JN0-106 Junos OS Fundamentals Practice Question
Exhibit
Refer to the exhibit.
user@router> show configuration interfaces ge-0/0/0
unit 0 {
family inet {
address 10.0.0.1/30;
}
}
user@router> show interfaces terse ge-0/0/0
Interface Admin Link Proto Local Remote
ge-0/0/0 up up inet 10.0.0.1/30
user@router> ping 10.0.0.2 count 1
PING 10.0.0.2 (10.0.0.2): 56 data bytes
^C
--- 10.0.0.2 ping statistics ---
1 packets transmitted, 0 packets received, 100% packet lossBased on the exhibit, what is the most likely reason for the ping failure?
⚠ Common exam trap
Test-takers frequently assume a ping failure is due to an interface being down or a firewall filter, but the exhibit clearly shows the interface is up and enabled, so the issue must be at the network layer with neighbor unreachability.
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 neighbor device is not configured or is unreachable.
The ping failure is most likely due to the neighbor device not being configured or unreachable because the output shows the interface is up (Physical link is Up) and the unit is enabled (Unit 0 is enabled), but there is no neighbor discovery or ARP entry. Without a valid next-hop or neighbor reachability, ICMP echo requests cannot be forwarded, resulting in ping failure.
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 firewall filter is blocking ICMP traffic.
Why it's wrong here
The exhibit shows no firewall filter configuration or any applied filter that could drop ICMP. In Junos, firewall filters are explicitly configured and applied to interfaces; without such a filter, the packet would not be dropped by a local filter. A ping failure more likely points to routing or neighbor reachability issues, not an invisible filter.
- ✗
The interface is disabled at the unit level.
Why it's wrong here
A unit-level disable would be indicated by a 'disable' statement under the logical unit configuration, and the operational status would typically show the unit as down or disabled. The exhibit does not display any such configuration, and the unit appears operationally active. In Junos, disabling a logical unit is an administrative action that would be explicitly configured, not assumed.
- ✓
The neighbor device is not configured or is unreachable.
Why this is correct
The interface status is up/up, meaning the physical link has carrier and the logical unit is active, but this does not guarantee the remote host at 10.0.0.2 is reachable. The ping fails because either the neighbor device is not configured with that IP address, is powered off, or there is no route in the routing table to reach it. A successful ping requires an active ARP entry or a valid route, not just a local interface that is administratively up.
- ✗
The interface is administratively down.
Why it's wrong here
The exhibit explicitly shows the administrative status as 'up', which indicates the interface is not administratively down. In Junos, an administratively down interface would have an admin status of 'down' and would require a 'disable' statement in the configuration. Since this is not the case, the problem lies elsewhere, such as the remote destination being unreachable.
Go deeper
Related to this question
About these practice questions
One of 326 original JN0-106 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This JN0-106 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 JN0-106 exam.