JN0-106 User Interfaces Practice Question
An engineer wants to view system log messages as they are generated in real-time. Which command should they use?
⚠ Common exam trap
The trap here is that candidates familiar with Cisco IOS may confuse 'show log' (which in Cisco shows a static log) with Junos 'show log messages', and incorrectly assume it provides real-time output, while 'monitor log messages' is the correct real-time equivalent.
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 log messages
The 'monitor log messages' command in Junos OS provides a real-time view of system log messages as they are generated, similar to the 'tail -f' command on Unix systems. It streams new log entries to the terminal without requiring manual refresh, making it ideal for live monitoring of events.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
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start log messages
Why it's wrong here
The Junos CLI does not include a 'start log messages' command. The keyword 'start' is not used for operational real-time monitoring; Junos uses 'monitor' for streaming commands such as 'monitor log' or 'monitor traffic'. Attempting to enter 'start log messages' will result in an error, and this is not a valid way to view system log messages as they are generated.
- ✓
monitor log messages
Why this is correct
The 'monitor log messages' command is the correct operational command for real-time log viewing. It streams new log entries to the terminal as they are written by the syslog process, similar to the Unix 'tail -f' command. The engineer can stop the streaming output by pressing Ctrl+C, and can optionally use the 'match' filter to display only relevant messages.
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request system log
Why it's wrong here
The 'request system log' command is not a valid Junos operational command. The 'request system' hierarchy is used for administrative actions such as 'request system reboot', 'request system halt', or 'request system configuration rescue save' — not for streaming logs. For real-time log monitoring, Junos relies on the 'monitor' family of commands, not the 'request' family.
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show log messages
Why it's wrong here
The 'show log messages' command is commonly confused with real-time monitoring, but it only displays the stored contents of the log file at the moment the command is executed. It does not follow new entries as they arrive; to see updated messages, the command must be re-run. While 'show log messages | follow' can provide streaming, the plain command is not real-time, and the question specifically asks for viewing messages as they are generated.
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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.