ✗
Add a second class-map for ICMP and apply a separate policer.
- ✗
The configuration is complete; ICMP is not a significant control-plane threat.
Why it's wrong here
Incorrect. ICMP echo requests can be used for control-plane attacks, so they should be rate-limited.
Common exam traps
Common exam trap: ACLs stop at the first match
ACLs are processed top to bottom. The first matching entry wins, and an implicit deny usually exists at the end.
Detailed technical explanation
How to think about this question
ACL questions test precision: source, destination, protocol, port and direction. A generally correct ACL can still fail if it is applied on the wrong interface or in the wrong direction.
KKey Concepts to Remember
- Standard ACLs match source addresses.
- Extended ACLs can match source, destination, protocol and ports.
- The first matching ACL entry is used.
- There is usually an implicit deny at the end.
TExam Day Tips
- Check inbound versus outbound direction.
- Read the ACL from top to bottom.
- Look for a broader permit or deny above the intended line.
Key takeaway
ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.
Real-world example
How this comes up in practice
A security administrator must allow nursing staff to reach a patient records server while blocking access from the guest Wi-Fi VLAN. After applying an extended ACL, traffic is still blocked from nursing workstations. The ACL was applied outbound instead of inbound on the wrong interface. Questions like this test ACL direction and placement rules.
What to study next
Got this wrong? Here's your next step.
Review ACL processing order, placement rules (standard near destination, extended near source), and inbound vs outbound direction. Study wildcard masks and implicit deny. Then practise related 300-410 ACL questions on filtering logic and placement.
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Control Plane Policing (CoPP) — study guide chapter
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FAQ
Questions learners often ask
What does this 300-410 question test?
Control Plane Policing (CoPP) — This question tests Control Plane Policing (CoPP) — Standard ACLs match source addresses..
What is the correct answer to this question?
The correct answer is: Add 'permit icmp any any' to access-list 150 to include ICMP in the COPP-CORE class. — The ACL only matches BGP (TCP 179) and LDP (UDP 646). ICMP is not included, so ICMP traffic falls into class-default and is only limited to 128000 bps, which may be too high for protection.
What should I do if I get this 300-410 question wrong?
Review ACL processing order, placement rules (standard near destination, extended near source), and inbound vs outbound direction. Study wildcard masks and implicit deny. Then practise related 300-410 ACL questions on filtering logic and placement.
What is the key concept behind this question?
Standard ACLs match source addresses.
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Last reviewed: Jun 18, 2026
This 300-410 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 300-410 exam.
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