Cisco
300-415 · Question #98
300-415 Question #98: Real Exam Question with Answer & Explanation
The correct answer is C: 0.0.0.0/0 le 16. The prefix-list entry '0.0.0.0/0 le 16' matches all IP prefixes that are subnets of 0.0.0.0/0 with a prefix length up to and including /16, effectively matching all prefixes from /0 through /16.
Policies
Question
An engineer is configuring a list that matches all IP prefixes with lengths from /1 to /16 in a centralized control policy. Which list accomplishes this task?
Options
- A0.0.0.0/1 le 16
- B0.0.0.0/0 ge 1
- C0.0.0.0/0 le 16
- D0.0.0.0/16 ge 1
Explanation
The prefix-list entry '0.0.0.0/0 le 16' matches all IP prefixes that are subnets of 0.0.0.0/0 with a prefix length up to and including /16, effectively matching all prefixes from /0 through /16.
Common mistakes.
- A. 0.0.0.0/1 le 16 restricts the base to /1, which would miss prefixes in the upper half of the IP address space that fall under 128.0.0.0/1.
- B. 0.0.0.0/0 ge 1 matches all prefixes from /1 to /32, which is far broader than the intended /1 to /16 range.
- D. 0.0.0.0/16 ge 1 is an invalid combination because 'ge' must be greater than or equal to the base prefix length (/16), making this match only /16 through /32, not /1 to /16.
Concept tested. Cisco SD-WAN centralized policy prefix-list ge/le matching
Topics
#Centralized Control Policy#IP Prefix Lists#Prefix Length Matching#SD-WAN Policies
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