A network technician is troubleshooting inter-VLAN routing. Clients on VLAN 10 (192.168.10.0/24) cannot communicate with servers on VLAN 20 (192.168.20.0/24). The router has subinterfaces for both VLANs and is connected to a layer 2 switch. The switch port connecting to the router is configured as an access port in VLAN 10. An ACL on the router is configured to permit all traffic between the VLANs. 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.
Distractor review
The ACL on the router is misconfigured
The ACL is set to permit all traffic, so it is not blocking communication. Even if the ACL were misconfigured, the router would still need to receive the packets first.
Best answer
The switch port is not configured as a trunk
For router-on-a-stick to work, the switch port must be a trunk port to carry traffic for both VLANs. With an access port, only one VLAN's traffic passes, breaking inter-VLAN routing.
Distractor review
The default gateway on the servers is set incorrectly
Even if the servers had an incorrect gateway, the clients in VLAN 10 are able to send packets; the issue is that the router never receives packets from VLAN 20.
Distractor review
VLAN 20 is not defined on the switch
If VLAN 20 did not exist, devices on VLAN 20 would not have connectivity at all. The scenario assumes servers exist on VLAN 20, so the VLAN must be defined.
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 user reports intermittent network connectivity on a desktop computer. The technician observes that the Ethernet link light on the NIC turns off for a few seconds and then turns back on. The cable passes a wiremap test, the switch port is verified good with another device, and the NIC driver is updated. The issue occurs more frequently when the computer's case fan runs at high speed. Which of the following is the MOST likely cause?
Question 2
A workstation is unable to connect to the internet. The technician runs the 'ipconfig' command and sees the IPv4 address is 169.254.15.200 with a subnet mask of 255.255.0.0. The workstation can ping other devices on the local subnet but cannot ping the default gateway or any external addresses. Which TWO actions should the technician take to resolve this issue? (Select two.)
Question 3
A workstation is connected to a managed switch. It obtains a valid IP address (192.168.10.50) from the DHCP server, but it cannot ping the default gateway (192.168.10.1). The link light on both the workstation NIC and the switch port are solid green. Other workstations on the same switch CAN ping the default gateway successfully. The technician accesses the switch management interface and finds that the workstation's port is configured as an access port on VLAN 10. The default gateway is located on VLAN 20. An inter-VLAN router is configured but not explicitly allowing VLAN 10 access to VLAN 20. Which of the following is the MOST likely cause of the problem?
Question 4
A company develops a web application that relies on a custom library available only for a specific Linux distribution. They want to deploy the application in the cloud with minimal administrative overhead, but they need full control over the software stack, including the ability to install the custom library and configure the web server. Which cloud service model BEST meets these requirements?
Question 5
A company has a legacy virtual machine running on a deprecated hypervisor (Hyper-V). They want to migrate this VM to a new hypervisor (VMware vSphere) hosted in a private cloud while preserving the VM's configuration, installed applications, and data. The migration must be performed with minimal downtime. Which of the following methods is MOST appropriate?
Question 6
A company hosts a critical database on a virtual machine in a public cloud. The database requires persistent storage that must be retained even if the VM is terminated. The storage must also be accessible from multiple VMs simultaneously for a future high-availability configuration. Which type of cloud storage BEST meets these requirements?
FAQ
Questions learners often ask
What does this 220-1101 question test?
Access ports place end devices into a single VLAN.
What is the correct answer to this question?
The correct answer is: The switch port is not configured as a trunk — The switch port connecting to the router must be configured as a trunk port to carry traffic for multiple VLANs. Since the port is set as an access port in VLAN 10, it only passes traffic for VLAN 10. Packets from VLAN 20 are dropped at the switch port, preventing the router from reaching servers in VLAN 20. This is a classic router-on-a-stick configuration requirement.
What should I do if I get this 220-1101 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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