Applying a named ACL inbound You created a named ACL called 'Blocksales'. Which command correctly applies this ACL to packets entering interface Serial0?
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A(config)# ip access-group 110 in
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B(config-if)# ip access-group 110 in
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C(config-if)# ip access-group Blocksales in
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D(config-if)# blocksales ip access-list in
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E(config-if)# ip access-apply Blocksales in
Answer
Correct Answer: (config-if)# ip access-group Blocksales in
Explanation
Introduction / Context:Named ACLs offer readability and easier maintenance than numbered lists. The method to apply them to an interface is exactly the same as for numbered ACLs: use ip access-group with the ACL name and the direction (in or out) in interface configuration mode.
Given Data / Assumptions:
- A named IPv4 ACL called Blocksales exists.
- We want to apply it inbound on interface Serial0.
- Classic IOS syntax is in use.
Concept / Approach:
Command pattern: interface s0 then ip access-group Blocksales in. The keyword is identical for numbered or named IPv4 ACLs. IPv6 named ACLs use a different application command (ipv6 traffic-filter).
Step-by-Step Solution:
Enter interface configuration mode for Serial0.Apply the ACL: ip access-group Blocksales in.Verify with show ip interface serial 0.Observe counters with show access-lists Blocksales when traffic flows.Verification / Alternative check:
Use show run interface serial 0 to ensure the ACL is bound, then test with traffic from a blocked host to see counter increments.
Why Other Options Are Wrong:
- Options A and B reference numeric ACL 110; our ACL is named.
- Options D and E are not valid IOS command syntaxes.
Common Pitfalls:
- Applying the ACL in the wrong direction; “in” means packets entering the interface.
- Forgetting that ACL processing is top-down; order entries carefully.
Final Answer:
(config-if)# ip access-group Blocksales in