Question 1hardmultiple choice
Full question →hardmultiple choiceObjective-mapped
A standard ACL and an extended ACL are both available for a design. Which requirement most strongly indicates that an extended ACL is needed?
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
The policy must distinguish traffic by destination, protocol, or port.
This is correct because those requirements need extended ACL granularity.
B
Distractor review
The policy needs to match only one source subnet.
This is wrong because source-only matching is exactly where a standard ACL may be enough.
C
Distractor review
The ACL must be placed near the destination.
This is wrong because placement guidance does not by itself determine the ACL type.
D
Distractor review
The network uses IPv6 instead of IPv4.
This is wrong because the underlying need here is still about match detail, not that distinction.
Common exam trap
Common exam trap: answer the scenario, not the keyword
A frequent exam trap is selecting ACL type based solely on placement or IP version rather than filtering requirements. Candidates often incorrectly choose an extended ACL just because the ACL must be near the destination or because the network uses IPv6. However, ACL placement is a deployment best practice, not a determinant of ACL type. Similarly, IPv6 networks use different ACL syntax but the same principle applies: the need to filter by destination, protocol, or port drives the choice of extended ACL. Misunderstanding this leads to incorrect answers that focus on placement or IP version instead of the core filtering granularity requirement.
Technical deep dive
How to think about this question
Access Control Lists (ACLs) are fundamental tools in Cisco networking used to filter traffic based on defined criteria. Standard ACLs filter traffic solely based on the source IP address, making them suitable for simple filtering tasks where only the origin of traffic matters. Extended ACLs provide much finer granularity by allowing filtering based on source and destination IP addresses, as well as protocol types (such as TCP, UDP, ICMP) and specific port numbers. This granularity enables network administrators to implement detailed security policies and traffic controls. When deciding between a standard and an extended ACL, the key factor is the level of detail required in the filtering policy. If the policy requires distinguishing traffic by destination IP, protocol type, or port number—for example, blocking HTTP traffic while allowing SSH—an extended ACL is necessary. Standard ACLs cannot differentiate beyond source IP, so they are insufficient for policies needing protocol or port-based filtering. Cisco best practices also recommend placing extended ACLs close to the source of traffic to minimize unnecessary traffic on the network. A common exam trap involves confusing ACL placement with ACL type. While extended ACLs are often placed near the source and standard ACLs near the destination, placement alone does not dictate the ACL type. Another pitfall is assuming IPv6 usage mandates extended ACLs; the deciding factor remains the filtering granularity. Practically, extended ACLs enable precise traffic control, which is essential for enforcing complex security policies in modern networks, making them indispensable when detailed traffic discrimination is required.
KKey Concepts to Remember
- Standard ACLs filter traffic based solely on the source IP address and cannot distinguish by destination, protocol, or port.
- Extended ACLs filter traffic by source and destination IP addresses, protocol types, and port numbers, providing detailed traffic control.
- The choice between standard and extended ACLs depends primarily on the required filtering granularity in the security policy.
- Extended ACLs are necessary when the policy must differentiate traffic by destination IP, protocol, or port to enforce precise rules.
- ACL placement near source or destination is a deployment best practice but does not determine whether to use standard or extended ACLs.
- IPv6 networks require ACLs that support IPv6 addresses, but the filtering granularity rules for standard versus extended ACLs remain the same.
- Misinterpreting ACL placement or IP version as the deciding factor for ACL type is a common exam trap.
- Effective ACL design involves matching the ACL type to the filtering criteria to ensure proper traffic control and security enforcement.
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?
Standard ACLs filter traffic based solely on the source IP address and cannot distinguish by destination, protocol, or port.
What is the correct answer to this question?
The correct answer is: The policy must distinguish traffic by destination, protocol, or port. — An extended ACL is most strongly indicated when the policy must match not just on source address, but also on destination, protocol, or port information. In practical terms, if the requirement is something like “block HTTP but allow SSH” or “deny traffic to one server but not another,” a standard ACL is too limited because it mainly matches only the source. This question is about choosing the right ACL type for the matching requirement. Granularity points to extended ACLs.
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.
Discussion
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