1. Understanding the ACL Rule
The rule:
rule 5 deny source 100.0.12.0 0.0.0.255
* Blocks traffic originating from 100.0.12.0/24 (Host B's network).
* This means any packet sent from Host B to Host A will be blocked.
2. Applying the ACL to the Correct Interfaces
* Option A: Applied inbound on GE0/0/1 # Blocks packets from Host B before reaching Host A. #
* Option B: Applied inbound on GE0/0/2 # Blocks packets from Host A before reaching Host B. #
3. Why Other Options Are Incorrect
* Option C (GigabitEthernet0/0/3):
* Interface GE0/0/3 is not connected to Host A or Host B, so applying ACL here is meaningless.
* Option D (Outbound on GE0/0/1):
* Outbound filtering is less efficient than inbound filtering because it blocks traffic after routing.
4. Correct Approach to Prevent Communication
To completely block communication between Host A and Host B, we must:# Block inbound traffic on GE0/0
/1 (Host A's interface)# Block inbound traffic on GE0/0/2 (Host B's interface) Conclusion:
* The correct choices are A and B because they block inbound traffic at the correct interfaces.
* Options C and D are incorrect because they apply ACL rules to the wrong interfaces or use inefficient filtering.
References:# HCIA-Datacom V1.0 Certification Guide, Chapter 5: ACL Configuration