NSE7 Troubleshooting and Diagnostics Practice Question
A FortiGate administrator sees the following kernel log: 'kernel: [pid 1234] received packet with unknown or unsupported protocol 0x0800 on interface port1, drop'. What does this log indicate?
⚠ Common exam trap
The trap here is that candidates see 'unknown or unsupported protocol 0x0800' and assume it refers to an exotic or malformed protocol, when in fact 0x0800 is standard IPv4 and the issue is a missing IP address or VDOM assignment on the interface.
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 interface is not configured with an IP address or is in the wrong VDOM.
The kernel log indicates that the interface port1 received an Ethernet frame with EtherType 0x0800 (IPv4) but the FortiGate dropped it because the interface is either not configured with an IP address or is bound to the wrong VDOM. Without an IP address or proper VDOM assignment, the kernel cannot process the packet at Layer 3, so it logs the packet as having an 'unknown or unsupported protocol' even though 0x0800 is standard IPv4.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The packet is an ARP request that failed.
Why it's wrong here
ARP uses protocol type 0x0806.
- ✗
The packet has an invalid MAC address.
Why it's wrong here
MAC address issues generate different logs.
- ✓
The interface is not configured with an IP address or is in the wrong VDOM.
Why this is correct
The kernel drops packets when the interface is not configured to handle that protocol.
- ✗
The packet has IP options set that are not supported.
Why it's wrong here
IP options would be handled at a higher layer.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.