Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
A technician is troubleshooting a user's computer that cannot access any network resources. The technician runs ipconfig and sees an IP address of 169.254.18.33 with a subnet mask of 255.255.0.0. The computer is connected to a switch port configured for VLAN 10. The DHCP server is located in a different subnet (VLAN 200) and is reachable via a router. The technician confirms that the switch port is in the correct VLAN and that the cabling is good. Which of the following is the MOST likely cause of the issue?
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
The DHCP server is not authorized in Active Directory
DHCP server authorization is relevant for Windows environments but would not typically cause the client to receive an APIPA address; it would either fail or get a valid lease.
B
Best answer
The router does not have a DHCP relay (ip helper-address) configured
Without a DHCP relay, DHCP broadcast requests from the client in VLAN 10 cannot reach the DHCP server in VLAN 200, leading to APIPA assignment.
C
Distractor review
The computer's NIC is faulty
A faulty NIC would likely show no link or erratic behavior, not a stable APIPA address. The client can obtain a link-local address, indicating the NIC is functional.
D
Distractor review
The switch port is in the wrong VLAN
The technician already confirmed the port is in the correct VLAN. An incorrect VLAN would likely result in no network access at all, but the APIPA address suggests DHCP failure, not a VLAN mismatch.
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.
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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 router does not have a DHCP relay (ip helper-address) configured — The IP address 169.254.x.x is an Automatic Private IP Addressing (APIPA) address, assigned by the operating system when it fails to receive a DHCP lease. The computer is in one VLAN while the DHCP server is in another, indicating that a DHCP relay (IP helper) is required on the router to forward DHCP broadcasts to the DHCP server. Without a properly configured DHCP relay, the DHCP client's broadcast requests will not reach the DHCP server in a different subnet. Options A and C are possible but less likely given the correct VLAN assignment and known reachable server. Option D, incorrect subnet mask, would not cause an APIPA address; instead the client would likely have a valid IP from a wrong subnet if DHCP succeeded. Therefore, the missing DHCP relay is the most probable cause.
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
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