- A
Configure the bfd interval command under the interface.
Correct. The bfd interval command enables BFD on the interface and sets the timers.
- B
Configure the ip ospf bfd command under the interface.
Correct. This command enables BFD support for OSPF on that specific interface.
- C
Configure the bfd neighbor command under global configuration.
Why wrong: Incorrect. The bfd neighbor command is used for static BFD sessions, not for dynamic protocols like OSPF.
- D
Configure the router ospf command and then use the bfd all-interfaces command.
Why wrong: Incorrect. While bfd all-interfaces enables BFD on all OSPF interfaces, it still requires the interface-level bfd interval command to be present; this option alone is insufficient.
- E
Configure the bfd slow-timers command under the interface.
Why wrong: Incorrect. The bfd slow-timers command is used for multihop BFD sessions and is not required for single-hop OSPF BFD.
300-410 Bidirectional Forwarding Detection (BFD) Practice Question
This 300-410 practice question tests your understanding of bidirectional forwarding detection (bfd). This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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.
An engineer must enable BFD for an OSPF single-hop session between two directly connected routers. Which TWO configuration changes are required on each router? (Choose TWO.)
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
Configure the bfd interval command under the interface.
To enable BFD for OSPF, you must first enable BFD on the interface (bfd interval) and then enable BFD support under the OSPF routing process or interface (ip ospf bfd). The bfd neighbor command is for static BFD sessions, not OSPF. The router ospf command alone does not enable BFD. The bfd all-interfaces command enables BFD on all OSPF interfaces but still requires interface-level BFD configuration.
Key principle: OSPF neighbour adjacency depends on matching area, hello/dead timers, network type, and authentication — IP reachability alone is not enough.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Configure the bfd interval command under the interface.
Why this is correct
Correct. The bfd interval command enables BFD on the interface and sets the timers.
Related concept
OSPF neighbours must agree on key parameters.
- ✓
Configure the ip ospf bfd command under the interface.
- ✗
Configure the bfd neighbor command under global configuration.
Why it's wrong here
Incorrect. The bfd neighbor command is used for static BFD sessions, not for dynamic protocols like OSPF.
- ✗
Configure the router ospf command and then use the bfd all-interfaces command.
Why it's wrong here
Incorrect. While bfd all-interfaces enables BFD on all OSPF interfaces, it still requires the interface-level bfd interval command to be present; this option alone is insufficient.
- ✗
Configure the bfd slow-timers command under the interface.
Why it's wrong here
Incorrect. The bfd slow-timers command is used for multihop BFD sessions and is not required for single-hop OSPF BFD.
Common exam traps
Common exam trap: OSPF can fail even when IP connectivity looks correct
OSPF neighbour formation depends on matching areas, timers, network type, authentication and passive-interface behaviour. Do not choose an answer only because the devices can ping.
Trap categories for this question
Command / output trap
Incorrect. The bfd neighbor command is used for static BFD sessions, not for dynamic protocols like OSPF.
Detailed technical explanation
How to think about this question
OSPF questions usually test the details that control adjacency and route selection. Read the neighbour state, area, router ID and interface configuration before deciding what is wrong.
KKey Concepts to Remember
- OSPF neighbours must agree on key parameters.
- Router ID selection can affect neighbour relationships and LSDB output.
- OSPF cost influences the preferred path.
- A route can appear in OSPF information but not become the installed route.
TExam Day Tips
- Check area mismatch first when OSPF adjacency fails.
- Review passive interfaces when a network is advertised but no neighbour forms.
- Use show ip ospf neighbor and show ip route clues carefully.
Key takeaway
OSPF neighbour adjacency depends on matching area, hello/dead timers, network type, and authentication — IP reachability alone is not enough.
Real-world example
How this comes up in practice
A network engineer at a university connects two campus buildings via a fibre link. Both routers run OSPF, but no adjacency forms — even though both routers can ping each other. The engineer finds one router is in area 0 and the other in area 1. OSPF adjacency requires matching area numbers, hello/dead timers, and network type. IP reachability alone is not enough.
What to study next
Got this wrong? Here's your next step.
Review OSPF neighbour requirements — matching area type, hello and dead timers, network type, stub flags, and authentication. Study show ip ospf neighbor states (INIT, 2-WAY, FULL). Then practise related 300-410 OSPF questions on adjacency and route selection.
- →
Bidirectional Forwarding Detection (BFD) — study guide chapter
Learn the concepts, then practise the questions
- →
Bidirectional Forwarding Detection (BFD) 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
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.
FAQ
Questions learners often ask
What does this 300-410 question test?
Bidirectional Forwarding Detection (BFD) — This question tests Bidirectional Forwarding Detection (BFD) — OSPF neighbours must agree on key parameters..
What is the correct answer to this question?
The correct answer is: Configure the bfd interval command under the interface. — To enable BFD for OSPF, you must first enable BFD on the interface (bfd interval) and then enable BFD support under the OSPF routing process or interface (ip ospf bfd). The bfd neighbor command is for static BFD sessions, not OSPF. The router ospf command alone does not enable BFD. The bfd all-interfaces command enables BFD on all OSPF interfaces but still requires interface-level BFD configuration.
What should I do if I get this 300-410 question wrong?
Review OSPF neighbour requirements — matching area type, hello and dead timers, network type, stub flags, and authentication. Study show ip ospf neighbor states (INIT, 2-WAY, FULL). Then practise related 300-410 OSPF questions on adjacency and route selection.
What is the key concept behind this question?
OSPF neighbours must agree on key parameters.
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 18, 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.