JNCIS-ENT OSPF Practice Question
What is the OSPF router ID format used by Junos OS when initializing the OSPF routing process if no explicit router ID is configured?
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
✓
A 32-bit IPv4 address format (dotted quad)
OSPF router IDs are formatted as a 32-bit dotted-quad number, identical in structure to an IPv4 address.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
A 48-bit MAC address
Why it's wrong here
Incorrect. MAC addresses are used at Layer 2, not as OSPF router IDs.
- ✗
An integer value between 1 and 65535
Why it's wrong here
Incorrect. AS numbers use 16-bit or 32-bit integers, whereas OSPF router IDs are dotted quads.
- ✗
A 128-bit IPv6 address
Why it's wrong here
Incorrect. OSPFv2 uses 32-bit router IDs.
- ✓
A 32-bit IPv4 address format (dotted quad)
Why this is correct
Correct. OSPF router IDs are 32-bit values represented as IPv4 addresses.
Visual reference
About these practice questions
This JNCIS-ENT question is part of Courseiva's 506-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 and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed August 2026 · checked against the official Juniper Networks exam blueprint
This JNCIS-ENT practice question is part of Courseiva's free Juniper Networks 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 JNCIS-ENT exam.