The answer is an incorrect native VLAN configuration on the vNIC within the UCS service profile. PXE boot relies on the client sending an untagged DHCP discover broadcast, which the fabric interconnect must place onto the correct VLAN; if the vNIC’s native VLAN does not match the PXE/DHCP subnet, these frames are either dropped or forwarded on the wrong VLAN, so the DHCP server never sees the request and the blade falls through to the local disk. On the Cisco DCCOR 350-601 exam, this scenario tests your understanding of UCS networking fundamentals, specifically how the native VLAN tag (or lack thereof) controls untagged traffic on a vNIC—a common trap is assuming the default VLAN on the fabric interconnect is automatically applied to the vNIC, when in fact it must be explicitly set in the service profile. Remember the memory tip: “Untagged traffic needs a matching native VLAN to reach its subnet; otherwise, PXE requests vanish into the wrong broadcast domain.”
350-601 Compute Practice Question
This 350-601 practice question tests your understanding of compute. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A startup company is deploying a new web application on UCS B-Series blades. They want to use PXE boot for rapid provisioning. The network team has configured a DHCP server and a PXE server on the same VLAN as the UCS service profiles. The system administrator creates a service profile for a blade and sets the boot policy to 'PXE' as the first boot device, and local disk as second. However, when the blade powers on, it boots from the local disk instead of PXE. The PXE server logs show no request from the blade's MAC address. The DHCP server logs show no activity. The fabric interconnect is configured with a default VLAN. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "first"
Why it matters: Order matters here. You are being tested on which action comes before the others — not which action is generally useful.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The vNIC on the service profile is not configured with the correct native VLAN
Option A is correct because PXE boot requires the vNIC to have an untagged native VLAN that matches the PXE/DHCP subnet. If the native VLAN on the vNIC is different, DHCP requests are not forwarded. Option B wrong because PXE boot order is usually correct. Option C wrong because it would cause different symptoms. Option D wrong because service profile association is fine.
Key principle: A trunk being up does not mean the VLAN is allowed across it. Always verify the allowed VLAN list and whether the VLAN exists on both switches.
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 vNIC on the service profile is not configured with the correct native VLAN
The clue words "first", "most likely" in the question point toward this answer.
Related concept
Access ports place end devices into a single VLAN.
✗
The boot policy order lists local disk before PXE
Why it's wrong here
The stem says PXE is first
✗
The service profile is not properly associated with the blade
Why it's wrong here
Association would not affect PXE; server boots anyway
✗
The fabric interconnect uplinks are not in trunk mode
Why it's wrong here
Uplinks usually trunk; would affect all traffic, not just PXE
Common exam traps
Common exam trap: an active trunk can still block the VLAN you need
A trunk being up does not prove every VLAN is crossing it. Check allowed VLAN lists, native VLAN mismatch, VLAN existence and access-port assignment.
Detailed technical explanation
How to think about this question
VLAN questions usually combine access-port and trunking clues. The key is to identify whether the issue is local to one switchport, caused by the trunk, or caused by the VLAN not existing where it needs to exist.
KKey Concepts to Remember
Access ports place end devices into a single VLAN.
Trunk ports carry multiple VLANs between switches.
Allowed VLAN lists decide which VLANs can cross a trunk.
Native VLAN mismatch can create confusing symptoms.
TExam Day Tips
→Use show vlan brief to verify access VLANs.
→Use show interfaces trunk to verify trunk state and allowed VLANs.
→Do not treat every same-VLAN issue as a routing problem.
Key takeaway
A trunk being up does not mean the VLAN is allowed across it. Always verify the allowed VLAN list and whether the VLAN exists on both switches.
Real-world example
How this comes up in practice
A help-desk technician troubleshoots why a newly connected PC cannot reach shared printers on the same floor. The cable is good, the switch port is active, but the PC is in VLAN 20 and the printers are in VLAN 10. The uplink trunk only allows VLAN 10. A trunk being up does not mean every VLAN crosses it.
What to study next
Got this wrong? Here's your next step.
Review VLAN allowed lists, native VLAN mismatch detection, and how to verify VLAN membership with show vlan brief and show interfaces trunk. Then practise related 350-601 questions on switching, trunking, and access-port configuration.
Compute — This question tests Compute — Access ports place end devices into a single VLAN..
What is the correct answer to this question?
The correct answer is: The vNIC on the service profile is not configured with the correct native VLAN — Option A is correct because PXE boot requires the vNIC to have an untagged native VLAN that matches the PXE/DHCP subnet. If the native VLAN on the vNIC is different, DHCP requests are not forwarded. Option B wrong because PXE boot order is usually correct. Option C wrong because it would cause different symptoms. Option D wrong because service profile association is fine.
What should I do if I get this 350-601 question wrong?
Review VLAN allowed lists, native VLAN mismatch detection, and how to verify VLAN membership with show vlan brief and show interfaces trunk. Then practise related 350-601 questions on switching, trunking, and access-port configuration.
Are there clue words in this question I should notice?
Yes — watch for: "first", "most likely". Order matters here. You are being tested on which action comes before the others — not which action is generally useful.
What is the key concept behind this question?
Access ports place end devices into a single VLAN.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This 350-601 practice question is part of Courseiva's free Cisco 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 350-601 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.