JN0-106 Operational Monitoring and Maintenance Practice Question
To monitor interface traffic in real-time, which operational command is most appropriate?
⚠ Common exam trap
The trap here is that candidates familiar with Cisco IOS may mistakenly expect a 'show interface traffic' command (similar to 'show interfaces' with counters) and overlook the Junos-specific 'monitor interface' command for real-time updates.
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
✓
monitor interface
The 'monitor interface' command in Junos provides real-time, continuous display of interface statistics and traffic counters, updating every second by default. This is the correct operational command for live traffic monitoring, as it refreshes the output dynamically without requiring manual re-entry.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
show interface traffic
Why it's wrong here
"show interface traffic" is not a valid Junos CLI command because the grammar requires the plural "interfaces" for operational display, and "traffic" is not a recognized modifier. Even the valid "show interfaces statistics" or "show interfaces extensive" commands produce only a static, one-time snapshot of counters, not a continuously updating real-time view, so this option cannot fulfill the monitoring requirement.
- ✗
request system reboot
Why it's wrong here
"request system reboot" is a Junos operational command that schedules or immediately performs a system restart, typically used to apply new software or recover from a system issue. It has no interface-traffic monitoring capability and is inherently disruptive: rebooting the device stops all interface forwarding and monitoring activity, making it the opposite of a real-time monitoring tool in a production network.
- ✗
show log
Why it's wrong here
"show log" displays the contents of Junos system log files, such as events, errors, and administrative actions recorded by various processes. While firewall filters can be configured to log traffic, that is a separate, non-default mechanism and the output is written to disk rather than streamed in real time; the command itself does not sample interface data-plane counters, so it cannot provide live traffic rates.
- ✓
monitor interface
Why this is correct
"monitor interface" is the correct Junos operational command for real-time interface monitoring. It repeatedly samples the specified interface's counters — showing input/output packets per second, bytes per second, and error counts — and refreshes the output at a configurable interval using the "interval" option, making it ideal for watching live traffic patterns, congestion, or interface flaps.
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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.