Multiple choice

Refer to the exhibit. ACL 120 is configured inbound on the serial0/0/0 interface on router R1, but the hosts on network 172.11.10.0/24 are able to telnet to network 10.10.0.0/16. On the basis of the provided configuration, what should be done to remedy the problem?

  1. Apply the ACL outbound on the serial0/0/0 interface on router R1.

  2. Apply the ACL outbound on the FastEthernet0/0 interface on router R1.

  3. Include the established keyword at the end of the first line in the ACL.

  4. Include a statement in the ACL to deny the UDP traffic that originates from 172.11.10.0/24 network.
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A Correct answer
Explanation

ACLs applied inbound on an interface filter traffic entering that interface. Since hosts on 172.11.10.0/24 can still telnet to 10.10.0.0/16, the traffic isn't passing through the serial0/0/0 interface where the ACL is applied inbound. Applying the ACL outbound (on serial0/0/0) would filter traffic leaving R1 toward the 172.11.10.0 network. Applying it on FastEthernet0/0 (B) would be incorrect since that's a different interface.

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