Which ACL type is used to deny traffic based on the source IP with a TTL parameter?

• A. Ns ACL
• B. SimpleACL
• C. SimpleACL with destIP
• D. Ns ACL with TTL

Answer: (B)

The key idea here is filtering traffic by the source IP with the simplest tool available. SimpleACL is designed for straightforward IP-based filtering: you specify the source IP (and you can add a destination IP if needed) and choose an action such as deny. When your goal is to block traffic based on where it’s coming from, this direct, minimal configuration is the most efficient and reliable approach.

The other options introduce more complexity or additional matching criteria. Using an ACL that involves a destination IP adds extra specificity we don’t need if the requirement is just source-origin filtering. An NS ACL type with TTL would be used only if you needed to match on the packet’s TTL value, which is a more advanced criterion than simply denying by source IP. So for denying traffic based on the source IP with a TTL parameter, the simplest, most appropriate match is provided by SimpleACL, making it the best choice.