This 300-410 practice question tests your understanding of ipv6 traffic filtering and urpf. Examine the command output carefully: the correct answer depends on what the output actually shows, not on general recall alone. 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 runs the following command on Router R1:
R1# show ipv6 interface gigabitethernet 0/0
GigabitEthernet0/0 is up, line protocol is up IPv6 is enabled, link-local address is FE80::1 Global unicast address(es): 2001:DB8:1:1::1, subnet is 2001:DB8:1:1::/64 Joined group address(es): FF02::1 FF02::2 ICMP redirects are enabled ICMP unreachables are enabled ND DAD is enabled, number of DAD attempts: 1 ND reachable time is 30000 milliseconds ND advertised reachable time is 0 milliseconds ND advertised retransmit interval is 1000 milliseconds ND router advertisements are sent every 200 seconds ND router advertisements live for 1800 seconds Hosts use stateless autoconfig for addresses. IPv6 uRPF: strict mode (drop invalid packets) Inbound access list: FILTER-IPv6
Based on this output, which two features are configured on this interface?
uRPF in strict mode and inbound IPv6 ACL
Both are clearly shown in the output.
uRPF in loose mode and outbound IPv6 ACL
Why wrong: uRPF is strict, and the ACL is inbound.
uRPF disabled and inbound IPv6 ACL
Why wrong: uRPF is enabled.
uRPF in strict mode and outbound IPv6 ACL
Why wrong: The ACL is inbound.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
uRPF in strict mode and inbound IPv6 ACL
The output shows 'IPv6 uRPF: strict mode (drop invalid packets)' and 'Inbound access list: FILTER-IPv6', confirming that unicast Reverse Path Forwarding in strict mode and an inbound IPv6 ACL are both configured on the interface. Strict uRPF verifies that the source address of incoming packets has a matching route in the FIB pointing back to the same interface, dropping packets that fail this check. The inbound ACL filters traffic before any routing decision, as indicated by the 'Inbound access list' line.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
uRPF in strict mode and inbound IPv6 ACL
Why this is correct
Both are clearly shown in the output.
Related concept
Read the scenario before looking for a memorised answer.
uRPF in loose mode and outbound IPv6 ACL
Why it's wrong here
uRPF is strict, and the ACL is inbound.
uRPF disabled and inbound IPv6 ACL
Why it's wrong here
uRPF is enabled.
uRPF in strict mode and outbound IPv6 ACL
Why it's wrong here
The ACL is inbound.
Common exam traps
Cisco often tests the distinction between strict and loose uRPF modes, and the trap here is that candidates may overlook the 'Inbound access list' line and assume the ACL is outbound, or confuse the uRPF mode with the ACL direction.
Detailed technical explanation
Strict uRPF is commonly used to mitigate source IP address spoofing on customer-facing interfaces where the network topology is symmetric and routes are stable; it requires a matching FIB entry with the same incoming interface. In contrast, loose uRPF only checks that a route to the source exists in the FIB, regardless of the interface, making it suitable for asymmetric routing scenarios. The 'ND DAD is enabled' line also indicates Duplicate Address Detection is active, which is unrelated to uRPF but often appears in the same show command output.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
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
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
IPv6 Traffic Filtering and uRPF — study guide chapter
Learn the concepts, then practise the questions
IPv6 Traffic Filtering and uRPF practice questions
Targeted practice on this topic area only
All 300-410 questions
2,152 questions across all exam domains
Cisco CCNP ENARSI 300-410 study guide
Full concept coverage aligned to exam objectives
300-410 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Practise 300-410 questions linked to Layer 3 Technologies.
Practise 300-410 questions linked to EIGRP Troubleshooting.
Practise 300-410 questions linked to OSPF Troubleshooting (v2/v3).
Practise 300-410 questions linked to BGP Troubleshooting.
Practise 300-410 questions linked to Route Redistribution.
Practise 300-410 questions linked to Policy-Based Routing (PBR).
Practise 300-410 questions linked to VRF-Lite.
Practise 300-410 questions linked to Route Maps and Route Filtering.
Practise 300-410 questions linked to Administrative Distance.
Practise 300-410 questions linked to Route Summarization.
Practise 300-410 questions linked to Bidirectional Forwarding Detection (BFD).
Practise 300-410 questions linked to VPN Technologies.
Practice this exam
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
IPv6 Traffic Filtering and uRPF — This question tests IPv6 Traffic Filtering and uRPF — Read the scenario before looking for a memorised answer..
The correct answer is: uRPF in strict mode and inbound IPv6 ACL — The output shows 'IPv6 uRPF: strict mode (drop invalid packets)' and 'Inbound access list: FILTER-IPv6', confirming that unicast Reverse Path Forwarding in strict mode and an inbound IPv6 ACL are both configured on the interface. Strict uRPF verifies that the source address of incoming packets has a matching route in the FIB pointing back to the same interface, dropping packets that fail this check. The inbound ACL filters traffic before any routing decision, as indicated by the 'Inbound access list' line.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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 →
Last reviewed: Jun 24, 2026
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.
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.