JNCIS-ENT IS IS Practice Question
How does a router determine its System ID?
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
✓
It is manually configured.
The System ID is manually configured in the 'set protocols isis system-id' hierarchy.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
It is learned via ARP.
Why it's wrong here
ARP is for L2/L3 mapping.
- ✗
It is automatically derived from the MAC address.
Why it's wrong here
While it can look like one, it must be manually configured in Junos.
- ✓
It is manually configured.
Why this is correct
The administrator defines this value.
- ✗
It is assigned by the DIS.
Why it's wrong here
System IDs are static.
About these practice questions
Courseiva writes every JNCIS-ENT question from scratch — 506 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or 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.