300-410 ENARSI: Implementing Cisco Enterprise Advanced Routing and ServicesDemo

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QuestionQ26

Infrastructure Services

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Refer to the exhibit. An engineer applies a prefix-list filter that blocks most network 10 prefixes rather than permitting them. Which action resolves the issue?

  • A Modify the ip prefix-list EIGRP seq 20 permit 10.0.0.0/8 ge 9 command.
  • B Modify the ip prefix-list EIGRP seq 10 permit 10.0.0.0/8 le 9 command.
  • C Modify the ip prefix-list EIGRP seq 20 permit 0.0.0.0/0 le 32 command.
  • D Modify the ip prefix-list EIGRP seq 10 permit 10.0.0.0/8 le 32 command.
Explanation

A prefix-list entry without ge or le matches only the exact prefix length, so permit 10.0.0.0/8 permits only the /8 aggregate. Configuring le 32 permits that aggregate and every more-specific prefix within 10.0.0.0/8; the later deny entry can continue to block all other routes. Cisco documents that le sets the maximum matched prefix length and that, when used alone, the range begins with the prefix length in the entry.

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