350-501 Architecture Practice Question
A service provider uses BGP communities to influence routing policies. An administrator wants to prevent a specific prefix from being advertised to any external AS. Which BGP community should be applied?
⚠ Common exam trap
Cisco often tests the distinction between NO_EXPORT and NO_ADVERTISE, where candidates mistakenly choose NO_ADVERTISE because they think 'no advertisement' means 'no external advertisement,' but NO_ADVERTISE blocks all advertisements (including iBGP), while NO_EXPORT only blocks eBGP advertisements.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
NO_EXPORT
The NO_EXPORT community (well-known community 0xFFFFFF01) tells the router not to advertise the prefix to any external BGP peer (eBGP), but allows it to be advertised within the same AS (iBGP). This matches the requirement to prevent the prefix from being advertised to any external AS, as NO_EXPORT is specifically designed to keep routes confined to the local autonomous system.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
NO_ADVERTISE
Why it's wrong here
NO_ADVERTISE prevents advertisement to any peer, including iBGP, which is too restrictive.
- ✗
INTERNET
Why it's wrong here
INTERNET community does not affect advertisement.
- ✗
LOCAL_AS
Why it's wrong here
LOCAL_AS prevents advertisement to external peers but allows within the confederation; it is not the standard community for this purpose.
- ✗
NONE
Why it's wrong here
NONE is not a valid standard community.
- ✓
NO_EXPORT
Why this is correct
NO_EXPORT prevents advertisement to any eBGP peer, which is exactly what is needed.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 350-501 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 350-501 exam.