Question 723 of 2,152

NetFlow and Flexible NetFlow →hardMultiple ChoiceObjective-mapped

Quick Answer

The answer is that the route-map LEAK is also applied to the flow monitor as a filter, and the flow monitor’s match statement is misconfigured to deny the route, preventing the route from being leaked. This occurs because Flexible NetFlow can use a route-map as a traffic filter for the flow monitor, and if that same route-map is used for VRF route leaking, the router applies the match logic in both contexts. When the flow monitor’s match ip address prefix-list statement includes a deny for the 10.0.0.0/8 prefix, it blocks the route from being considered for the leak, even though the prefix-list permits it in the route-map. On the Cisco CCNP ENARSI 300-410 exam, this tests your understanding of how Flexible NetFlow interacts with VRF-aware features and the subtle conflict that arises when shared route-maps are used for both monitoring and route leaking. A common trap is assuming the flow monitor only collects statistics without affecting routing behavior. Memory tip: “A shared map can trap a leak—if the monitor denies, the leak will sleep.”

300-410 NetFlow and Flexible NetFlow Practice Question

This 300-410 practice question tests your understanding of netflow and flexible netflow. 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 VRF-aware network uses route leaking between VRF A and VRF B. After configuring Flexible NetFlow to monitor traffic in VRF A, some routes that were previously leaked to VRF B disappear. Router R1 has: ip route vrf A 10.0.0.0 255.0.0.0 Null0. route-map LEAK permit 10 match ip address prefix-list GLOBAL. The prefix-list GLOBAL permits 10.0.0.0/8. The flow monitor is applied to the VRF A interface. What is the root cause?

Question 1hardmultiple choice

Read the full network assurance explanation →

A
The flow monitor is configured with a match ip address prefix-list that references the same prefix-list as the route-map, but the flow monitor's action is to drop packets matching that prefix, causing the route to be withdrawn.
Why wrong: Flexible NetFlow does not drop packets; it only monitors them.
B
The route-map LEAK is also applied to the flow monitor as a filter, and the flow monitor's match statement is misconfigured to deny the route, preventing the route from being leaked.
If the same route-map is used for both route leaking and as a flow filter, and the route-map has a deny statement (or the flow monitor interprets it differently), the route may not be leaked. However, a more precise explanation is that the flow monitor can use a route-map to filter flows, and if that route-map denies the prefix, the flow monitor will not monitor it, but it could also affect the route leaking if the route-map is shared.
C
The VRF A interface has a flow monitor applied that uses a flow record with the 'vrf' field, causing the router to ignore the route leaking configuration.
Why wrong: The 'vrf' field in a flow record does not affect routing.
D
The route leaking configuration requires a next-hop that is not reachable due to the flow monitor consuming bandwidth.
Why wrong: Bandwidth consumption is not the issue here.

Full breakdown with real-world context →

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

✓

The route-map LEAK is also applied to the flow monitor as a filter, and the flow monitor's match statement is misconfigured to deny the route, preventing the route from being leaked.

Flexible NetFlow can be applied per VRF, but if the flow monitor is configured with a match statement that includes the VRF ID or if the flow record includes the 'vrf' field, it might cause the router to process packets differently. However, the issue is that the route-map used for leaking is also being used by the flow monitor, or the flow monitor is inadvertently matching on the route-map. The correct answer is that the flow monitor is configured with a match ip address prefix-list statement that references the same prefix-list used in the route-map, but the flow monitor is applied in the input direction, causing the router to evaluate the prefix-list for every packet, which may interfere with the route leaking process. More specifically, if the flow monitor uses a match ip address prefix-list that includes a deny statement, it could affect the route-map's operation. But the most likely root cause is that the flow monitor is configured with a flow record that includes the 'ipv4 destination prefix' field, and the router is using the same prefix-list for both purposes, causing a conflict. Actually, the correct answer is that the route-map LEAK is also used by the flow monitor as a filter, and the flow monitor's match statement is inadvertently denying the route.

Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.

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 flow monitor is configured with a match ip address prefix-list that references the same prefix-list as the route-map, but the flow monitor's action is to drop packets matching that prefix, causing the route to be withdrawn.
Why it's wrong here
Flexible NetFlow does not drop packets; it only monitors them.
✓
The route-map LEAK is also applied to the flow monitor as a filter, and the flow monitor's match statement is misconfigured to deny the route, preventing the route from being leaked.
Why this is correct
If the same route-map is used for both route leaking and as a flow filter, and the route-map has a deny statement (or the flow monitor interprets it differently), the route may not be leaked. However, a more precise explanation is that the flow monitor can use a route-map to filter flows, and if that route-map denies the prefix, the flow monitor will not monitor it, but it could also affect the route leaking if the route-map is shared.
Related concept
Static NAT maps one inside address to one outside address.
✗
The VRF A interface has a flow monitor applied that uses a flow record with the 'vrf' field, causing the router to ignore the route leaking configuration.
Why it's wrong here
The 'vrf' field in a flow record does not affect routing.
✗
The route leaking configuration requires a next-hop that is not reachable due to the flow monitor consuming bandwidth.
Why it's wrong here
Bandwidth consumption is not the issue here.

Common exam traps

Common exam trap: NAT rules depend on direction and matching traffic

NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.

Detailed technical explanation

How to think about this question

NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.

KKey Concepts to Remember

Static NAT maps one inside address to one outside address.
PAT allows many inside hosts to share one public address using ports.
Inside local and inside global describe the private and translated addresses.
NAT ACLs identify traffic for translation, not always security filtering.

TExam Day Tips

Identify inside and outside interfaces first.
Check whether the scenario needs static NAT, dynamic NAT or PAT.
Do not confuse NAT matching ACLs with normal packet-filtering intent.

Key takeaway

NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.

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.

Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related 300-410 NAT questions on configuration and troubleshooting.

Related 300-410 practice-question pages

Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.

Layer 3 Technologies practice questions

Practise 300-410 questions linked to Layer 3 Technologies.

EIGRP Troubleshooting practice questions

Practise 300-410 questions linked to EIGRP Troubleshooting.

OSPF Troubleshooting (v2/v3) practice questions

Practise 300-410 questions linked to OSPF Troubleshooting (v2/v3).

BGP Troubleshooting practice questions

Practise 300-410 questions linked to BGP Troubleshooting.

Route Redistribution practice questions

Practise 300-410 questions linked to Route Redistribution.

Policy-Based Routing (PBR) practice questions

Practise 300-410 questions linked to Policy-Based Routing (PBR).

VRF-Lite practice questions

Practise 300-410 questions linked to VRF-Lite.

Route Maps and Route Filtering practice questions

Practise 300-410 questions linked to Route Maps and Route Filtering.

Administrative Distance practice questions

Practise 300-410 questions linked to Administrative Distance.

Route Summarization practice questions

Practise 300-410 questions linked to Route Summarization.

Bidirectional Forwarding Detection (BFD) practice questions

Practise 300-410 questions linked to Bidirectional Forwarding Detection (BFD).

VPN Technologies practice questions

Practise 300-410 questions linked to VPN Technologies.

Practice this exam

Start a free 300-410 practice session

Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.

10 questions 20 questions 30 questions 50 questions Timed 30

300-410 practice-test guide →Study guide →Browse all practice tests

FAQ

Questions learners often ask

What does this 300-410 question test?

NetFlow and Flexible NetFlow — This question tests NetFlow and Flexible NetFlow — Static NAT maps one inside address to one outside address..

What is the correct answer to this question?

The correct answer is: The route-map LEAK is also applied to the flow monitor as a filter, and the flow monitor's match statement is misconfigured to deny the route, preventing the route from being leaked. — Flexible NetFlow can be applied per VRF, but if the flow monitor is configured with a match statement that includes the VRF ID or if the flow record includes the 'vrf' field, it might cause the router to process packets differently. However, the issue is that the route-map used for leaking is also being used by the flow monitor, or the flow monitor is inadvertently matching on the route-map. The correct answer is that the flow monitor is configured with a match ip address prefix-list statement that references the same prefix-list used in the route-map, but the flow monitor is applied in the input direction, causing the router to evaluate the prefix-list for every packet, which may interfere with the route leaking process. More specifically, if the flow monitor uses a match ip address prefix-list that includes a deny statement, it could affect the route-map's operation. But the most likely root cause is that the flow monitor is configured with a flow record that includes the 'ipv4 destination prefix' field, and the router is using the same prefix-list for both purposes, causing a conflict. Actually, the correct answer is that the route-map LEAK is also used by the flow monitor as a filter, and the flow monitor's match statement is inadvertently denying the route.

What should I do if I get this 300-410 question wrong?

What is the key concept behind this question?

Static NAT maps one inside address to one outside address.

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 →

How Courseiva writes practice questions · Editorial policy

Keep practising

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.

Loading comments…

This 300-410 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 300-410 exam.