NSE7 Troubleshooting and Diagnostics Practice Question
An administrator is troubleshooting why a FortiGate is dropping traffic from a specific source IP (10.1.1.100). The administrator wants to see real-time per-packet details including the reason for drops. Which CLI command should the administrator use?
⚠ Common exam trap
The trap here is assuming that setting the filter alone or enabling debug globally is sufficient, when in fact all three steps are required to capture and display the relevant flow information.
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
✓
diagnose debug flow filter addr 10.1.1.100 && diagnose debug flow trace start 100 && diagnose debug enable
To troubleshoot dropped traffic from a specific source IP, the administrator must set a filter, start the flow trace, and enable debug output. The combination of 'diagnose debug flow filter addr', 'diagnose debug flow trace start', and 'diagnose debug enable' provides real-time per-packet details including drop reasons, allowing effective diagnosis.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
diagnose debug enable
Why it's wrong here
This command enables debug output globally, but without a filter it will produce overwhelming output from all debug sources. It does not focus on the specific source IP or provide per-packet details with drop reasons. The administrator must first set a filter using 'diagnose debug flow filter' and then enable the flow debug specifically.
- ✗
diagnose debug flow filter addr 10.1.1.100
Why it's wrong here
This command only sets a filter for the debug flow output; it does not enable or display any debug messages. Without enabling 'diagnose debug enable', no output is generated. The administrator needs to both set the filter and enable debugging, but this command alone does not provide the required real-time per-packet details.
- ✓
diagnose debug flow filter addr 10.1.1.100 && diagnose debug flow trace start 100 && diagnose debug enable
Why this is correct
This sequence correctly sets a filter for the source IP, starts a flow trace for 100 packets, and enables debug output. The 'diagnose debug flow' commands provide detailed per-packet information including the reason for drops, which is exactly what the administrator needs to troubleshoot the issue.
- ✗
diagnose debug flow trace start 100
Why it's wrong here
This command starts a flow trace for 100 packets, but it requires that a filter be set beforehand to capture only traffic from 10.1.1.100. Without the filter, it will trace all traffic, making it difficult to isolate the issue. Additionally, the trace must be enabled with 'diagnose debug enable' to see output.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Fortinet exam blueprint
This NSE7 practice question is part of Courseiva's free Fortinet 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 NSE7 exam.