Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
A network technician is troubleshooting inter-VLAN routing. Hosts in VLAN 10 can communicate with hosts in VLAN 20, but cannot communicate with hosts in VLAN 30. All VLANs are configured on the same Layer 3 switch with SVIs. Which of the following should the technician verify FIRST?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Distractor review
VLAN 30 is not allowed on the trunk port to the switch.
Trunk ports are used for inter-switch links; since all VLANs are on the same switch, this is not relevant.
B
Best answer
The SVI for VLAN 30 is missing an IP address.
An SVI without an IP address cannot route traffic, which would prevent inter-VLAN communication for that VLAN.
C
Distractor review
The default gateway on hosts in VLAN 10 is incorrect.
If the default gateway were incorrect, hosts in VLAN 10 would likely fail to reach both VLAN 20 and VLAN 30.
D
Distractor review
The routing table does not have a route to VLAN 30.
A missing route could be caused by an unconfigured SVI; verifying the SVI first is more direct.
Common exam trap
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.
Technical deep dive
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.
Related practice questions
Related N10-009 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Network+ network fundamentals practice questions
Practise N10-009 questions linked to Network+ network fundamentals.
Network+ implementation practice questions
Practise N10-009 questions linked to Network+ implementation.
Network+ operations practice questions
Practise N10-009 questions linked to Network+ operations.
Network+ security practice questions
Practise N10-009 questions linked to Network+ security.
Network+ troubleshooting practice questions
Practise N10-009 questions linked to Network+ troubleshooting.
More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A network engineer needs to connect two switches located 400 meters apart. The cable run includes high electromagnetic interference from nearby machinery. The engineer decides to use fiber optic cabling. Which transceiver type and fiber combination should be used to ensure the link reaches 400 meters while remaining cost-effective?
Question 2
A network engineer is designing a new switched network and needs to ensure that broadcast traffic from one department does not reach another department's workstations. The engineer plans to use VLANs. Which of the following must be configured on the switches to isolate broadcast domains as intended?
Question 3
A security engineer is configuring a site-to-site VPN between two branch offices. The requirement is to encrypt all traffic between the two networks using IPsec. Which IPsec mode should be used to encrypt the entire IP packet including the original header?
Question 4
A network administrator is connecting two switches to increase bandwidth and provide redundancy. Which technology should be used to combine multiple physical links into a single logical link?
Question 5
A network administrator is experiencing issues where unauthorized devices are offering IP addresses to clients, causing connectivity problems. Which security feature should be enabled on switches to prevent this?
Question 6
A network administrator is troubleshooting a connectivity issue and suspects the problem is related to the physical cabling. At which layer of the OSI model should the administrator begin their investigation?
FAQ
Questions learners often ask
What does this N10-009 question test?
Access ports place end devices into a single VLAN.
What is the correct answer to this question?
The correct answer is: The SVI for VLAN 30 is missing an IP address. — Since hosts in VLAN 10 can reach VLAN 20 but not VLAN 30, the issue is specific to VLAN 30. The most common cause on a Layer 3 switch is that the SVI for VLAN 30 is not configured with an IP address, making it unable to route traffic. Option B addresses this directly. Option A is incorrect because trunk ports are only relevant when traversing multiple switches. Option C is unlikely to affect only VLAN 30. Option D could be a symptom, but missing an IP on the SVI would also cause a missing route, so checking the SVI first is more efficient.
What should I do if I get this N10-009 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
Discussion
Loading comments…
Sign in to join the discussion.