The answer is a missing import map in VRF-B. This is the most likely cause because VRF route leaking using route-target import/export is a two-way process: the source VRF (VRF-A) must export its routes with a route-target export statement, and the destination VRF (VRF-B) must explicitly import those routes using a route-target import statement or an import map. Without the import map on VRF-B, the router’s control plane simply discards the leaked routes, even if VRF-A’s export configuration is correct. On the ENCOR 350-401 exam, this scenario tests your understanding of MPLS L3VPN and VRF-lite mechanics, often appearing as a trick where candidates assume a single export command is sufficient. A common trap is forgetting that import and export are independent; you can export from VRF-A without VRF-B ever receiving the routes. Memory tip: think of it like a locked door—export puts the key in the lock, but import turns it.
CCNP Virtualization Practice Question
This 350-401 practice question tests your understanding of virtualization. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A network engineer is troubleshooting a Cisco IOS-XE router that hosts multiple virtual routing and forwarding (VRF) instances. Users in VRF-A report they cannot reach a server in VRF-B. The engineer verifies that both VRFs have the correct routes and that the router has a route leaking configuration using route-target import/export. However, connectivity still fails. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The import map is missing in VRF-B.
Option D is correct because route leaking between VRFs using route-target import/export requires both an export configuration on the source VRF and an import configuration on the destination VRF. If VRF-B lacks an import map (or the route-target import statement), it will not accept the routes exported from VRF-A, even if VRF-A has the correct export configuration. This is a common misconfiguration in MPLS L3VPN or VRF-lite route leaking scenarios.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
The router does not have iBGP configured between the VRFs.
The route-target export is not configured in VRF-A.
Why it's wrong here
Export is configured as stated, but the import side is misconfigured.
✗
The router is using VRF-lite, which does not support route leaking.
Why it's wrong here
VRF-lite does support route leaking with proper configuration.
✓
The import map is missing in VRF-B.
Why this is correct
An import map is required to selectively import routes from VRF-A into VRF-B.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the misconception that route-target export alone is sufficient for route leaking, but the import configuration on the receiving VRF is equally mandatory.
Detailed technical explanation
How to think about this question
In Cisco IOS-XE, route leaking between VRFs using route-target import/export works by tagging routes with a route-target extended community on export and filtering incoming routes based on that community on import. The import map (configured under 'ip vrf VRF-B route-target import <value>') defines which route-target communities are accepted; without it, VRF-B's routing table will not contain the leaked routes. A real-world scenario is when an enterprise uses VRF-lite to separate guest and corporate networks and forgets to configure the import statement on the destination VRF, causing connectivity failures despite correct export on the source.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Virtualization — This question tests Virtualization — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The import map is missing in VRF-B. — Option D is correct because route leaking between VRFs using route-target import/export requires both an export configuration on the source VRF and an import configuration on the destination VRF. If VRF-B lacks an import map (or the route-target import statement), it will not accept the routes exported from VRF-A, even if VRF-A has the correct export configuration. This is a common misconfiguration in MPLS L3VPN or VRF-lite route leaking scenarios.
What should I do if I get this 350-401 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This 350-401 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 350-401 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.