The following is the output information of a router. Which of the following statements is correct?

Question

Options

• AThe community attribute value carried by the destination network segment 1.1.1.0/24 is no-export, indicating that the routing entry cannot be advertised to any BGP neighbors
• BThe community attribute value carried by the destination network segment 5.1.1.0/24 is no-advertise, indicating that the routing entry cannot be advertised to any other BGP neighbors
• CThe community attribute value carried by the destination network segment 1.1.1.0/24 is no-export, indicating that the routing entry cannot be advertised to BGP neighbors
• DThe community attribute value carried by the destination network segment 5.1.1.0/24 is no-advertise, indicating that the routing entry cannot be advertised outside the local AS

• A
  5% (1)
• B
  84% (16)
• C
  11% (2)

Explanation

Option B is correct because the BGP no-advertise community instructs a router to not send that route to any BGP neighbor - neither IBGP peers within the AS nor EBGP peers outside it. This is the most restrictive of the well-known community values.

Why the distractors are wrong:

• A is wrong because no-export does not block all BGP neighbors - it only prevents advertisement to EBGP peers (outside the local AS); IBGP peers within the same AS can still receive the route.
• C makes the same factual error as A, incorrectly implying no-export blocks all BGP neighbors rather than just EBGP ones.
• D swaps the definitions: "cannot be advertised outside the local AS" is the behavior of no-export, not no-advertise.

Memory tip: Think of the names literally - no-**advertise** kills ALL advertisement (to every neighbor), while no-**export** only stops the route from being exported beyond the AS boundary. If you mix them up, remember: Export = leave the AS; Advertise = tell anyone.

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