Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
What is the main reason extended ACLs are often placed closer to the source of the traffic being filtered?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Best answer
To stop unwanted traffic earlier and avoid carrying it farther through the network.
This is correct because extended ACLs are commonly placed near the source for efficiency and control.
B
Distractor review
Because extended ACLs can function only on source interfaces.
This is wrong because extended ACLs are not limited to source interfaces only.
C
Distractor review
Because standard ACLs must always be placed near the destination instead.
This is misleading because the question is asking why extended ACLs are commonly placed near the source.
D
Distractor review
Because ACL placement has no effect on network efficiency.
This is wrong because earlier filtering can reduce unnecessary traffic movement.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A frequent exam trap is confusing the placement rules for extended ACLs with those for standard ACLs. Some candidates mistakenly think extended ACLs should be placed near the destination like standard ACLs or believe ACL placement does not affect network efficiency. This misunderstanding leads to incorrect answers because extended ACLs filter on multiple criteria and are most effective when placed near the traffic source to block unwanted packets early. Ignoring this principle can cause unnecessary traffic to consume bandwidth and processing resources downstream, which is a critical concept tested on the CCNA exam.
Technical deep dive
How to think about this question
Access Control Lists (ACLs) are fundamental Cisco security tools used to filter traffic based on defined criteria such as source and destination IP addresses, protocols, and ports. Extended ACLs provide granular control by allowing filtering based on multiple parameters, including source and destination IP addresses, protocol types (TCP, UDP, ICMP), and port numbers. This specificity enables network administrators to precisely control which traffic is permitted or denied, enhancing security and traffic management within a network. The placement of extended ACLs is critical for network efficiency and security. Best practice dictates placing extended ACLs as close to the source of the traffic as possible. This approach stops unwanted traffic early, preventing it from traversing the network unnecessarily and consuming bandwidth. By filtering traffic near the source, the network reduces load on intermediate devices and links, improving overall performance and security posture. This contrasts with standard ACLs, which filter only by source IP and are typically placed near the destination to avoid inadvertently blocking legitimate traffic. A common exam trap is misunderstanding ACL placement rules and confusing extended ACLs with standard ACLs. Candidates may incorrectly believe extended ACLs must be placed near the destination or that ACL placement does not impact network efficiency. In practice, placing extended ACLs near the source optimizes resource use and security. Misplacement can lead to inefficient traffic flow and potential security gaps. Understanding this principle is essential for both passing the CCNA exam and designing effective Cisco networks.
KKey Concepts to Remember
- Extended ACLs filter traffic based on multiple criteria including source IP, destination IP, protocol type, and port numbers, providing granular traffic control.
- Placing extended ACLs near the source of traffic prevents unwanted packets from traversing the network, conserving bandwidth and reducing load on intermediate devices.
- Standard ACLs filter only on source IP addresses and are typically placed near the destination to avoid blocking legitimate traffic prematurely.
- Early filtering with extended ACLs improves network efficiency by reducing unnecessary forwarding of denied traffic across multiple network segments.
- ACL placement directly impacts network performance and security, making strategic placement essential for effective traffic management.
- Misplacing extended ACLs near the destination can lead to inefficient bandwidth use and increased processing on intermediate devices.
- Cisco best practices recommend placing extended ACLs close to the traffic source to maximize filtering effectiveness and network resource optimization.
- Understanding the difference in placement strategies between standard and extended ACLs is critical for CCNA exam success and practical network design.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A router learns the same prefix from both OSPF and EIGRP. Which route is installed by default?
Question 2
A router shows this output: R1#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 10.1.1.2 1 FULL/DR 00:00:34 192.168.12.2 GigabitEthernet0/0 10.1.1.3 1 2WAY/DROTHER 00:00:39 192.168.12.3 GigabitEthernet0/0 Which statement is correct?
Question 3
What is the OSPF metric called?
Question 4
A non-root switch has two uplinks toward the root bridge. One path has a lower total STP cost than the other. What role will the lower-cost uplink have?
Question 5
A router interface applies this ACL inbound: 10 deny tcp any any eq 80 20 permit ip any any A user reports that web browsing to a server by IP address fails, but ping works. Which statement best explains the behavior?
Question 6
A router learns route 198.51.100.0/24 from OSPF with AD 110 and also has a static route to the same prefix configured with AD 150. Which route is installed?
FAQ
Questions learners often ask
What does this 200-301 question test?
Extended ACLs filter traffic based on multiple criteria including source IP, destination IP, protocol type, and port numbers, providing granular traffic control.
What is the correct answer to this question?
The correct answer is: To stop unwanted traffic earlier and avoid carrying it farther through the network. — Extended ACLs are often placed close to the source so unwanted traffic is stopped earlier in the path. In practical terms, that conserves bandwidth and reduces unnecessary forwarding of traffic that will be denied anyway. Because extended ACLs can match more specific conditions such as source, destination, and protocol, they are especially useful early in the traffic path. This is a standard ACL placement principle. The goal is not just security logic, but efficient use of the network as well.
What should I do if I get this 200-301 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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