Question 1hardmultiple choice
Full question →hardmultiple choiceObjective-mapped
A network technician is configuring a router-on-a-stick for inter-VLAN routing. The router has one physical interface (G0/0) connected to a managed switch. The technician creates subinterfaces G0/0.10 for VLAN 10 (192.168.10.1/24) and G0/0.20 for VLAN 20 (192.168.20.1/24). The switch port connected to the router is configured as a trunk allowing VLANs 10 and 20. On a workstation in VLAN 10, the technician can ping the gateway 192.168.10.1 but cannot ping the gateway 192.168.20.1. Which of the following is the MOST likely cause?
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 switch trunk port is set to the wrong native VLAN
A mismatch in native VLAN could cause connectivity issues, but both VLANs would likely be affected, not just VLAN 20. Also, the workstation can ping its own gateway, indicating the trunk passes VLAN 10 traffic correctly.
B
Best answer
The subinterface G0/0.20 is missing the encapsulation dot1Q 20 command
Without the encapsulation dot1Q command on G0/0.20, the subinterface will not associate incoming frames with VLAN 20. The router may still have the IP address configured, but it will not process tagged frames from VLAN 20, so workstations in VLAN 10 cannot reach the VLAN 20 gateway.
C
Distractor review
The workstation in VLAN 10 has an incorrect subnet mask
An incorrect subnet mask might prevent the workstation from reaching other networks, but it can still ping its own gateway (192.168.10.1). The issue is specifically with reaching the VLAN 20 gateway, which is a routing problem, not a host configuration issue.
D
Distractor review
The router interface G0/0 is in a VLAN that is not allowed on the trunk
The trunk allows both VLANs 10 and 20, and VLAN 10 works. If VLAN 20 were not allowed on the trunk, no traffic from VLAN 20 would reach the router, which could cause the symptom, but the configuration shows the trunk allows both. The absence of encapsulation is a more precise and common cause.
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 subinterface G0/0.20 is missing the encapsulation dot1Q 20 command — In a router-on-a-stick configuration, each subinterface must be configured with the encapsulation dot1Q command to tag traffic for the appropriate VLAN. If this command is missing, the subinterface will not accept or transmit tagged frames, effectively breaking inter-VLAN routing for that VLAN. Since VLAN 10 works, its subinterface is likely configured correctly. VLAN 20's subinterface probably lacks the encapsulation dot1Q 20 command. The IP addresses are reachable from within their respective VLANs if the subinterface is enabled, but without proper encapsulation, the router cannot process frames from that VLAN.
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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