hardMultiple ChoiceObjective-mapped
300-410 Practice Question: Router R1 is leaking a summary route 10.0.0.0/8…
Router R1 is leaking a summary route 10.0.0.0/8 from VRF-A into the global routing table, but hosts in the global table cannot reach subnet 10.1.1.0/24 within VRF-A. R1 configuration: ip vrf VRF-A, rd 100:1, route-target export 100:1, route-target import 100:1. Interface Gig0/0 in VRF-A has ip address 10.1.1.1 255.255.255.0. The leaking is done via route-map: route-map LEAK permit 10, match ip address prefix-list SUMMARY, set global. Prefix-list SUMMARY permits 10.0.0.0/8. What is the root cause?
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 summary route 10.0.0.0/8 is being installed in the global table, but the more specific route 10.1.1.0/24 is not leaked, causing traffic to be dropped.
The summary route 10.0.0.0/8 covers the more specific subnet 10.1.1.0/24, but the route-map only leaks the summary, not the specific. When the global table has the summary, traffic to 10.1.1.0/24 is forwarded based on the summary, but since the specific route is not leaked, the packet may be dropped or sent to a null interface if the summary points to a discard. The issue is that the summary route does not provide reachability to the specific subnet because the specific route is not leaked.
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 summary route 10.0.0.0/8 is being installed in the global table, but the more specific route 10.1.1.0/24 is not leaked, causing traffic to be dropped.
Why this is correct
Correct: The summary lacks the specific route; traffic to 10.1.1.0/24 matches the summary but may be discarded if the summary points to null or is not resolved.
- ✗
The route-map should use match ip address prefix-list SPECIFIC instead of SUMMARY.
Why it's wrong here
Incorrect: The intent is to leak a summary, but the specific route also needs to be leaked or the summary must point to a valid next-hop.
- ✗
The VRF must have a default route to reach the global table.
Why it's wrong here
Incorrect: The issue is about leaking from VRF to global, not the other direction.
- ✗
The prefix-list should permit 10.1.1.0/24 only.
Why it's wrong here
Incorrect: The summary is intended, but it fails to provide reachability to the specific subnet.
Visual reference
Go deeper
Related to this question
Learn chapter
OSPF Route Summarization and Filtering
Key term
BGP Prefix Filtering
BGP Prefix Filtering is the practice of controlling which network routes (prefixes) a router accepts or advertises to its BGP neighbors, preventing unwanted or harmful routes from spreading across the internet.
Key term
MPLS Layer 3 VPN
A technology that uses Multiprotocol Label Switching to create secure, scalable virtual private networks that connect multiple sites at the network layer, where the service provider manages routing between customer sites.
About these practice questions
This 300-410 question is part of Courseiva's 1,966-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.